[Federal Register: November 14, 2000 (Volume 65, Number 220)]
[Rules and Regulations]
[Page 68411-68460]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14no00-17]
[[pp. 68411-68460]] Ergonomics Program
[[Continued from page 68410]]
[[Page 68411]]
As mentioned above, OSHA received many comments (see, e.g., Exs.
30-2116; 30-2809; 30-2825; 30-2847; 30-3258; 30-3035; 30-3001; 30-3033;
30-3034; 30-3686; 30-4159; 30-4534; 30-4536; 30-4800; 30-4776; 30-4546;
30-4547; 30-4548; 30-4549; 30-4562; 30-4627; 30-3332; 30-3259; 30-4801;
30-3898; 30-4270; 30-4498; 31-242; 32-210-2; 500-71-86) stating that
program evaluations should take place at least annually. These
commenters generally argued, in the words of Greg Wyatt, an engineer
who suffers from a repetitive stress injury and who offered comments as
an individual, that ``the ergonomics program should be evaluated
regularly (at least once a year) because it is easier and more cost
effective to fix deficiencies early during the implementation phase''
(Ex. 30-3035). In a comment that pertains to all workplaces, the United
Mineworkers of America agreed, ``Routine audits, no less frequently
than once each year, should be performed of the entire workplace and
problem areas reported to the appropriate company representative for
immediate action'' (Ex. 500-71-86).
The need for evaluations at a minimum frequency of less than 3
years was addressed by several commenters (see, e.g., Exs. 30-2116; 30-
2809; 30-2825; 30-2847; 30-3258; 30-3035; 30-3001; 30-3033; 30-3034;
30-3686; 30-4159; 30-4534; 30-4536; 30-4800; 30-4776; 30-4546; 30-4547;
30-4548; 30-4549; 30-4562; 30-4627; 30-3332; 30-3259; 30-4801; 30-3898;
30-4270; 30-4498; 32-210-2; 32-111-4; 32-229; 30-4247), who pointed out
that workplace changes that adversely affect the functioning of a
particular element of the program or of the program as a whole can
occur in the interval between periodic evaluations (or ``regularly
scheduled'' evaluations). For example, the United Steelworkers of
America (UOWA) agreed that employers should evaluate their ergonomics
programs at least every 3 years but asked OSHA to include in the final
rule requirements that would trigger evaluations at more frequent
intervals as well. ``OSHA should provide additional specific
requirements for the employer to respond to concerns raised by workers
between evaluations. For example, employers should review health and
safety committee minutes to determine if ergonomic concerns were
identified, [and] then they should verify that those concerns have been
promptly addressed or address them at that time'' (Ex. 32-111-4).
From a somewhat different perspective, Organization Resources
Counselors, Inc. (ORC) (Ex. 30-3813) and Edison Electric Institute
(EEI) (Ex. 500-33) asked that the standard's language be changed to
reflect their belief that a requirement to evaluate an ergonomics
program both periodically and every three years was excessive. Both
commenters agreed that the employer was in the best position to
determine how often the ergonomics program at a particular worksite
needs to be evaluated to ensure its effectiveness. However, in ORC's
words, ``it is not reasonable that the standard should require both
periodic evaluation as well as an evaluation every three years.'' These
commenters urged OSHA to require employers to evaluate their ergonomics
programs periodically, ``and/or'' at least every 3 years.
Another rulemaking participant, the National Soft Drink Association
(NSDA) (Ex. 30-368) questioned whether performance of a program
evaluation every 3 years also would satisfy the proposed requirement
for periodic evaluations. Because, NSDA believes that the two
provisions are duplicative, it recommended that the term ``periodic''
be eliminated. The Dow Chemical Company (Ex. 30-3765) also opposed the
``at least every 3 years'' language, on the grounds that industry
should be able to decide if and when periodic evaluations should be
carried out but agreed that periodic reviews are necessary: * * *
review on a periodic basis is necessary, especially * * * for dynamic
workplaces with continuous turnover, process changes, etc.'' The
National Telecommunications Safety Panel (Ex. 30-3745) agreed, saying
the proposed rule's prescribed frequency presented particular problems
for them because of their members' geographic sweep and rapidly
changing workplaces and that [determining] ``program evaluation
frequency * * * [should be] the sole responsibility of the employer.''
A few commenters (see, e.g., Exs. 30-4713 and 30-4046) stated that
the proposal's requirements for program evaluation were excessive: ``*
* * a complete evaluation, as required by the rule, cannot be
realistically performed `periodically,' as that term is defined.''
A number of commenters who have themselves experienced MSDs (see,
e.g., Exs. 30-2116; 30-2809; 30-2825; 30-2847; 30-3258; 30-3035; 30-
3001; 30-3033; 30-3034; 30-3686; 30-4159; 30-4534; 30-4536; 30-4800;
30-4776; 30-4546; 30-4547; 30-4548; 30-4549; 30-4562; 30-4627; 30-3332;
30-3259; 30-4801; 30-3898; 30-4270; 30-4498) also urged OSHA to require
in the final rule that ``every time an employee reports persistent MSD
symptoms or an MSD injury, Job Hazard Analysis and Control must be
performed, and the ergonomics program must be re-evaluated.'' In the
view of these commenters, every report of an MSD injury or persistent
MSD symptom points to a deficiency in the ergonomics program that must
be evaluated and corrected. OSHA agrees with these commenters that
significant changes in workplace conditions, such as the introduction
of a new process; changes in management or supervisory personnel,
procedures, or policies; or changes in the form or intensity of
employee involvement, can affect the functioning of the program
substantially and thus may necessitate an evaluation of particular
program elements or of the program as a whole.
However, the Agency has chosen not to shorten the minimum interval
between program evaluations to once a year from every three years
because such a requirement would prove to be too burdensome if imposed
on all of industry. Such a frequency would deprive employers of the
flexibility which was OSHA's goal in drafting the program evaluation
requirements, given the diversity of workplaces covered by this rule.
OSHA also is not persuaded that it would be appropriate to require
employers to evaluate their programs every time an MSD incident occurs
or an ergonomic concern is expressed, as some commenters urged the
Agency to do. Such a requirement would precipitate constant evaluations
for employers with large workforces, where the incidence of MSD
injuries is often high. OSHA does not expect that the program mandated
by the standard will eliminate MDSs in the workplaces covered by the
standard; indeed, as the discussion in Section VI of this preamble
makes clear, OSHA is projecting that, on average, the standard will
prevent about 50% of MSDs in such workplaces. Further, the Agency
believes that employee concerns about ergonomics will be addressed
regularly as a result of the standard's requirements for prompt
responses to employee concerns and regular employer/employee
communications about workers' concerns.
After a review of the evidence in the record on the frequency of
program evaluations, the final rule requires them when there is reason
to believe that the program is not functioning properly, when changes
have occurred that may have increased employee exposure to MSD hazards,
and at least once every three years. The final rule's requirements are
essentially similar to those proposed, although they are somewhat more
specific. OSHA's reasons for retaining provisions for program
evaluation that require such
[[Page 68412]]
evaluations at least once every 3 years and at other times if workplace
conditions warrant them, are: (1) the diversity of conditions in the
workplaces covered by the rule demands the combination of specificity
and flexibility provided by the provisions in paragraphs (u)(1) and (2)
all programs need to be evaluated at least once every 3 years to ensure
that they are functioning optimally and meeting the needs of the
organization over time.
Paragraph (u)(2)--Steps Involved in Program Evaluation
In the proposed section titled ``What must I do to evaluate my
ergonomics program?'', the proposed rule stated that program evaluation
goes beyond a mere inspection or audit of problem jobs. The final rule,
at paragraphs (u)(2)(i), (ii), (iii) and (iv ), contains similar
requirements. For example, the proposed rule would have required
employers to consult with employees in problem jobs to assess their
views about program effectiveness and identify program deficiencies,
paragraph (u)(2)(i) of the final rule requires employers to consult
with employees, ``or a representative sample of them,'' about program
effectiveness and any problems with the program. Paragraph (u)(2)(iii)
requires employers to evaluate the elements of a program to ensure it
is functioning effectively; this language is essentially unchanged
since the proposal. The proposal would have required employers to carry
out evaluations to ensure that the program was ``eliminating or
materially reducing'' MSD hazards, while the final rule at paragraph
(u)(2)(iii) requires the employer to assess whether MSD hazards are
being identified and ``addressed.'' The final rule adds, at paragraph
(u)(2)(iv), a requirement that employers use the evaluation as an
opportunity to assess whether the program as a whole is achieving
positive results. OSHA includes examples of measures of effectiveness,
such as reductions in the number or severity of MSDs, increases in the
number of jobs in which ergonomic hazards have been controlled,
reductions in the number of jobs posing MSD hazards to employees, or
any other measure that demonstrates program effectiveness.
An adequate evaluation asks questions of employers at all levels of
the organization to determine whether the required ergonomics program
elements have been adequately implemented and whether they are
integrated into a system that effectively addresses MSDs and MSD
hazards. Examples of questions an evaluation is designed to explore
are:
--Has management effectively demonstrated its leadership?
--Are employees actively participating in the ergonomics program?
--Is there an effective system for the identification of MSDs and MSD
hazards?
--Are identified hazards being controlled?
--Is the training program providing employees with the information they
need to actively participate in the ergonomics program?
--Are employees using the reporting system?
--Are employees reluctant to report MSDs or MSD hazards because they
receive mixed signals from their supervisors or managers about the
importance of such reporting?
--Is prompt and effective MSD management available for employees with
MSDs?
OSHA finds that these questions, which were included in the
proposal, continue to be appropriate points for program evaluations to
address. The comments OSHA received on the proposed requirements for
conducting evaluations addressed the following topics: the vagueness of
the proposed terms used; the inclusion of core elements in the program
required by the standard and in the standard's requirements for
evaluation; the need for OSHA to specify measures of effectiveness for
employers to rely on; the statement in the basic obligation section of
the proposed rule that programs should be evaluated to ensure that they
are in compliance with the standard itself; who should carry out
program evaluations; the records to be reviewed in a program
evaluation; and the extent of the recordkeeping required by this
provision of the standard. The comments OSHA received on each of these
topics are discussed below.
Vagueness of the rule's terminology: The Center for Office
Technology (COT) complained that some of the terms used in the context
of the proposed evaluation section were vague and ``subjective'' (Ex.
25-710). Specifically, COT pointed to the proposed requirement that
evaluations be conducted ``as often as necessary'' (defined in the
proposal as ``periodically'') as an example of the vagueness of the
proposal's language. COT stated, ``* * * training and program
evaluation must be conducted ``as often as necessary'' and the program
must be ``appropriate'' to workplace conditions. How will compliance
with these vague, undefined and subjective requirements be assessed?''
Inclusion of core elements in the program: The Forum for a
Responsible Ergonomics Standard (Exs. 32-351-1 and 30-3845) and others
(Exs. 30-574; 30-2773; 500-33; 30-4040) were critical of the proposed
Ergonomics Program standard's requirement that employers include in
their programs, and evaluate, six mandatory core elements. By mandating
that ergonomics programs have a certain form, i.e., have specific
elements, instead of requiring only that the program be effective, OSHA
was, according to the Forum, ``elevating form over function, divorcing
its program from [what should be] the goal of achieving reduced MSD
injuries and focusing instead on ensuring that programs fit a
bureaucratic mold that is administratively simple.'' In other words,
the Forum believes that the effectiveness of an ergonomics program
should be the sole measure of its success in any evaluation. The Forum
stated that the proposed approach to program evaluation could lead to
``the perverse possibility'' of an employer with a program that
successfully reduces MSDs being cited for a violation of the standard
merely because the program failed to include a required program
element.
Another commenter (Ex. 31-353) questioned how effective a program
evaluation could be unless the rule required the effectiveness of each
of the individual Ergonomic Program elements to be evaluated. ``Without
determining the effectiveness of all the aspects of the program, an
employer is wasting time and money, and effort.'' Similarly, the
Department of Defense (Tr. 9085-9086) stated, ``If the evaluation is
focused on the presence and function or process elements of the program
then the standard should clarify the essential evaluation points for
each program element.''
Compliance as a measure of effectiveness: The Dow Chemical Company
(Exs. 30-3765 and 32-77-2) asked, ``Is the point of program evaluation
to evaluate compliance with the standard or the program's
`effectiveness'? Or both?'' Dow's comment referred to a statement in
the basic obligation section of the proposed rule to the effect that
the program was to be evaluated to ensure its compliance with the
standard. According to Dow, ``If OSHA maintains the requirement to
evaluate `effectiveness' of a program, then it should indicate the
method an employer can use for measuring `effectiveness.' '' A program
may have all of the required elements and thus be in compliance with
the rule, but not address all potential MSDs'' (Ex. 30-3765). The
Association of Energy
[[Page 68413]]
Servicing Contractors (Tr. 15624) and others (Ex. 30-3839) agreed with
Dow about the need for measurable criteria with which to gauge
compliance with the standard.
Also commenting on this point was the Honorable Senator Christopher
S. Bond, Chairman of the United State Senate Committee on Small
Business, who submitted a study (Ex. 30-4334-4) carried out by the
Regulatory Studies Program of Mercatus Center at George Mason
University, entitled, ``Over Stressing Business: OSHA and Ergonomics.''
The study included the following statement: ``The draft rule requires
employers to evaluate their ergonomics program according to both
activity and outcome measures. Yet in the case of MSDs, neither
activity nor outcome measures are likely to reflect program
effectiveness.''
The final rule does not require employers to evaluate their
programs for compliance with the standard, as proposed, because this
statement confused commenters and is unnecessary. The final rule's
requirements (paragraphs (u)(1)(ii) and (iii)) that employers
``evaluate the elements of the program to ensure they are functioning
effectively'' and ``assess whether the program is achieving results''
will essentially ensure compliance with the standard and eliminate the
confusion caused by the proposed statement. Further, as the Dow
Chemical Company pointed out, programs may be effective even if they do
not contain every sub-element of the OSHA standard; this is certainly
the case with grand fathered programs that were put in place well
before OSHA's standard was promulgated (Exs. 30-3765 and 32-77-2).
Measures of program effectiveness: Many commenters asked OSHA to
identify measures of program effectiveness that the Agency believes are
appropriate. For example, the Dow Chemical Company stated, ``If OSHA
maintains the requirement to evaluate `effectiveness' of a program,
then it should indicate the method an employer can use for measuring
`effectiveness'. A program may have all the required elements and thus
be in compliance with the rule, but not address all potential MSDs''
(Ex. 30-3765). The Oregon Building Industry Association (Ex. 30-562)
and others (Exs. 30-368, 30-541, 30-627, 30-1697, 30-1717, 30-1355, 30-
1545, 30-3783; 31-334: 32-210-2) raised the same issue, and the Oregon
Association also asked, ``Would the occurrence of an injury allow the
OSHA inspector to automatically qualify the program as not effective?''
(Ex. 30-562).
Organization Resources Counselors, Inc. (ORC) (Ex. 30-3813) voiced
a somewhat different concern regarding the need for measures of
effectiveness. ``OSHA expresses particular concern in the preamble that
there is a need to assure that a demonstration of effectiveness does
not mask under reporting of MSDs,'' they wrote. ORC agreed that this
was a real concern and suggested that employers should be required to
provide evidence that there is an effective early reporting mechanism
in place as a part of their demonstration of program effectiveness. In
response to the views of commenters, OSHA notes that the final rule
identifies a number of measures of effectiveness, including reductions
in the number or severity of MSDs, increases in the number of jobs in
which ergonomic hazards have been controlled, reductions in the number
of jobs posing MSD hazards to employees, or any other demonstrably
appropriate measure of effectiveness, that OSHA believes are indicative
of program effectiveness. This list of measures is not exhaustive; it
is meant to be illustrative only. OSHA is aware that employers with
successful programs use other measures, such as reductions in workers'
compensation costs, increases in the number of early reports of MSD
signs and symptoms, and increases in product quality, to evaluate the
effectiveness of their ergonomics programs (DOD Tr. 3296-3297; OR Ex.
32-78-1 p.22; AFL-CIO Ex. 32-339-1-29; Library of Congress Ex. 32-339-
1-33 p.143; Paper, Allied-Industrial, Chemical & Energy Workers
International Union Local 1202 (PACE) Tr.11206; International Paper Ex.
32-61).
As one rulemaking participant, Organization Resources Counselors
(ORC) (Tr. 4147) stated during testimony about the proposed rule, ''* *
* there are many different ways that companies use to evaluate
effectiveness. While they might all have common elements. . .they apply
those elements in very different ways, depending on the circumstances,
the nature of the work, the employees, and the nature of the
workplace.'' In addition, OSHA does not believe that the ``occurrence
of an injury'' automatically qualifies a program as ``ineffective,'' in
the words of the Oregon Building Industry Association (Ex. 30-562).
OSHA recognizes that, especially in large workplaces in industries with
many problem jobs, MSDs may continue to occur. The final rule takes a
comprehensive view of program effectiveness and emphasizes the
importance of the essential elements of the program and their proper
functioning. In response to ORC's comment about the importance of
ensuring that early reporting is present, OSHA agrees that such
reporting is essential to program effectiveness and has accordingly
built several mechanisms that will ensure early reporting'work
restriction protection, multiple HCP review, hazard information and
reporting'into the final rule.
Who should conduct program evaluations?: The preamble to the
proposal stated that program evaluations may be conducted by those
responsible for carrying out the employer's program, but also noted
that evaluations performed by persons who are not involved in the day-
to-day operation of the program are often even more valuable because
these individuals bring a fresh perspective to the task. They often can
identify program weaknesses that those routinely involved in program
implementation may fail to see (64 FR 65858-65859). OSHA received a
number of comments addressing who should perform the required
evaluations (Exs. 30-2809; 30-115; 30-2387; 30-3826; 32-339-1; 601-x-
1587-2). One commenter cautioned that special care must be taken to
ensure continuity within the program when outside entities perform
successive program evaluations (Ex. 30-2809). This commenter stated,
``It is important to keep records from every evaluation of the
ergonomics program so that mistakes are not repeated * * * if a
different company performs the evaluation, lessons learned from the
previous evaluation may not be recorded * * * It is also important to
ensure that all ``action items'' (issues brought up during previous
evaluations) are resolved and not ignored.''
The American Federation of Government Employees (AFGE) (Ex. 30-115)
suggested that OSHA or some neutral third party was the appropriate
entity for evaluating the ergonomics program because ``management
should not have carte blanche to evaluate their own program.''
Similarly, the American Society of Safety Engineers (ASSE) (Ex. 601-x-
1587-2) commented that the level of expertise needed to perform program
evaluation/third party audits under this standard is outside that which
many organizations are able to provide. Therefore, ``in order to meet
the expected need of consultation services, OSHA should consider
reviewing a system for voluntary third party audit and evaluations, and
work with accredited private sector professional certification bodies,
both public and private recognized registries,
[[Page 68414]]
and membership organizations to ensure that consultants have an
acceptable level of competence.''
The American Association of Occupational Health Nurses (AAOHN) (Ex.
30-2387) cautioned OSHA about the need to protect employee privacy
during the collection and review of program records for evaluation
purposes. The AAOHN pointed out that ``individuals who are not part of
the day to day operation of the program can bring a fresh perspective,
however in any evaluation, the employer should ensure that employees'
privacy is protected.'' For example, the AAOHN noted that a co-worker
brought in to evaluate a program must understand the need for
confidentiality concerning her or his co-worker's personal health
information, if such information is part of the program evaluation.
OSHA agrees with the AAOHN that the privacy of employee medical and
exposure records must be protected at all times, including during a
program evaluation. These records are required to be handled at all
times in accordance with 29 CFR 1910.1020, OSHA's Access to Employee
Exposure and Medical Records standard.
In response to the views of these commenters, OSHA notes that the
proposed rule did not specify who was to perform the required program
evaluations; the final rule also does not limit the employer's choice
of program evaluators. OSHA is aware that employers with effective
programs rely on different individuals, both from within and outside
their organizations, to perform this function and that the results of
doing so are often excellent (see, e.g., Exs. 32-339-1-53, 601-X-1711).
Some programs, such as the one at General Motors, rely on trained
employees in a Joint Ergonomics Team, consisting of union and
management members, to conduct program evaluations (Ex. 32-339-1-53),
while other companies, such as Halliburton, Inc. (Ex. 601-X-1711) rely
on a Board Certified Professional Ergonomist or other outside expert or
organization to carry out their program evaluation. OSHA does not agree
either with those commenters who argued that employers are not choosing
appropriate and qualified program evaluators or that the Agency should
narrow the employer's discretion in this regard. OSHA remains convinced
that different approaches are appropriate in different workplaces and
that employers are best suited to decide who should conduct the
required evaluations. The final rule, therefore, leaves the selection
of evaluators to the employer.
Records review in the context of program evaluation: OSHA
recognizes in the final rule, as it did in the preamble to the proposed
rule (64 FR 65859), that the extent of the evaluation called for by the
rule will vary from one workplace to another, based on the
characteristics and complexities of the work environment. However, the
basic tools of evaluation remain the same from workplace to workplace,
even though their application may vary. These tools, which are basic to
the evaluation of any safety and health program, include:
--Review of pertinent records, such as those related to MSDs and MSD
hazards;
--Consultations with affected employees (including managers,
supervisors, and employees) regarding the ergonomics program and its
problems (if any); and
--Reviews of MSD hazards and problem jobs.
Examples of the records that are often included in such reviews
include the following:
--The OSHA 200 log (if the employer is required to keep a log);
--Reports of workers' compensation claims related to MSDs;
--Reports of job hazard analyses and identification of MSD hazards;
--Employee reports to management of MSDs or persistent MSD signs or
symptoms;
--Insurance company reports and audits about ergonomic risk factors or
MSD hazards; and
--Reports about MSD hazards from any ergonomic consultants engaged by
the employer.
Some employers, especially owners of very small businesses, may
have few of these records and will, therefore have to rely on other,
less formal, methods to assess effectiveness. Small employers generally
place more emphasis on employee interviews and such approaches as
surveys of MSD hazards and problem jobs when they perform ergonomics
program evaluations. Records reviews can yield valuable information on
the effectiveness of an ergonomics program when comparisons are made
from year to year and trends are identified. For example, if an
employer compares the list of MSD hazards identified during consecutive
program evaluations and finds that the number of hazards has decreased
over time, the employer may conclude that the program's job hazard
analysis and control activities have been effective. Similarly, a
reduction in the number of MSDs from year to year suggests that the
program may be effective, although numbers alone sometimes can be
misleading. However, program evaluation also must consider the accuracy
and reliability of the records under review. For example, it is
essential to be sure that the identified trends are real and not the
product of under reporting, loss of interest in the program, or loss of
attention to detail. For example, a downward trend in the number of
MSDs or MSD hazards reported may indicate that employees are being
discouraged from reporting or that the employees performing job hazard
analysis and control are not doing an effective job because they are
not adequately trained to do so.
OSHA received a variety of comments about records review in the
context of program evaluation (Exs. 30-3765, 30-276; 30-546; 30-2846;
30-1726). For example, the Dow Chemical Company argued that the
proposed requirement that employers evaluate different elements of the
program would require them to gather records to support this effort and
would thus impose an undue burden on certain employers. Dow argued,
``depending on the size and makeup of the workplace, a review of all
the proposed records by each workgroup would add undue burden on each
group'' (Ex. 30-3765).
Texas A and M University (Ex. 30-276) also found the records review
associated with program evaluation potentially burdensome. ``Record
keeping is not value-added for the employer or employees. It primarily
benefits the regulatory overseer.'' ElectriCities of North Carolina
Inc. (Ex. 30-546) agreed: ``[These sections] speak of compulsory Record
keeping above and beyond the OSHA 200 log of recordable work place
injuries and illnesses * * *''. The Manufactured Housing Institute (Ex.
30-2846) noted that ``Small business is already overwhelmed with
paperwork requirements and OSHA should avoid adding to that burden.''
The University of Wisconsin Extension (Ex. 30-1726) asked OSHA to
require that all MSD reporting forms be retained by employers for
eventual program review. ``If a standard reporting form is required for
all employees to report MSD problems, signs and symptoms, these forms
should be retained and made part of the program review, to follow up
each form filed during the program evaluation period.''
In response to these concerns about the recordkeeping burden
associated with program evaluation records review, OSHA notes that the
final rule does not mandate that employers review specific records when
conducting their evaluations. In fact, the final rule does
[[Page 68415]]
not mandate records review or require the development of new records of
any kind. This preamble discussion on records review simply recognizes
that reviewing records already maintained by the employer for other
purposes is one way of getting the information needed to evaluate a
program.
The Agency believes that employers are best able to determine which
records in their workplace will provide the most valuable information
for evaluation purposes. For example, in a very small firm that is not
required to keep the OSHA 200 Log, the only records available for
review may be employee reports of MSD incidents, workers' compensation
claim information, and records of Quick Fix controls implemented; some
workplaces may not even have these records. In most workplaces,
however, employers will wish to review a variety of records to identify
trends, evaluate the functioning of each program element, and assess
the overall performance of the program. OSHA's approach is consistent
with that taken by a number of employers who conduct evaluations of
their ergonomics programs, in that it allows employers the latitude to
decide how best to conduct evaluations of their workplaces. The United
Technologies Corp. (Ex. 31-334) agrees that such flexibility is
important: ``It is important to encourage creativity and innovation on
the part of employers in meeting the requirements * * *''. This
flexibility also means, of course, that employers such as The
University of Wisconsin Extension (Ex. 30-1726) who wish to develop
standardized MSD reporting forms to use for evaluation and other
purposes are free to do so.
The proposal contained a requirement that program evaluation
include consultations with employees, and the final rule also includes
such a requirement. Affected front-line employees (or a sample of
them), and their supervisors and managers, must be included in this
process. Consultations with employees elicit information on how well
the ergonomics program has been communicated to the people who rely on
it the most.
Paragraph (u)(2)(ii) of the final rule requires employers to
evaluate the elements of their ergonomics programs to ensure that each
of the elements is working properly. If employees cannot explain what
MSD hazards they are exposed to in the course of their work, do not
know what steps their employer is taking to eliminate or control these
hazards, are unclear about the procedures they should follow to protect
themselves from these hazards, or do not understand how to report MSDs
or MSD hazards, the hazard information and reporting and training
components of the program are not working. If a supervisor is unclear
about how to reinforce proper work practices, the management leadership
and training components of the program are both likely to need
improvement. Similarly, if managers are not aware of the MSDs and MSD
hazards employees are reporting and what corrective actions are being
taken, the management leadership and training components of the
ergonomics program should be improved. Because interviews allow the
program evaluator to assess how the elements individually and the
program as a whole is actually working, there is no substitute for
direct input from employees in the evaluation process.
Program evaluation also must include an assessment of MSD hazards
and the extent to which they are being addressed (paragraph
(u)(1)(iii)). This assessment is concerned not only with identifying
MSD hazards but with identifying how well the ergonomic program is
addressing them. If the program evaluation identifies jobs that have
not been analyzed but exceed the Action Level, the job hazard analysis
component of the program needs to be improved. In addition, if jobs
with previously identified MSD hazards have not been corrected or
prioritized for correction, the evaluator may conclude that the job
hazard control component of the program is not effective. Likewise, if
an MSD hazard is identified and controlled in a problem job in one part
of the facility but the same job has not been controlled in another
part of the facility, several program components may need attention:
the management leadership component, which may have failed to
coordinate and disseminate MSD hazard information throughout the
facility, the training component, which may have failed to provide the
employees performing the job hazard analyses with adequate training,
and the control component, which may have failed to prioritize jobs
appropriately for control.
Paragraph (u)(1) (i)-(iv) establishes the steps employers must
follow to evaluate the effectiveness of their ergonomics programs. It
answers the question, ``What must I do to make sure my ergonomics
program is effective?'' This requirement describes the minimal
evaluation procedures necessary to assess whether or not an ergonomics
program is working as intended. Paragraph (u)(1) of the final rules
reads as follows:
(1) You must evaluate your ergonomics program at least every
three years as follows:
(i) Consult with your employees in the program, or a sample of
those employees, and their representatives about the effectiveness
of the program and any problems with the program;
(ii) Review the elements of the program to ensure they are
functioning effectively;
(iii) Determine whether MSD hazards are being identified and
addressed; and
(iv) Determine whether the program as a whole is achieving
positive results, as demonstrated by such indicators as reductions
in the number and severity of MSDs, increases in the number of
problem jobs in which MSD hazards have been controlled, reductions
in the number of jobs posing MSD hazards to employees, or any other
measure that demonstrates program effectiveness.
Paragraph (u)(1)(i) of the final rules requires employers to
``consult with your employees in the program, or a sample of those
employees, and their representatives about the effectiveness of the
program and any problems with the program.'' Employee participation in
the ergonomics program is critical for success, and the involvement of
employees in program evaluation is just one more way that employees can
take an active role in the program. The requirement that employers
consult with employees regarding program evaluation is not unique to
the final Ergonomics Program standard. OSHA recently promulgated a
similar provision in the Respiratory Protection final rule (29 CFR
1910.134).
Employees in jobs that have been identified as problem jobs are in
the best position to judge whether or not job hazard analysis and
control measures are effectively reducing or eliminating MSD hazards.
Perhaps even more importantly, these employees will be most
knowledgeable about whether the implemented controls have introduced
new, unintended MSD hazards to the job. By consulting with employees,
employers also can have direct feedback on the effectiveness of other
ergonomics program elements, such as opportunities for employee
participation, hazard information and reporting, and training. OSHA is
aware that employers sometimes act in good faith to implement
ergonomics program elements, but that the actual result experienced by
employees can differ markedly from the intention. Thus, by checking
directly with their employees, employers can be sure that their
ergonomics program resources are being effectively invested.
Two rulemaking participants commented that the proposed provision
on employee consultation did not require consultations with anyone
other than employees in problem jobs or allow the employer to select a
subset of
[[Page 68416]]
employees with whom to consult. The Department of Defense (Ex. 30-3826)
commented that, for some employers, such as large companies, branches
of the military, etc., the requirement to consult with employees could
be interpreted to mean consultation with tens of thousands of
employees. As a result, DOD requested that the requirement be changed
in the final rule to allow for representative sampling of employees. In
addition, both the DOD (Ex. 30-3826) and the AFL-CIO (Exs. 32-339-1;
500-218) commented that OSHA had neglected to include employee
representatives in the proposed consultation process. The AFL-CIO
suggested (Ex. 32-339-1) that this provision of the final rule ``should
be modified to provide for consultation with the employee
representative, in addition to employees in problem jobs. This
modification is consistent with the requirement of [the proposed
employee participation provision] which calls for both employees and
employee representatives to be involved in all aspects of the
program.''
After reviewing the record on these points, the Agency has revised
paragraph (u)(1)(i) of the final rule to reflect the concerns of larger
employers and to allow them to consult with employees in the program,
or ``a sample of those employees'' about the effectiveness of the
program and any problems with it. In addition, the final rule states
clearly that designated employee representatives are to be involved in
the consultation process (paragraph (u)(1)(i)). Further, employers are,
of course, free to involve other employees in the consultation process
if they wish to do so; however, OSHA is not requiring that employees
other than those in problem jobs be consulted as part of the evaluation
process.
Another concern raised by the Dow Chemical Corp. (Ex. 30-3765) was
its interpretation that OSHA was attempting in the preamble for this
proposed section to mandate the questions employers must ask in
conducting an evaluation: ``Dow does not believe that OSHA should
mandate the specific questions each employer must ask employees during
this review, which it seemingly tries to do in the preamble at page
65858.'' Dow went on to say, ``Scripted questions may not adequately
uncover issues or concerns and, from the perspective of the employee,
may sound more like an interrogation than a fruitful dialogue.'' OSHA
does not intend the discussion questions included in the preamble to be
mandatory. They are presented to provide employers, and particularly
smaller employers who are less likely than a company like Dow to be
experienced in program evaluation, with ideas about the kinds of topics
an evaluator might find useful when consulting with employees.
Some rulemaking participants (Exs. 30-494, 30-3745, 30-3723, 32-
351-1, 30-4467) argued that employee participation in the evaluation
process might be problematic. They evidently believe that requiring
employers to consult with employees in problem jobs could subject the
employer to citations. For example, the Forum for a Responsible
Ergonomics Standard (Ex. 32-351-1) commented, ``If an employee deems
the program ineffective, but the employer disagrees and implements no
measures to improve effectiveness, the proposal appears to grant OSHA
discretion to cite the employer for non-compliance.'' Morgan, Lewis &
Bockius LLP (Ex. 30-4467) also raised concerns about employee
participation in developing, implementing and evaluating the employer's
ergonomics program: ``The latter is the most troublesome; employers
could conceivably receive citations by virtue of a compliance officer's
subjective determination that employees were not allowed to evaluate
every aspect of the program. Moreover, if employees' suggestions for a
program are rejected, the employer arguably could be said to have
unlawfully limited employee participation in the ``development'' of a
program. (Ex. 30-4467). ``
Three other commenters, the Salt River Project (Ex. 30-710), the
Integrated Waste Services Association (Ex. 30-3853), and Southern
California Edison (Ex. 30-3284), argued that the proposed provision to
consult with employees during evaluations was too open to subjective
interpretation: ``The final standard should make clear that the
employer is not required to act on a recommendation from employees if
the employer can document that the recommendation is without merit''
(Ex. 30-3284).
In response to these comments, OSHA notes that, in the Agency's
experience, employee input is invaluable; employees are the best source
of information on how a program is working in practice. However,
employers are expected to use their judgment and to assess the value of
any information they receive in the course of an evaluation, whether
from a records review or employee consultations. Weighing input from
many sources is standard management practice, and the rule anticipates
that employers will continue to use their judgment in these matters.
Further, OSHA intends employee participation in the ergonomics program
to be active and meaningful, but this does not mean, as Morgan, Lewis &
Bockius suggest, that they must be allowed to evaluate ``every aspect
of the program'' (Ex. 30-4467).
Paragraph (u)(1)(ii) of the final standard requires employers to
``review the elements of the program to ensure they are functioning
effectively.'' This requirement is nearly identical to the
corresponding provision proposed. OSHA received a few comments on this
proposed provision (see, e.g., Exs. 30-3031, 30-3813, 30-4334). Tesco
Drilling Technology Inc. (Ex. 30-3031) stated: ``If OSHA does in fact
believe that employers are best able to determine evaluation criteria,
and that employers should be able to define ``functioning properly,''
why is OSHA proposing this cumbersome standard to begin with? If there
is no specific evaluation criteria or goal in each element, how can a
compliance officer issue a citation for noncompliance in any portion of
the program?'' Organization Resources Counselors, Inc. (ORC) (Ex. 30-
3813) stated that the phrase ``functioning properly'' was vague, and
comments received from Senator Bond, Chairman of the United States
Senate Committee on Small Business (Ex. 30-4334), agreed with those of
ORC: ``For an employer to evaluate its ergonomics program, it is to
``evaluate the elements of [its] program to ensure they are functioning
properly; and evaluate the program to ensure it is eliminating or
materially reducing MSD hazards * * * The use of these terms, and
others, throughout the proposed standard means that employers will be
left to their own instinct and resources to decide whether they have
met the obligations and gone far enough.''
OSHA's reason for including this provision in the final rule is
that evaluations of individual elements and their functioning often
reveal program deficiencies that are undermining program effectiveness
but could be difficult to detect if the employer only evaluated the
program as a whole. For example, if employees are not reporting MSD
hazards, it may mean that the management leadership and training
components are not working properly. The final rule thus continues to
require that employers evaluate each program element as well as the
program as a whole. How this is done is left to employers, because the
records, methods to be used, and cultures of workplaces differ markedly
and no one approach is appropriate for all. The final rule does not
include specific effectiveness measures for each element of the
program, because these would vary extensively from one workplace to
another. However, as commenters
[[Page 68417]]
recommended, the final rule does include examples of effectiveness
measures that are useful in evaluating the effectiveness of programs as
a whole.
Paragraph (u)(1)(iii) of the final rule requires employers to
``determine whether MSD hazards are being identified and addressed.''
The primary purpose of implementing an ergonomics program is the
identification and control of MSD hazards. OSHA expects employers to
establish evaluation criteria to assess the success of their program in
meeting this goal. There are a wide variety of methods available to
employers, ranging from a simple count of the number of problem jobs
controlled to more sophisticated analyses, such as year-to-year trend
analyses.
Again, OSHA finds that employers are best able to determine the
specific evaluation criteria that will most effectively tell the story
of their efforts to identify and address MSD hazards. Commenting on the
corresponding proposed paragraph, which would have required employers
to evaluate their program to ensure it is ``eliminating or materially
reducing'' MSD hazards, Milliken & Company (Ex. 30-3344) and others
(Exs. 30-3749, 30-4674) argued that the proposed provision would
require an evaluation to ensure that the program is eliminating MSD
hazards, when a better measure might be the extent to which the program
is reducing the incidence of MSDs. Nucor Corporation and Vulcraft-South
Carolina (Exs. 30-3354, 30-3848, 30-4799, 30-4540, 601-x-1710) asked
OSHA to add ``to the extent feasible'' to this provision on the grounds
that doing so ``would keep the proposed regulation consistent in its
requirements throughout all elements of an ergonomics program.''
The Dow Chemical Co. (Ex. 30-3765) asked OSHA to modify this
paragraph in the final rule by adding specific language at the end of
the paragraph to read, ``or maintaining the risks at an acceptable
level.'' In Dow's view, such a change would make it clear that
instituting the same ``fix'' across the board may not eliminate all MSD
injuries. Dow also was unclear about what the Agency meant by
``materially reducing'' MSD hazards.
The National Telecommunications Safety Panel (Ex. 30-3745)
expressed similar concerns about the proposed phrase ``eliminating or
materially reducing MSD hazards.'' The Panel argued that this language
was misleading because, ``some MSDs exist epidemiologically in any
workplace.'' SBC Communications Inc. (Ex. 30-3723) urged OSHA to delete
the term ``eliminating or materially'' from the final rule because its
use failed to recognize ``that some MSDs may exist epidemiologically in
any workplace and that the program [envisioned by the standard] is
realistic and performance-based.''
Footwear Industries of America Inc. (Ex. 30-4040) commented that
the inclusion of the proposed ``eliminating or materially reducing''
phrase suggested that ``employers will meet their obligations if they
select and implement the controls that a reasonable person would
anticipate would achieve a material reduction in the likelihood of
injury. `` However, according to this commenter, ``the ``reasonable
person'' standard is hardly a bright-line test and provides excessive
enforcement discretion to OSHA inspectors when determining
compliance.''
OSHA has revised many provisions of the final rule in response to
comments received and data submitted to the record. One of the more
important changes is the revision to the language of paragraph (k),
which tells employers what they must do to achieve compliance with the
final rule's control requirements. The final rule no longer uses the
phrase ``materially reduce,'' and paragraph (u)(1)(iii) therefore has
been revised as well. The language of this provision now requires
employers to ``determine whether MSD hazards are being identified and
addressed.'' OSHA believes that this language is responsive to the
concerns of those employers who interpreted the proposed language to
mean that all MSD hazards had to be eliminated before an ergonomics
program could be judged effective. The final rule, at paragraph (k),
makes clear that OSHA will consider an employer to be in compliance
with the standard's control requirements when it has implemented
controls meeting any of the endpoints identified in that paragraph.
There are clearly many ways to assess whether the program is
identifying MSD hazards and dealing with them appropriately, as
discussed above, and any method that is appropriate and accurate in
making this assessment is acceptable to OSHA.
A number of rulemaking participants ( Exs. 32-182, 32-111-4, 30-
167, 30-3826, 32-210-2, 32-85-3, 30-3686, 30-3826, Tr. 9088, Exs. 30-
3284, 30-240, Tr. 16578, Exs. 32-339-1, 500-218, 31-307, 30-3860, Tr.
8982, Tr. 4372, Exs. 30-1726, 30-1726) commented that OSHA would
clarify the proposed evaluation requirements significantly if it
developed guidance materials and model evaluation tools for employers.
For example, Organization Resources Counselors (ORC) (Ex. 30-3813) made
comments that were representative of those of the above group when it
asked OSHA to include a non-mandatory appendix of types of performance
measures and approaches that OSHA would consider appropriate. In
addition to the measures of effectiveness mentioned by OSHA in the
proposed preamble, such as decreases in the numbers or rates of MSDs
and decreases in severity, ORC suggested a few others: ``Measures might
include reduced workers' compensation claims for MSDs, use by the
employer of periodic symptoms surveys and other indicia of effective,
early reporting, or demonstration that risk factors have been reduced
and/or tools and equipment have been modified.''
Two other commenters, the American Federation of State, County and
Municipal Employees (AFSCME) (Ex. 32-182) and the United Steelworkers
of America (Ex. 32-11-4), argued that such tools were necessary. They
criticized the proposed evaluation provisions in general, because they
failed to provide any criteria to aid employers in determining if their
ergonomics programs were effectively eliminating or materially reducing
MSDs. The American Association of Occupational Health Nurses (AAOHN)
(Exs. 30-3686, 30-2387) also urged OSHA to assist employers by
providing standardized evaluation forms.
OSHA agrees that providing employers with evaluation tools and
forms would be helpful to employers, employees, and OSHA Compliance
Officers. In the period between publication of the final rule and the
compliance dates for program evaluation, the Agency plans, if resources
permit, to develop and disseminate such materials.
AM Moving and Storage Association (Ex. 500-82) argued that the
standard as a whole would be infeasible for its member companies: ``if
it is not feasible for movers to implement controls that would
eliminate and materially reduce MSD hazards, then it is equally
impossible for moving and storage companies to monitor and track the
progress of the proposed ergonomics program.'' OSHA is not, in this
standard, requiring employers to implement infeasible controls or to
reach infeasible hazard control endpoints. Instead, OSHA is requiring
employers to take reasonable measures to protect their employees from
MSD hazards. OSHA expects that moving companies also will find
effective ways of reducing the number and severity of their MSD
hazards.
[[Page 68418]]
The Union of Needletrades, Industrial and Textile Employees (UNITE)
(Ex. 32-198-4) argued that the proposed evaluation section would be
ineffective. They commented that the proposed evaluation requirements
overall were too narrow and ``must be expanded to determine actual
effectiveness of the existing program.'' OSHA agrees, and has expanded
the final rule's evaluation requirements to include a requirement that
employers assess their programs using indicators of effectiveness, such
as reductions in the number, rate, or severity of MSDs. OSHA believes
that the final rule's combination of qualitative and quantitative
approaches to program evaluation will ensure the effectiveness of the
programs implemented to comply with this rule.
Paragraph (u)(2)--Program Evaluations at More Frequent Intervals
Triggered by Events
Paragraph (u)(2) of the final rule requires an employer to evaluate
the program, or a relevant part of it, when the employer has reason to
believe that the program, or an element of the program, is not
functioning as intended; when operations in the workplace have changed
in a way that is likely to increase employee exposure to ergonomics
risk factors and MSD hazards on the job; and, at a minimum, once every
three years. Thus, the final rule retains the minimum 3-year evaluation
frequency proposed but provides greater specificity than did the
proposal about the events that trigger evaluation at more frequent
intervals.
The proposed language on the frequency of program evaluation, which
required employers to evaluate their programs ``periodically, and at
least every 3 years,'' was performance-based rather than specific
because of the diversity of workplaces covered by the rule. OSHA
defined periodically in the proposal as a process or activity that is
``performed on a regular basis that is appropriate for the conditions
in the workplace'' and ``is conducted as often as needed, such as when
significant changes are made in the workplace that may result in
increased exposure to MSD hazards.'' Thus, the proposed provision on
the frequency of required evaluations was designed to reduce
unnecessary burdens on employers whose workplaces, for example, changed
little over time, while ensuring that program evaluations, which are
essential to program effectiveness, were conducted at some minimal
frequency. The final rule reflects the same principles but has been
revised to provide the additional specificity requested by commenters.
OSHA continues to believe, as explained in the proposal, that the
employer is in the best position to determine how often the ergonomics
program at a particular work site needs to be evaluated to ensure its
effectiveness. A site undergoing process or production changes, for
example, or one experiencing high turnover, may need more frequent
evaluations than other, less dynamic, workplaces. Workplaces with these
characteristics are addressed by final rule paragraph (u)(2), which
requires employers faced with changes in operations that are likely to
increase employee exposure to evaluate their programs when such changes
occur. Similarly, an increase in the number or severity of MSDs in the
workplace would suggest that a program evaluation is warranted. This
situation is one that would be covered by paragraph (u)(2) of the final
rule; such an increase clearly suggests that the program, or a part of
it, has failed to operate properly. In work environments with a stable
workforce and work operation, program evaluations conducted once every
three years may be sufficient. For these workplaces, the minimum
frequency required by paragraph (u)(1) may apply.
As noted in the proposal, current industry practice as to the
appropriate frequency of ergonomics program evaluations in specific
environments is available from other sources. For example, the
Meatpacking Guidelines (Ex. 2-13) recommend semi-annual reviews by top
management to evaluate the success of the program in meeting its goals
and objectives. In addition, a wide range of companies with successful
ergonomics programs evaluate these programs at regular intervals.
Paragraph (u)(3)--Correcting Program Deficiencies
Paragraph (u)(3) of the final rule requires employers to correct
any deficiencies identified by the evaluation. It also requires that
employers correct such deficiencies promptly. Deficiencies are findings
that indicate that the ergonomics program is not functioning
effectively because, for example, it is not successfully controlling
MSD hazards or is not providing needed MSD management. OSHA requires
employers to respond to deficiencies in the ergonomics program by
taking actions such as: identifying corrective actions to be taken;
assigning the responsibility for these corrective actions to an
individual who will be held accountable for the results; setting a
target date for completion of the corrective actions; and following up
to make sure that the necessary actions were taken. In a very small
workplace, of course, such detailed planning would likely not be
necessary.
Some commenters, including Milliken & Company (Ex. 30-3344) and
(Exs. 30-3749; 30-4674), stated that the proposed requirement to
correct program deficiencies discovered during an evaluation would
create a ``needless second tier of violations on top of the underlying
substantive requirement that is not being met.'' Moreover, they argued
that, ``the requirement to promptly take action to correct deficiencies
does not provide sufficient latitude for employers to implement
corrections within a time frame that will be reasonable in every
case.'' Tesco Drilling Technologies (Ex. 30-3031) also expressed
concern about an employer's liability once program deficiencies have
been identified. Tesco asked, ``What are the criteria by which a
compliance officer can issue a citation under this provision. * * * If
a citation can not be issued, how can this be enforced? If it cannot be
enforced, how can it be a rule?''.
In response, OSHA wishes to emphasize that its primary goal is to
protect employees from MSD hazards, not to hold employers liable for
ergonomics program deficiencies. OSHA expects that even the best
programs will find deficiencies in their ergonomics program at one time
or another. OSHA's concern is whether or not the employer has acted on
the information obtained during the program evaluation and is taking
steps to correct the problems identified. Employers who act in good
faith to correct identified program deficiencies clearly will satisfy
this requirement. However, employers who identify ergonomic program
deficiencies through the evaluation process and then do not act on this
information may not be in compliance with this requirement.
The final rule does not specify the time frame within which
identified program deficiencies must be corrected. The Agency
recognizes that the time needed to correct a program deficiency will
vary according to many factors. For example, the following factors may
influence an employer's response time:
--The nature of the MSD hazard;
--Previous attempts to correct the problem;
--The complexity of the needed controls;
--The expense of the needed controls;
--Whether the hazard is a higher or lower priority in the list of
identified program deficiencies; and
--The expertise needed to control the hazard.
[[Page 68419]]
Some rulemaking participants (Exs. 30-3853, 30-3765, 30-710, 30-
240) commented that OSHA was not clear about what kind of program
deficiencies needed correction or what ``as quickly as possible''
meant. Edison Electric Institute's (EEI) comment (Ex. 30-3853) was
representative of the views of those commenters concerned about the
time frame for correcting deficiencies: EEI stated that the proposed
requirement to correct ergonomics program deficiencies ``as quickly as
possible'' was vague and unenforceable. August Mack Environmental Inc.
(Ex. 30-240) stated that, in many cases, the responsibility for
correcting deficiencies found will be transferred to a program
administrator, who may be so overwhelmed with other duties, including
those of the ergonomics program, that he or she may not be able to
respond in a reasonable period of time. ``My concern is that a
deficiency may be found and assigned to the program administrator who
will work the problem into his or her overall priority system, so that
it can be fixed,'' August Mack posited. ``However, if inspected in the
meantime, OSHA will find that this is not responsive enough.''
Again, OSHA's aim in including program evaluation requirements in
the final rule and in requiring deficiencies identified through
evaluation to be corrected promptly is not to catch employers in
violations but to ensure that the employer's ergonomics program is
working correctly. If employers have identified deficiencies, corrected
those that can be addressed quickly and easily, prioritized those
requiring longer to correct, and are making reasonable progress in
addressing prioritized deficiencies, they likely will be in compliance
with these requirements.
The Dow Chemical Company (Ex. 30-3765) argued that the proposal was
unclear as to what program deficiencies were being addressed. ``Dow
simply does not understand whether the evaluation in this section is
the same evaluation of the program required in other sections as an
employer deals with identified problems or whether it is an evaluation
of the program addressing every element of this regulation. If it is
the first case, then the section is redundant and should be removed. If
it is the latter case or both, then the Preamble and section should be
rewritten to clearly explain this.'' OSHA is unclear about the meaning
of Dow's comment, but believes that the final rule's clear requirements
for program evaluation will shed light on the issues of concern to
them.
Dow (Ex. 30-3765) also voiced concern that the proposed evaluation
section seemed, in their opinion, to unfairly shift the burden of
correcting program deficiencies to the employer without considering the
employee's contribution to such deficiencies. Dow argued that the
burden of correcting deficiencies should not be placed completely on
the shoulders of the employer. ``Because ergonomics is focused on how
an individual interacts with his or her workplace, Dow believes that
the employee must have some responsibility for making appropriate
changes in their activities.'' Dow suggested that OSHA include an
``Employee Responsibility'' section in the final standard that would
state that if employees are not following what they are supposed to do
under the rule, their employers will not be cited for violating this
standard.
OSHA disagrees with Dow's views in the matter of employee
responsibilities. It is the employer, not the employee, who controls
the conditions of work. If an employee, as Dow's comment suggests, is
not observing appropriate work practices, it is the employer's
responsibility to compel compliance. Employers must manage the
conditions in their workplace; they must lead by example, train their
employees in the use of controls and safe work practices, reinforce
such practices, and, if necessary, establish a disciplinary system so
that employees understand that they must follow safe and healthful
practices on the job. However, OSHA does not believe that employers
must be the ``insurers'' of their employees' behavior. If, for example,
an employer establishes, implements, trains employees in, and enforces
safe work practices, and does so in a consistent manner, the employer
will not be liable for an employee's unforeseeable violation of its
safety rules.
In contrast to those commenters who found the proposed provisions
vague, some commenters found the proposed evaluation requirements too
specific. For example, the Eastman Kodak Company (Ex. 30-429) argued
that only the proposed basic obligation should be included in the final
rule and that the specific requirements should be deleted: ``We believe
. . . [these requirements address] general management practices that
should not be mandated but should be provided in a non-mandatory
appendix.''
OSHA believes that the final rule's provisions provide employers
with the steps to follow to conduct an effective and efficient program
evaluation. Absent such provisions, many employers, particularly
smaller ones, would not know how to conduct an evaluation. Accordingly,
the final rule includes paragraphs (u)(1) and (2), which mandate
certain evaluation steps and procedures and establish the minimal
frequencies of periodic program evaluations. Many employers, however,
such as Kodak, who have had ergonomics programs for years, are unlikely
to need such direction.
The Labor Policy Association, Inc. (LPA) (Ex. 30-494), the
Department of Defense (Tr. 9085-9086) and ( Ex. 30-3781) cautioned OSHA
about the difficulties that could arise from doing a program evaluation
shortly after creating a new ergonomics program. Specifically, the LPA
argued that ``newly implemented ergonomics programs typically
experience a spike in reported MSDs that at some point levels off and
begins to drop. However, it can take as long as four years before the
drop starts to occur. Under the standard, an employer whose reported
MSDs were increasing would be required to implement different
mechanisms to correct the program's deficiencies. However, an OSHA
compliance officer could view this as evidence of an ineffective
ergonomics program and launch an in-depth compliance review, even
though the increase in MSDs is a natural outcome of having a new but
effective program.'' Similarly, the DOD argued that time must be
allowed to elapse for ergonomics programs to gather data needed for
evaluations.
OSHA is fully aware that the number of MSDs reported may increase,
and often substantially, in the first year or so after program
implementation. The Agency believes that the examples of effectiveness
measures OSHA includes in final paragraph (u)(1)(iv) are sufficiently
varied to be suitable for workplaces with programs at various stages of
maturity.
Finally, the UFCW (Ex. 32-210-2) asked OSHA to require employers to
respond to and, if warranted, address issues raised by employees during
a program evaluation. ``The employer should be required to take action
to reduce or eliminate hazards uncovered by an evaluation based upon
employee concerns. This type of response and evaluation will only serve
to strengthen the entire ergonomics program by building confidence
among employees that they are a valuable source of information and also
can be part of the evaluation process.'' OSHA believes that employers
will respond to employee concerns during evaluations when they seek
inputs from them about the effectiveness of the program. To do
otherwise would be inefficient as well as non-responsive. This does not
mean, of course, that employers must respond to all employee
suggestions, as some commenters feared (see, e.g., Exs. 30-
[[Page 68420]]
3284, 30-3853, 30-710). Because OSHA believes that such two-way
communication will be encouraged by the final rule's evaluation
provisions, the Agency has decided not to mandate such responses in the
final rule's program evaluation provisions.
Paragraph (v)--What Is My Recordkeeping Obligation?
The final recordkeeping provisions specify that employers (except
those with fewer than 11 employees) must keep those records essential
to any effective ergonomics program. OSHA observed in the proposal (64
FR 65861) and continues to be convinced that occupational injury and
illness records are a vital part of an effective ergonomics program in
all but the very smallest establishments. Records provide employers,
employees, and consultants with valuable information on conditions in
the workplace and can be used to identify trends over time and to
pinpoint problems. However, OSHA also continues to recognize the need
to reduce paperwork burdens for all employers, especially small
employers, to the extent that this can be done without reducing safety
and health protections. OSHA proposed to limit both the kinds of
records employers were required to keep and the applicability of the
standard's recordkeeping requirements to very small employers. With
very few changes, the final rule contains the recordkeeping
requirements that were proposed. OSHA believes that the approach to
recordkeeping in the final rule is consistent with the Paperwork
Reduction Act's emphasis on minimizing paperwork burdens for small
employers whenever possible.
Because larger employers have more complex workplace organizations,
OSHA proposed that larger employers would be required to keep records
of employee reports of MSDs and the employer's responses to them; the
results of job hazard analyses; records of Quick Fix controls; records
of controls implemented in problem jobs; program evaluations; and
records of the MSD management process. OSHA proposed to exempt
employers with fewer than 10 employees from the standard's
recordkeeping requirements because in these very small workplaces,
information can be communicated and retained informally. The final rule
requires that employers with ergonomics programs keep the same records
as those proposed. However, the final rule expands the recordkeeping
size threshold from 10 employees to 11 employees. This expansion will
make the recordkeeping size threshold for this rule consistent with
that for OSHA's recordkeeping rule (29 CFR Part 1904).
The following paragraphs discuss the specific requirements of the
recordkeeping provisions of the final ergonomics rule and the comments
OSHA received in response to the proposed recordkeeping requirements.
OSHA has carefully evaluated participants' comments concerning the
records needed for effective ergonomics programs to assure that the
final standard only requires employers to keep those records that are
necessary, i.e., those records that have utility to employers,
employees, and OSHA.
Paragraph (v) of the final rule, entitled ``What is my
recordkeeping obligation?'' establishes which employers must meet the
rule's requirements for recordkeeping. This provision requires
employers with more than 10 employees at any time during the previous
calendar year to keep records of their ergonomics program. Employees to
be counted toward this total include part-time and seasonal employees
and employees provided through personnel services. Under the proposed
rule, employers with fewer than 10 employees would have been exempt
from having to keep any ergonomics program-related records. As noted
above, the final rule increases this size threshold to ``more than 10
employees.'' OSHA's experience indicates that, because of the absence
of management layers and multi-shift work, informal communication may
be used in very small companies, and formal recordkeeping systems may
not be necessary. A very small establishment may have a very simple and
informal, but nevertheless effective, ergonomics program that does not
need written records.
OSHA proposed, and the final rule includes part-time and seasonal
employees and employees provided through personnel services when they
count the number of employees they employed at any time during the
previous year. As explained in the proposed preamble (64 FR 65861),
these part-time and temporary employees are retained and supervised by
the employer on a daily basis even though this may be the case only for
a limited time. As discussed above, establishments with more than 10
employees generally should be required to keep records because they are
likely to have more than one layer of management and therefore need to
have written procedures. In addition, if these employees were not
counted toward the size threshold for recordkeeping, large workplaces
that operate with few permanent employees but numerous temporary
employees (an organizational structure that is increasingly common)
would not be required to keep records despite several levels of
management and more formal methods of communication.
The proposed rule's exemption for very small employers elicited
several comments. These comments addressed the usefulness of the
standard's small business recordkeeping exemption and argued that part
time, seasonal, or leased employees should not be included in the count
of employees that triggers recordkeeping. In addition, the Department
of Navy commented on the future applicability of the standard to
federal facilities.
Usefulness of the small business recordkeeping exemption. Some
rulemaking participants (see, e.g., Exs. 30-2493, 3596; Tr. 2982-83,
Tr. 8394, Tr. 15522, Tr. 15565) argued that the proposed small business
exemption would not be useful to small businesses because small
employers would choose to keep records anyway. For example, the
National Federation of Independent Business (Ex. 30-3596, pp. 4-5)
stated that
OSHA has touted its paperwork exemption and ``quick fix''
alternatives to the full ergonomics program requirements as
provisions in the ergonomics standard that were revised to appease
small business concerns. Although a ``paperwork exemption'' may
appear to help on its face, a small-business owner would be ill-
advised not to write down and keep records of everything related to
their ergonomics program when faced with the constant possibility of
an OSHA inspection.
This comment echoes statements made by the small entity representatives
who participated in the Small Business Regulatory Enforcement Fairness
Act (SBREFA) panel for this rule. These representatives maintained that
they would choose to keep records even if they were not required by the
standard to do so (Ex. 23). In response to these small business
commenters, OSHA notes that employers are always free to keep any
records that they wish to maintain, but the final rule does not require
them to do so.
Part-time workers should not count toward the total. Some
rulemaking participants (see, e.g., Tr. 3324, Tr. 5638-39) indicated
that the provision describing which employers must keep records needed
to be clarified and simplified to state explicitly that seasonal,
leased, and part-time employees should be included in the total count.
Other commenters (see, e.g., Exs. 30-240, 429, 1090) felt that the
inclusion of temporary, seasonal, and part-time employees in the count
of employees was burdensome or
[[Page 68421]]
unnecessary. For example, The Eastman Kodak Company (Ex. 30-429, p. 8)
remarked that
This creates significant difficulties in that the prior health
histories of such workers are unknown to the contracting employers
and initial health checks are usually not conducted. Personnel
service workers could have pre-existing conditions that could become
aggravated without MSD factors being present in their workplaces.
OSHA's rationale for including these employees is that it is the
number of employees, not the duration or kind of employment
relationship they have with the employer, that necessitates the keeping
of records. The size of the workforce is the factor that makes layers
of management and more formal methods of communication (and therefore
recordkeeping) necessary. In fact, supervising part-time or leased
employees often adds considerable complexity to management planning,
oversight, and recordkeeping. Thus, the final rule uses a workforce of
more than10 employees on any day of the previous calendar year as the
size threshold that triggers compliance with the rule's recordkeeping
requirements.
Applicability to federal facilities. In a comment unique to federal
agencies, the U. S. Department of Navy (Ex. 30-3818, p. 2) recommended
that OSHA ``acknowledge the different recordkeeping requirements for
federal agencies and rewrite * * * [the standard] to include provisions
for the federal facilities recordkeeping program of 29 CFR 1960.'' OSHA
has considered this request, but has decided that a separate provision
stating the applicability of the rule to federal facility recordkeeping
programs is unnecessary because this matter is better addressed in a
compliance directive for affected federal agencies.
Paragraph (v) of the final rule, which corresponds to section
1910.940 of the proposed rule, establishes the final rule's
requirements for keeping the records required by the standard. It
specifies which records employers must keep and how long they must keep
them. OSHA proposed that employers required by the standard to keep
records maintain the following:
Employee reports of MSDs and the employer's responses to
these reports,
II The results of job hazard analyses and Quick Fixes,
II The controls implemented to reduce or eliminate MSD hazards,
II The MSD management process, and
II The results of ergonomics program evaluations.
OSHA also proposed that most ergonomic program records be retained
by the employer for 3 years or until replaced by an updated record, and
the final rule mandates the same retention periods. The final rule,
like the proposal, makes an exception to the 3-year retention period
for MSD management records. These records are required to be maintained
for the length of the injured employee's employment plus 3 years, a
retention period considerably shorter than that required for other
OSHA-mandated medical records. OSHA health standards, for example,
generally require exposure records to be kept for 30 years and medical
surveillance records to be kept for the duration of employment plus 30
years, as required by 29 CFR 1910.1020, OSHA's access to employee
exposure and medical records standard. These lengthy retention periods
are appropriate for many toxic substances and harmful physical agent
standards because of the long latency between exposure on the job and
the onset of disease. However, since the latency period for most
musculoskeletal disorders is shorter than is the case for many of the
chronic conditions and illnesses covered by other OSHA rules, the
Agency believes that a shorter retention period is appropriate for the
ergonomics rule. Also, changes in the workplace, such as equipment or
process changes, often make older ergonomics records irrelevant to
current jobs and the present workplace environment. Employers'
ergonomics programs continue to evolve, with records of the most recent
aspects of that evolution being the most relevant for employee
protection.
The proposed recordkeeping provisions elicited several comments.
Commenters addressed the following issues: the potential burden imposed
by the recordkeeping requirements; the kinds of records employers
should keep; the appropriate retention period for program-related
records; the need to permit employees and designated representatives to
access the records; and electronic recordkeeping. The paragraphs below
discuss the comments; OSHA's responses to the comments follow this
discussion.
Several rulemaking participants agreed with OSHA's proposed
recordkeeping requirements (see, e.g., Exs. 32-339-1, 182-1; Ex. 500-
206; Tr. 3488). Typical of the views of these commenters was the
comment of the AFL-CIO (Tr. 3488) ``The recordkeeping provisions of the
rule * * * are necessary for the effective implementation of the
program.''
Recordkeeping requirements are burdensome. A number of rulemaking
participants (see, e.g., Exs. 30-74, 294, 429, 526, 544, 546, 652, 653,
710, 1070, 1090, 2428, 2433, 2807, 2991, 3284, 3336, 3367, 3557, 3593,
3723, 3745, 3765, 3770, 3781, 4134, 4184, 4185, 4628, 4839; Exs. 32-77-
2, 300-1; Exs. 500-7, 16, 113, 130, 145, 163; Tr. 3136-37, Tr. 5039,
Tr. 5334-35, Tr. 5493, Tr. 5638, Tr. 9207-9209, Tr. 12198-99, Tr.
12770, Tr. 12860, Tr. 16486-87, Tr. 16491, Ex. 500-163) argued that the
proposed recordkeeping requirements were excessive, burdensome and
unnecessary. For example, a commenter for Owens Corning (Ex. 500-163,
p. 7) stated that
The recordkeeping requirements in the proposed standard are
excessive and poorly defined. In addition, the implied documentation
requirements of the proposed standard are inconsistent with the
requirements of * * * [the proposed rulemaking section], i.e., the
real recordkeeping requirements are much more extensive than those
specifically required by this section.
OSHA also received numerous pre-and post-hearing form letters to
the effect that the proposed recordkeeping section was burdensome or
unnecessary (see, e.g., Exs. 30-2252, 2251, 2360, 4226, 4748, 0382,
2973, 2224, 0591, 0422, 1126, 4684, 4794, 2246, 0382, 2747, 3331, 2244,
2337, 2888, 3517, 0176, 2902, 639, 2874, 4624, 3090, 0070, 2794, 5104,
4402, 1073, 2999, 2033, 2097, 2345, 1304, 2908, 4404, 5187, 4718, 2354,
2359, 4269, 4690, 691, 3201, 3400, 2866, 0597, 1806, 0912, 4605, 2343,
2130, 4422, 1931, 2258, 2998, 2827, 0378, 2342, 2939, 2298, 4946, 2787,
3403, 3293, 2938, 2450, 1672, 2995, 4440, 4944, 2317, 4446, 2853, 0569,
2877, 2994, 2953, 2096, 3130, 1603, 2763, 2885, 3451, 1026, 2884, 2924,
4795, 0455, 2336, 0433, 2197, 1540, 2758, 4796, 2972, 2858, 3294, 4416,
2971, 4798, 4432, 1085, 4657, 2755, 5098, 3982, 5080, 5057, 5053, 2977,
2979, 5009, 3852, 5070, 2978, 3970, 4768, 3983, 4806, 2469, 3971, 3935,
5075, 5078, 2974, 2980, 4802, 2976, 3005, 2975, 2981, 5026, 3798, 2982,
2526, 2285, 3995, 4785; Exs. L30-4958, 4964, 4967, 5211; Exs. 601-X-
249, 419, 1298; Exs. 500-1-224, 225, 226, 228, 229, 230, 231, 232, 233,
234, 235, 236, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 249,
250, 251, 252, 253, 254, 255, 256, 257, 259, 260, 261, 262, 263, 264,
265, 266, 267, 268, 269, 270, 271, 272, 273, 273, 274, 275, 276, 277,
278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291,
292, 293, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305,
306, 307, 309, 310, 311, 312, 313, 314, 315, 316, 318, 319, 320, 321,
322, 323, 324, 325, 326, 327, 328, 329, 331, 332, 333, 334, 335, 336,
337, 338, 339, 340, 341, 342, 343,
[[Page 68422]]
344, 345, 346, 347, 348, 349, 350, 351, 352, 353, 354, 355, 365, 366,
367, 368, 369, 370, 371, 387, 388, 389, 390, 391, 392, 393, 394, 395,
396, 398, 399, 400, 401, 402, 403, 405, 406, 407, 408, 409, 410, 411,
412, 414, 415, 416, 417, 418, 419, 420, 421, 422, 423, 424, 425, 426,
427, 428, 429, 430, 431, 432, 433, 434, 435, 436, 437, 438, 439, 440,
441, 453, 456, 459).
Some proposed records are not required. Some rulemaking
participants questioned the need to keep certain of the records OSHA
proposed that employers retain (see, e.g., Exs. 32-3004, 30-294, 30-
494, 30-2433, 30-1294, 30-3356, 30-4628, 500-177-2). These commenters
argued that the OSHA Log, medical records, and program evaluations were
all that were needed (Ex. 32-300-1), that Quick Fix records were
unnecessary (Exs. 30-294, 30-494, 30-2433), that records of
``preventive'' or ``voluntary'' work restrictions should not have to be
kept (Exs. 30-1294, 30-3356, 30-4628, Ex. 500-177-2), and that employee
reports of MSDs or their signs and symptoms were not needed (Ex. 30-
2433).
The reasons given by these commenters varied. For example, the
Edison Electric Institute (Ex. 32-300-1) believes that only a few
records are needed for effective programs: ``The current required
recordkeeping records including the OSHA 200 Log and medical records
along with the program evaluation should be sufficient to maintain a
current and effective ergonomics program.'' The Exxon-Mobil Corporation
saw no value in keeping records of employee reports of MSDs (Ex. 30-
2433, p. 4), stating that
The [proposed] standard calls for detailed records of job hazard
analyses and hazard control tracking which establishments do not
normally maintain. For example, if a computer monitor is raised 2
inches by use of a monitor block, that action--and any subsequent
adjustment to the height--must be documented and the document
retained. Furthermore, most of the records OSHA proposes to be
maintained are not necessary for an ergonomics program. OSHA should
revisit the recordkeeping requirements and remove the requirements
for employee reports and responses, and quick fix controls.
The Dow Chemical Company (Ex. 30-3765) saw no value in keeping
records of job hazard analyses for 3 years: ``Job hazard analyses
should only be kept while the employer is working through solutions to
reduce the risk of the hazard to an acceptable level.''
The appropriate retention period. The proposed 3-year retention
period also elicited several comments; commenters suggested periods
ranging from 90 days to more than 30 years. Several rulemaking
participants (see, e.g., Exs. 30-297, 3913, 4538; Exs. 32-85-3, 339-1,
(185-3-1); Tr. 3488) stated that the standard's record retention
periods should be set at five years in the final rule, to be consistent
with the retention period for the Log of Injuries and Illnesses and
related records found at 29 CFR 1904.6. The Dow Company commented that
the proposed retention periods were too long, arguing that ``[t]here is
no safety or health reason for keeping records beyond their
usefulness'' and recommending that job hazard analyses ``should only be
kept while the employer is working through solutions to reduce the risk
of the hazard to an acceptable level.'' (Ex. 30-3765, p. 116) August
Mack Environmental Inc. agreed that the proposed 3-year retention
period was appropriate, without providing additional reasons why (Ex.
30-240, p. 367).
Some rulemaking participants (see, e.g., Ex. 30-3686; 31-353)
stated that medical records related to employee exposure to ergonomic
risk factors should be kept for the duration of employment plus 30
years, as OSHA requires for other records covered by 29 CFR 1910.1020,
OSHA's access to employee exposure and medical records standard, while
another commenter (Ex. 30-525) stated that all of the records required
by the standard should be kept according to the requirements of 29 CFR
1910.1020. Another commenter, the National Telecommunications Safety
Panel (Ex. 30-3745, p. 16), expressed concern that the proposed
recordkeeping requirements could potentially conflict with those of 29
CFR 1910.1020 and might raise employee privacy issues because some of
the records could be ``[p]ersonal and individual in nature (e.g. job
hazard analyses to accommodate individual injury or illness)'' and
``[p]rivacy issues beyond mere compliance with [proposed] 1910.940.''
Many commenters (see, e.g., Exs. 30-2116, 2809, 2825, 2847; 3001,
3033, 3034, 3035, 3258, 3259, 3332, 4159, 4534, 4536, 4546, 4547, 4548,
4549, 4562, 4627, 4776, 4800, 4801) maintained that all records other
than MSD management records should be kept for 10 years. Representative
of these comments, Gladys Vereesi argued that a 10 year retention
period would allow an ergonomics program to improve upon past history,
that a 3-year retention period limited the inputs for ergonomics
program evaluation and that ``[i]mportant lessons learned will be lost
(Ex. 30-2116, p. 9).
Access to the records kept. Many rulemaking participants (see,
e.g., Exs. 30-2809, 3001, 2116, 2825, 2847, 3033, 3034, 3035, 3258,
3332, 4159, 4536, 4546, 4547, 4548, 4562, 4627, 4776, 4800; Exs. 32-
339-1, 185-3; Ex. 500-218; Tr. 3488) stated that the final rule should
explicitly provide for access by employees or their designated
representatives to all records required by the standard. Typical of the
views of these commenters is the comment of the United Automobile
Workers (Ex. 32-185-3-1, p. 7), which stated:
Other matters discussed in this section * * * are employee
reports and responses, and control records. First, it should be
clear that these are available to affected employees and their
representatives.
Electronic records. The American Trucking Associations, Inc. (Ex.
30-3330) asked OSHA to add the phrase ``in paper, photographic,
microfilm, microfiche, CD-ROM, electronic or other appropriate format''
to allow employers to ``[t]ake advantage of less costly records storage
alternatives while ensuring retention of the required records * * *''
Responses to comments received. In this section, OSHA specifically
responds to the issues raised by commenters on the proposed
recordkeeping provisions.
First, some commenters (see, e.g., Exs. 30-297, 30-3913, 32-85-3,
32-339-1, Tr. 3488) argued that the ergonomics standard should not have
separate recordkeeping provisions but instead that the Agency's
recording and reporting rule (the ``recordkeeping rule'') (29 CFR Part
1904) should govern such requirements. These commenters are confused
about the purpose of that rule, which is to record all occupational
injuries and illnesses that meet the rule's recordability criteria.
Part 1904 does not address the records necessary for an effective
safety and health program or the records that must be kept by employers
to comply with the Agency's substance-specific or hazard-specific
rules, such as this ergonomics program rule. It is routine and
appropriate for rules addressing specific hazards, such as the confined
spaces rule (29 CFR 1910.146), the lockout/tagout rule (29 CFR
1910.147), and many others, to include recordkeeping requirements
geared to those hazards. Accordingly, OSHA has not adopted this
suggestion.
Many commenters (see, e.g., Ex. 30-2428, Tr. 9207, Ex. 32-21-1-2)
argued that the rule's recordkeeping requirements are unnecessarily
burdensome. OSHA disagrees. Employers must keep records of their
program activities for a variety of reasons: to ensure that the program
is
[[Page 68423]]
working as intended and that resources are not being wasted; to ensure
that MSDs are being addressed effectively, that employees are reporting
their signs and symptoms as early as possible, and that Quick Fix and
other controls are working; and to ensure that MSD management is
helping injured employees to recover as soon as possible. OSHA believes
that the records required by the final rule are the minimum necessary
for an effective program. Simply relying on 200 Logs, medical records,
and evaluation records, as the Edison Electric Institute suggested (Ex.
32-300-1) would mean that an employer would not have records of the
controls implemented, the kinds of MSD signs and symptoms occurring, or
the methods used to conduct job hazard analysis at the establishment.
In this respect, OSHA agrees with the views of one commenter (Tr. 7420)
who noted that there is often a discrepancy between the data on an
establishment's 200 Log and what is happening on the floor: ``When you
actually review the first report of injury, you will conclude that the
OSHA 200 Log * * * has no report of cumulative trauma and/or repetitive
strain injury when in fact musculoskeletal disorders are at epidemic
proportions.'' OSHA believes that most employers would agree that all
of the records required by the final rule will provide information
essential to effective ergonomics programs.
As to the suggestion (see, e.g., Exs. 30-297, 30-3913, 32-185-3-1)
that the retention period be 5 years instead of 3 years to coincide
with OSHA's retention periods under the recordkeeping rule, OSHA notes
that the 3-year retention period specified in the final rule is
consistent with the frequency of required program evaluations, where
these records will be most useful. However, employers are always free
to keep their records for longer retention periods if doing so is
consistent with or beneficial to their management practices. Also, even
where an employer is permitted under paragraph (y) of the final rule to
discontinue the ergonomics program for a job, the employer must still
keep the records required to be kept under paragraph (v) for the amount
of time listed in paragraph (v)(4).
OSHA agrees that employers may keep these records electronically,
and paragraph (v)(1) of the final rule makes this clear.
Some commenters (see, e.g., Exs. 30-1294, 30-3356) urged OSHA not
to require that records of temporary work removals or work restrictions
be kept if such removals or restrictions were ``preventive'' or
``voluntary'' in nature. OSHA is unclear about what the commenters
meant by ``voluntary'' or ``preventive'' restrictions. If the
restriction is assigned after the employee reports signs or symptoms,
the employee has experienced an MSD incident, and removal or
restriction must be treated in accordance with the requirements in
paragraph (v)(1). The restriction or removal of a symptomatic employee
is thus simply a temporary work removal or restriction, as those terms
are used in the final rule. If, on the other hand, the employer assigns
an employee to another job before that employee is symptomatic, the
reassignment is simply an administrative control, i.e., job rotation.
Records of work restrictions or removals are required to be kept by the
final rule; records of routine job reassignments or rotations (i.e.,
those not done as part of the employer's strategy to control or
eliminate MSD hazards) are not.
OSHA agrees with those commenters (see, e.g., Exs. 30-2809, 32-339-
1, 32-185-3, 500-218) who pointed out that the proposal failed to
provide access to records by affected employees and their designated
representatives. The final rule, at paragraph (v)(2) and (v)(3),
corrects this oversight.
Summary. After a review of the rulemaking record, OSHA has decided
in the final rule to retain the proposed 3-year (or until replaced by
an updated record) retention periods for most of the required program
records. The record, as discussed above, contains a wide range of
opinion about the appropriate retention period for these records. OSHA
was not convinced to change the required retention periods either by
comments in favor of very short retention periods (see, e.g., Ex. 30-
3765, which recommends a 90-day comment period) or those arguing for a
retention period of 30 years or more (see, e.g., Ex. 30-525).
Records of job hazard analyses, hazard controls implemented, Quick
Fix controls put in place, ergonomics program evaluations, and MSD
management records must be kept for the employees and jobs covered by
the employer's program. Further, as required by paragraph (v)(2),
employees or their designated representative(s) must be given access to
those records that address their report(s) of MSD incidents and the
employer's response(s) to those reports.
Paragraph (w)--When Does This Standard Become Effective?
In paragraph (w) of the final rule, which corresponds to
Sec. 1910.941 of the proposal, OSHA establishes the date when the final
rule becomes effective. The effective date is the date from which the
compliance deadlines in this section are counted.
In the proposal, OSHA stated that the ergonomics standard would
become effective 60 days after the publication date of the final rule.
OSHA stated that this period would provide sufficient time for
employers to review the final rule, get assistance, and prepare to meet
the initial requirements of the standard as it applied to them.
The proposed effective date section elicited few comments. Some
rulemaking participants (see, e.g., Exs. 30-3686, 32-85-3, Tr. 13132)
agreed with the 60-day effective date. Other commenters (see, e.g.,
Exs. 30-74, 30-3765) felt that 60 days was insufficient. For example,
the Dow Chemical Company (Ex. 30-3765, p. 118) urged OSHA to change the
effective date to 180 days so that companies with existing programs,
like Dow, would have sufficient time to review and make any necessary
changes prior to the standard becoming effective.
OSHA understands that employers with existing programs will need
time to review their programs, either to establish that they qualify
for ``grandfather'' status under paragraph (c) or to modify their
programs to match the requirements of the final rule. However, OSHA
believes that the 60-day date before the final rule takes effect,
together with the additional time allowed for the implementation of the
ergonomics program elements, will allow sufficient time for this
purpose. Moreover, any further delay would unnecessarily deprive
employees of needed protections against MSDs.
George Nagle, the Corporate Senior Director of Environmental Health
and Safety for the Bristol-Myers Squibb Company (Ex. 31-302, p. 1, Tr.
10519-10521) suggested that a pilot program of at least one year should
be implemented in OSHA's national and regional offices prior to
attempting to impose a final ergonomics rule on the regulated
community. However, there was insufficient detail in the suggestion to
determine how such a program would work, or whether such a pilot
program strategy would be beneficial to employees. In addition, there
was little or no support in the record for the implementation of such a
pilot program. OSHA believes that a significant number of companies
have successfully implemented an ergonomics program already; the
economic analysis estimates that approximately 20 percent of general
industry companies have done so. Although it does not believe a pilot
program is necessary, OSHA does intend to provide extensive compliance
[[Page 68424]]
outreach to industry when the standard is published, and has included
useful compliance information in the Appendices to this rule. After
reviewing the record on this issue, OSHA has concluded that the 60-day
effective date is appropriate and sufficient for employers to read and
understand their obligations under this final rule.
Compliance Time Frames
OSHA's approach to compliance deadlines in the proposal differed
from that in other OSHA standards. First, OSHA proposed a long start-up
period so that employers would have time to get assistance before the
compliance deadline. Second, even after the compliance deadlines, OSHA
proposed to give employers newly covered by the standard (e.g.,
employers whose employees develop MSDs after the compliance deadlines
have expired) additional time to set up an ergonomics program and
implement controls. Third, OSHA proposed to allow employers to
discontinue large portions of their ergonomics programs if no MSDs were
reported for a specified period of time.
Paragraph (x)--When Must I Comply With the Provisions of the Standard?
In paragraph (x) of the final rule, which corresponds to proposed
Sec. 1910.942, OSHA establishes deadlines for compliance with the
requirements of the ergonomics standard.
In the proposed rule, OSHA allowed for start-up times for employers
to set up the ergonomics program and implement controls in problem
jobs. The proposal would have required the employer to implement MSD
management promptly when an MSD was reported; to set up management
leadership, employee participation, and hazard information and
reporting within 1 year of the effective date of the final rule; to
implement job hazard analysis, interim controls, and training within 2
years of the effective date of the final rule; and to implement
permanent controls and conduct program evaluation within 3 years of the
effective date of the final rule. The proposed start-up times thus
ranged from 1 to 3 years.
Based on an evaluation of the comments received on the proposed
compliance dates, OSHA has revised them in the final rule. The
compliance deadlines in the final rule are staggered, as they were in
the proposal, although some dates fall earlier and some later than they
did in the proposal. Comments received on the proposed dates, and
OSHA's response to the comments, are discussed below.
Like the proposal, the final rule recognizes that employers need to
begin setting up their ergonomics program soon after the rule is issued
so that they will have an effective process in place in time to meet
the compliance deadlines. Without phased-in start-up periods, some
employers might wait until the last minute to take action. The final
rule's phased-in compliance periods are also designed to ensure that
employees who report MSD signs and symptoms are provided with prompt
intervention (both MSD management and work restrictions) in order to
help resolve the problem quickly and without permanent damage to the
employee. The phase-in approach taken by the Agency was supported by
commenters, such as the AFL-CIO, which stated that ``the overall
timeframes for compliance * * * are more than sufficient'' (Tr. 3488).
Finally, the longer start-up periods will also allow employers to
integrate needed job modifications into their regular production
schedules or processes. The best way to control MSD hazards is often in
the design process; allowing additional compliance time allows
establishments of all sizes to make needed changes to their processes
as part of regular production changes, and perhaps to make those
changes at less cost. The final rule allows an initial period of 4
years for employers to implement permanent controls.
The proposal envisioned two levels of ergonomics programs: a basic
program for manual handling and manufacturing jobs (which included
management leadership, employee involvement, hazard information, and
employee reporting of MSD signs and symptoms) and a full program for
employers whose employees developed work-related MSDs that were covered
by the standard. The full program would have included all of the
elements of the basic program plus job hazard analysis, job controls,
training, and program evaluation. Employers who had manufacturing or
manual handling jobs in their establishments would have had one year
from the effective date of the rule to comply with the basic program
requirements, and later compliance deadlines for other requirements of
the full program (job hazard analysis, job controls, training, and
program evaluation, if a covered MSD is reported).
OSHA has simplified the scope of the final rule by eliminating the
distinction between manual handling and manufacturing jobs and other
jobs. Accordingly, the phased-in compliance deadlines for manual
handling and manufacturing jobs found in the proposal do not appear in
the final rule (see the summary and explanation for paragraph (b)).
Like the proposal, the final rule does not contain different
compliance deadlines for small and large employers. This is the case
because OSHA believes that the compliance deadlines allow enough time
even for very small employers to obtain information about the rule and
ways to implement an ergonomics program. OSHA also believes that the
final rule's 4-year phased-in compliance period for controls is
adequate for larger employers who might have more complex processes,
employees, problem jobs, and controls to implement.
Some rulemaking participants (see, e.g., Exs. 30-3813, 30-3826)
stated that the compliance dates in the proposal were logically
inconsistent and needed to be rewritten. These commenters found this
section on phased-in dates for program requirements to be difficult to
follow and confusing.
Some commenters (see, e.g., Exs. 32-339-1, 182-1, Tr. 383-384)
noted that under the compliance deadlines set forth in the proposal,
some employees with MSDs who had already been removed from their job
might be returned to the problem job before the proposal required the
employer to implement interim controls. OSHA agrees that this could be
the case in some circumstances and has revised the final rule
accordingly.
The compliance time frames in the final rule have been modified as
follows: paragraph (x)(1) gives the employer 9 months after the
standard becomes effective (60 days after promulgation) to provide the
information required in paragraph (d) to employees. This includes
information about MSDs and their signs and symptoms and how to report
MSDs as well as the kinds of risk factors, jobs and work activities
associated with MSDs (see preamble discussion for paragraph (d) for a
more complete discussion of the information required to be
disseminated).
The rest of the compliance time frames are presented in paragraph
(x)(2), Table 2. After an employee reports an MSD (or signs or symptoms
of an MSD), the employer must determine whether the MSD is work
related, whether it requires a work restriction and, where appropriate,
whether the employee's job meets the standard's Action Trigger (see the
preamble discussions for paragraphs (e) and (f) for further details on
these requirements). If an employer determines that an MSD incident has
occurred (i.e., a work-related MSD that requires medical treatment
beyond first
[[Page 68425]]
aid or restricted work, or MSD signs or symptoms that last for 7
consecutive days) (see definition of MSD incident), then the employer
has 7 days in which to determine whether the employee's job meets the
Action Trigger (defined in paragraph (f) of the standard). If the
employee's job meets the Action Trigger, then the employer has 7 days
in which to initiate MSD management, which includes access to a Health
Care Professional (HCP), an evaluation of the employee's condition, any
appropriate work restrictions (including WRP for up to 90 days) (see
preamble discussion of paragraphs (p), (q), (r), and (s) for further
details of the employer's MSD management responsibilities). If the
employee's job meets the Action Trigger, the employer has 30 days in
which to initiate the management leadership element of the program
(assign responsibility for setting up and managing the ergonomics
program and communicating with employees about the ergonomics program)
and the employee participation element (ensuring that employees have
ways to report and receive prompt responses to reported MSDs and have
ways in which to be involved in the development and implementation of
the ergonomics program) (see preamble discussions for paragraphs (h)
and (i) for further details of these requirements).
Within 45 days of determining that a job meets the Action Trigger,
the employer must train employees in setting up and managing the
ergonomics program (see preamble discussion for paragraph (t) for
further details of this requirement). Also, a job hazard analysis of
the problem job must be initiated within 60 days of a determination
that the job meets the Action Trigger (see preamble discussion of
paragraph (j) for further details of this requirement). Within 90 days
after a determination that a job meets the Action Trigger, the employer
must implement interim controls and initiate training for employees,
supervisors and team leaders involved in the ergonomics program (see
preamble discussion of paragraphs (t) and (m)(2) for further details on
these requirements).
Finally, the employer must implement permanent hazard controls to
fix a problem job (so that any MSD hazards presented by the job no
longer are likely to cause MSDs that result in work restrictions or
medical treatment beyond first aid) within 2 years of a determination
that a particular job meets the Action Trigger. The final rule allows
the employer up to 4 years (after a determination that a job meets the
Action Trigger) for initial implementation of the permanent controls
provisions (see preamble discussion of paragraph (m)(3) for further
details of this requirement). The final standard has kept the proposed
requirement to evaluate the effectiveness of the ergonomics program
within 3 years (after a determination that a job meets the Action
Trigger) and to promptly correct any deficiencies in the program that
the evaluation reveals (see preamble discussion of paragraph (u) for
further details of this requirement).
Therefore, the effective date section in the final rule has been
modified to avoid the unwanted results some commenters (see, e.g., Exs.
30-3813, 30-3826) pointed out might have occurred under the proposal's
compliance dates. For example, these commenters noted that, an employee
with a work-related MSD could, under the proposal, be returned to a
problem job before the employer was required to implement interim
controls for that job. In the final rule, the employer has a longer
period than in the proposal--up to 9 months from the effective date of
the rule--to disseminate information to employees about MSDs. After
that date the employer must respond promptly to any reported MSDs by
taking steps to determine if the employee has suffered an MSD incident
(a determination that the MSD is work-related, is persistent, and
requires medical treatment beyond first aid, days away from work or
restricted work). Once it is determined that an MSD incident has
occurred, the employer has 7 days to determine if the employee's job
meets the Action Trigger. If the job meets the Action Trigger, all of
the other requirements of the standard spring from the date of the
Action Trigger determination, and interim controls would need to be
implemented within 90 days of this determination. Therefore under the
final rule, an employee on work restriction or WRP would not have to
face the possibility of returning to an ``unfixed'' job because the WRP
period has expired before the employer has a duty to implement at least
interim controls.
Some rulemaking participants (see, e.g., Ex. 32-339-1, Tr. 3488-
3489) observed that the compliance deadline for management leadership
and employee participation in the proposal fell due before the deadline
for training. Commenters (see, e.g., Ex. 500-218) were concerned that
this phase-in discrepancy would mean that employees would not be able
to fully participate in the ergonomics program because they had not had
training. Although the proposal would not have prevented employers from
training employees prior to the 2-year deadline articulated in the
proposal, OSHA has modified the deadlines for the training requirements
in the final rule to address this concern. The final rule separates the
employer's training obligations into segments (with the awareness
training required by paragraph (d) given earlier than the training
triggered by the Action Trigger). As noted, the final rule includes
some employee awareness training for all general industry employees;
the requirement to provide this training is the first requirement of
the standard to go into effect after the effective date. In addition,
paragraph (h), management leadership, and paragraph (i), employee
participation, have training components (e.g., information on MSDs,
information on the ergonomics program and the requirement to provide
responsible persons with the information and resources necessary to
meet their responsibility under the program).
Some rulemaking participants (see, e.g., Exs. 30-3813, 30-3826)
complained that the terms ``permanent'' and ``interim'' controls used
in the effective date section were undefined. Definitions of
``interim'' and ``permanent'' controls have been included in the final
rule to further clarify the compliance obligations set forth in the
effective date section (see paragraphs (k)(1)(i) and (m)(2)).
A number of commenters (see, e.g., Exs. 30-3745, 30-3913, Tr. 7745-
7746, Tr. 16471) felt that the time periods for compliance given in the
proposal were inadequate. For example, the National Telecommunications
Safety Panel (Ex. 30-3745, pp. 16-17) stated:
Based on previous discussions of individual program elements
within the proposed rule, the Panel believes it would be necessary
for employers with more than 10 worksites and 2500 employees across
those multiple worksites to have two years after a rule becomes
effective to implement ``management leadership'' and ``hazard
information and reporting'' as defined in the rule, three years to
implement ``job hazard analysis,'' ``interim controls,'' and
training, and four years for ``permanent controls'' and ``program
evaluation.'' This reflects the distinct probability that most
telecommunications companies will maintain a corporate ergonomics
program to ensure consistency of compliance, adequate communications
and sharing of ``best practices'' across all of their workplaces.
The National Council of Agricultural Employers (Ex. 30-3781)
indicated that small employers needed a longer phase-in period, which
would allow them to take advantage of innovations undertaken by larger
companies. However, this commenter neither stated what length of time
would be appropriate for small employers nor
[[Page 68426]]
whether more time was needed to comply with all of the provisions of
the standard or just the interim and permanent control provisions. OSHA
also notes that agricultural employment is not covered by this rule
(see the summary and explanation for paragraph (b)). OSHA concludes
that the times given to comply with the program elements in the final
rule are adequate for all employers, including small employers, who
will be able to avail themselves of all of the compliance assistance
materials OSHA is disseminating, the OSHA consultation program, and
other ergonomic resources available.
A number of other comments were received in response to the
compliance date section of the proposal. One rulemaking participant
(Ex. 30-3913) argued that training should be phased-in over 5 years
rather than the proposed 3 years because at present commercially
available ergonomic training materials are of inadequate quality and
more time would be needed to improve the overall quality of such
training materials. OSHA concludes that a wealth of material is already
available that can assist in meeting the training obligations in the
final rule. (See Docket 777, e.g., ``Ergonomics Awareness Manual (Ex.
32-185-3-11);'' ``Trainer's Manual Ergonomics Program (32-111-1-21).'')
In addition even more training materials will become available through
OSHA outreach as well as the market for such materials which the
promulgation of this rule will create. Further, the training
obligations in the final rule are implemented over time, and the
materials for them can thus be developed and implemented piecemeal as
program development occurs within the workplace.
Some participants (see, e.g., Exs. 30-3922, 30-3032, 30-3284, 30-
3922, 32-133-1, 32-300-1, L30-5088, 601-x-1711) thought that the
deadlines for interim or permanent controls were too short. Others
(see, e.g., Exs. 30-526, 30-710, 30-2433) felt that any deadline for
implementing permanent controls was unrealistic, due to the difficulty
of providing permanent controls. For example, Pinnacle West Capital
Corporation (Ex. 30-3032, p. 12) stated:
* * * due to the heavy regulation of the plant modification process
by the Nuclear Regulatory Commission in electric utility nuclear
plants, it is entirely possible that some engineering control
implementation could take more than the [proposed] three year
permanent control deadline. This is particularly true if the
modification can only be accomplished during plant outage times.
This commenter did not indicate how often such plants are off line;
however, OSHA notes that the inability of an employer to comply for
reasons of infeasibility can always be raised in the context of
enforcement. The fact that an employer may confront a highly unusual
situation, such as the one this commenter describes, is no reason for
the implementation dates for all employers to be extended. Another
participant stated that the brick-making industry would have problems
meeting the proposed three-year phase-in period for permanent controls
(Tr. 7745-7746) because they believe that the only permanent controls
for their ergonomics problems is automation. OSHA notes that this
commenter reported making substantial progress in reducing its MSD
hazards, but recognizes that feasibility may be an issue for some
establishments.
The American Industrial Hygiene Association (AIHA) (Tr. 16471)
noted difficulties that might be encountered in meeting the proposed
compliance deadlines for the implementation of interim or permanent
controls by stating that ``[i]n some cases, substantial reductions in
hazards may require reworking an entire material handling system for
even a production line. These types of changes usually require a stage
process that may run over three years.'' Again OSHA understands that
controls can take some time to implement in certain complex cases, and
further that many companies prioritize their jobs for control. OSHA's
compliance staff is trained to address these issues on a case-by-case
basis, and will do so in enforcing this standard as well.
OSHA has determined that, except in rare cases, employers will be
able to meet the compliance deadlines in the final rule. These
deadlines are based on a review of the record on the appropriateness of
the proposed time given to implement permanent controls. As a result of
that review, OSHA has increased the amount of time employers are
allowed to implement permanent controls initially to 4 years after the
final rule goes into effect, and to 2 years thereafter. This means that
the 4-year period is the maximum time that any employer can take to
implement permanent controls. In other words, the employer has 4 years
after the effective date to install permanent controls or 2 years after
the employer determines that a job meets the Action Trigger, whichever
is later. For example, if an employer determines that a job meets the
Action Trigger 1 year after the effective date, that employer will then
have 3 years to install permanent controls. On the other hand, if the
employer makes the Action Trigger determination 3 years after the
effective date (or 4 years or 5 years after), that employer has 2 years
from that date to install permanent controls. This two-tiered approach
to the requirement to implement permanent controls initially was
adopted to allow employers sufficient time to deal with a possible
increase in the number of MSD incidents soon after the standard becomes
effective. The Agency believes, once the standard has been in effect
for several years, there will be fewer MSD incidents, and that a
shorter compliance deadline for permanent controls--2 years--will give
these employers sufficient time to implement permanent controls for
problem jobs.
The few employers who may find the generous compliance times given
in the final rule inadequate also may avail themselves of the temporary
variance procedures provided in the Occupational Safety and Health Act
of 1970.
Many commenters felt that the compliance deadlines were too long
(see, e.g., Exs. 30-2039, 30-2116, 30-2825, 30-2847, 30-3001, 30-3033,
30-3034, 30-3035, 30-3258, 30-3259, 30-30-3332, 30-3686, 30-4159, 30-
4534, 30-4536, 30-4546, 30-4547, 30-4548, 30-4549, 30-4562, 30-4627,
30-4776, 30-4800, 30-4801, 31-242, 31-353, 32-85-3, Tr. 11196, 13133).
Typical of comments stating that the deadlines were too long was
that of the American Nurses Association (ANA) (Ex. 30-3686, p. 22),
which criticized the deadlines on the grounds that they were so long
that they would continue to permit opportunities for thousands of
nurses and HCWs (health care workers) to be injured. Although the
immediate implementation of effective controls on jobs with MSD hazards
would be ideal, OSHA recognizes that employers will need time to find,
implement, and analyze the effectiveness of controls for each job. OSHA
has modified the compliance time frames to address comments such as the
ANA's by significantly shortening the amount of time allowed in the
final rule for employers to address jobs that meet the Action Trigger.
In the final rule, for example, interim controls must be implemented
within 90 days of a determination that a job meets the Action Trigger,
as opposed to the 2 years given in the proposal. Further, the deadlines
in the final rule represent the maximum amount of time employers will
have to comply with the elements of the ergonomics program. Employers
are encouraged to implement effective controls as soon as possible, and
OSHA believes that many employers will do so, because this approach
will benefit both employers and employees by
[[Page 68427]]
reducing the number and gravity of MSD injuries.
Other commenters supported the proposed time frames. For example,
the AFL-CIO (Tr. 3488) stated ``[t]he overall time frames for
compliance we think are more than sufficient, particularly given that
the standard has been under development for so long.'' OSHA understands
that the compliance deadlines given are generous, but has concluded
that some companies will need the extra time to work needed job
modifications into their regular production change schedules. From a
review of the comments on this section, OSHA has determined that the
final rule strikes a rational balance between the need to respond with
due speed to MSD incidents and the benefits of developing remedies to
problem jobs in an orderly fashion. Substantial evidence in the record
supports the compliance time frames adopted in the final rule.
The Communications Workers of America (CWA) (Tr. 13133) supported
the requirement for prompt responses to reported MSDs, but felt that
the remaining requirements (management leadership and employee
participation, hazard information and reporting, job hazard analysis,
training, interim and permanent controls, and program evaluation)
should all begin one year after the effective date of the standard. The
CWA (Tr. 13133) also stated that hazard information training should be
conducted within 30 days after the identification of a problem job. In
the final rule, this initial training is required before the
identification of a problem job. The CWA also suggested that
comprehensive training on MSD hazards, controls, and the employer's
ergonomics program should be required 90 days after the identification
of a problem job. As noted above, in the final rule, all of the
training requirements go into effect within 90 days of a determination
that a job meets the Action Trigger. Several training requirements,
such as the dissemination of MSD awareness information to employees
(paragraph (d)) and the training of employees involved in setting up
the ergonomics program (paragraph (t)) have to be met substantially
sooner.
Some commenters agreed that MSD management should be provided
immediately, or as soon as possible (see, e.g., Exs. 30-2387, 30-4538,
31-105, 31-106, 31-129, 31-170, 31-229, 31-276, 31-309, Tr. 13133).
Other participants (see, e.g., Exs. 30-74, 30-2987) felt that the
requirement for prompt response, i.e., as soon as an MSD is reported
after the effective date, could be disruptive and would result in an
employer having insufficient time to prepare for the implementation of
the overall ergonomic program requirements. The American Health Care
Association (AHCA) (Ex. 30-2987) recommended at least a 1-year delayed
effective date for MSD management. The AHCA stated ``[b]ecause we
anticipate that MSDs will be reported early under this proposed
standard, we envision that the MSD management component deadline will
occur almost immediately after the 60-day start-up. This hardly
provides an opportunity for employers to receive assistance on MSD
management * * * '' In the final rule, the dates in the proposal have
been modified to clarify that, although the employer has 11 months from
the time the standard is published to disseminate information about
MSDs (including their signs and symptoms and how to report them), the
employer need not respond to the employee reports initially until the
11-month period has passed. This initial delay in employer response
obligations is necessary to permit the employer to develop an ergonomic
program in an orderly fashion.
Some commenters felt that after the standard became effective
employers should be given 5 days to respond to MSD reports (see, e.g.,
Exs. 30-400, 30-4837, 31-3, 31-12, 31-113, 31-31-150, 31-160, 31-186,
31-187, 31-192, 31-200, 31-205, 31-243, 31-307, 31-347); others thought
that 2 days would be appropriate (Ex. 31-23). These commenters only
provided their opinions in this matter, without detail. Other periods
of time were also recommended for MSD management deadlines, such as 1
month (Exs. 31-125, 31-265 ), again without detailed explanation. The
proposal (Sec. 1910.942) had merely required that the employer provide
a ``prompt'' response. This requirement has remained essentially the
same in the final rule but has been included in paragraph (e) rather
than in the effective date section (see preamble discussion of
paragraph (e) for a more detailed discussion of the MSD response
requirements).
Some commenters (see, e.g., Exs. 31-27, 31-78, 31-170, 31-180)
argued that medical treatment deadlines for MSDs are addressed in state
workers' compensation laws and that OSHA should not interfere with
those requirements. These commenters misunderstand the rule's MSD
management provisions. The OSHA rule does not require employers to
obtain medical treatment for employees with MSDs; OSHA assumes that
MSDs will continue to be treated under the workers' compensation
system, as they have been. The MSD management required by the standard
requires the employer to provide access to an HCP, if the employee
wishes access, solely for the purposes of evaluation and follow-up and,
if necessary, work restrictions. The MSD management system required by
the standard does not in any way interfere with workers' compensation
(see preamble discussion of paragraph (q)). OSHA included the MSD
management provisions pursuant to its statutory authority under the OSH
Act (see preamble discussion of paragraph (r)). After reviewing a wide
variety of opinions as to how long injured employees should wait before
receiving MSD management, OSHA has concluded that MSD management should
begin within 7 days after a determination can be made that an MSD
incident, as defined by this standard, has occurred. Compliance dates
are necessary to effectuate the MSD management provisions included in
the standard, and OSHA believes that the time frames included in the
final rule for MSD management are appropriate and supported by the
record.
In Sec. 1910.943, OSHA proposed to establish different compliance
time frames for those employers who had not identified a problem job
until after some or all of the start-up compliance deadlines
established in proposed Sec. 1910.942 had passed. This was because the
occurrence of an MSD incident is difficult to predict and may not
occur, in some establishments, for many years, i.e., long after the
standard's initial start-up dates have run.
In proposed Sec. 1910.943, if an employer incurred a compliance
obligation after the compliance start-up deadline for that obligation
had passed, a different timetable applied. OSHA's reasons for this
timetable, which was shorter than the initial compliance timetable, was
that employers in later years would not need as long to implement
ergonomics programs because they could take advantage of program
development and remedies that had been developed by other employers in
the interim. Accordingly, proposed Sec. 1910.943 gave employers with
later incurred compliance obligations some additional time to comply,
but the time frame between the MSD incident and the remedy was shorter
than that proposed for initial compliance when the standard became
effective (see 64 FR at 66074).
From a review of the rulemaking record, it is clear that many
participants did not understand proposed Sec. 1910.943 or how it would
work (see, e.g., Exs. 30-2116, 30-2809, 30-2825, 30-2847, 30-
[[Page 68428]]
3001, 30-3033, 30-3034, 30-3035, 30-3258, 30-3259, 30-3332, 30-3826,
30-4159, 30-4534, 30-4536, 30-4546, 30-4547, 30-4548, 30-4549, 30-4562,
30-4627, 30-4776, 30-4800, 30-4801, Tr. 3236). Additionally, this
section of the proposed rule elicited a number of comments, most of
which were critical (see, e.g., Exs. 32-85-3, 30-297, 30-424, 30-434,
30-1090, 30-2433, 30-3120, 30-3171, 30-4537, 32-85-3, 500-145).
However, few commenters provided detailed reasons for their views.
A few commenters (see, e.g., Exs. 30-4538, 30-3686, 31-353, 32-300-
1) recommended that proposed Sec. 1910.943's requirement that MSDs be
responded to within 5 days be modified to require MSD management
``promptly'' when an MSD is reported. The American Federation of
Government Employees (Ex. 30-4538, p. 8) stated:
OSHA should require medical management sooner than five days. If
an employee experiencing MSD symptoms continues to work in the same
job without medical attention, his condition could get worse. In
general, by the time an employee reports a problem, she has been
experiencing symptoms for some time and should not have to wait
another few days for treatment.
Some rulemaking participants (see, e.g., Exs. 30-240, 30-526, 30-
710, 30-3813, 30-3826, 30-3284, 32-300-1, 501-6) disagreed with the
idea of providing less time for later-year compliance in Sec. 1910.943
than was proposed for initial compliance in Sec. 1910.942. For example,
the Department of Defense (Ex. 30-3826, p. 11) stated ``[i]t is not
clear why two timetables are provided. It seems capricious to allow
some employers up to three years to fully implement their ergonomics
programs, while others will have only one year.''
Another rulemaking participant (Ex. 32-229-1) observed that the
proposed deadline for training expires after the deadline for
management leadership and employee participation, which would mean that
employees would not be trained before they are expected to participate.
In response, OSHA has shortened the deadline for training for employees
who are involved in setting up and managing the ergonomics program in
the final rule from the proposed 90 days to 45 days after the employer
has determined that a job meets the Action Trigger. Employee
participation has a deadline of 30 days after the employer has
determined that the job meets the Action Trigger.
As noted earlier, in the final rule, the events that trigger an
employer's obligations under this standard have been modified since the
proposal. All employers covered by the ergonomics standard must comply
with the minimal requirements in paragraph (d) (informing employees)
within 11 months of the publication of the rule. The remainder of the
rule's obligations and time frames for complying with the various
requirements are incurred after a determination that an MSD incident
has occurred in a job that meets the Action Trigger set forth in
paragraph (f). In view of this altered approach in the final rule, it
is no longer necessary to provide two separate compliance time frames
as was done in the proposal.
Paragraph (y)--When May I Discontinue my Ergonomics Program for a Job?
Paragraph (y) allows employers to discontinue most elements of
their ergonomics program for a job if the risk factors in that job have
been reduced to levels below those in the Basic Screening Tool (Table 1
of the standard). The only obligations the employer continues to have
for jobs that have been controlled to that level are to maintain the
controls that reduce the risk factors, continue to provide the training
related to those controls, and keep records of the job hazard analysis
and the controls implemented for that job.
OSHA proposed to allow employers to discontinue portions of their
ergonomics program when no covered MSD had been reported in a problem
job for 3 years after the problem job was controlled. Paragraph (y) of
the final rule has the same advantages as the proposed provision, but
has been revised to reflect changes made to the design of the final
rule. That is, the approach taken in the final rule recognizes the role
of the Basic Screening Tool in Table 1, which acts, along with the
report of an MSD incident, as a trigger for action under the standard
and, in paragraph (y), as the mechanism for relieving employers of most
of their obligations under the standard.
Some rulemaking participants (see, e.g., Exs. 30-526, 30-710, 30-
3686, 31-242) argued that the 3-year timetable for discontinuing
elements of the program should be eliminated. These commenters felt
that employers with ergonomics programs should be required to maintain
all elements of their ergonomics program indefinitely.
Commenters took issue with the proposed timetable for discontinuing
parts of the program; some thought the time period was too short, while
others argued that it was too long. For example, one rulemaking
participant (Ex. 32-185-3) stated that 3 years is too soon to
discontinue parts of the ergonomics program, because it gives
insufficient time for employers to accurately determine if the controls
implemented have been effective. However, this commenter did not
suggest what amount of time would be appropriate to wait before
discontinuing parts of the program.
On the other hand, some rulemaking participants (see, e.g., Exs.
30-3471, 30-4185, 30-3868, Tr. 3325-3326) thought that 3 years was too
long to wait before discontinuing certain aspects of the program. For
example, Tyson's Foods (Ex. 30-4185, p. 26) stated ``* * * OSHA has set
an unrealistically * * * low threshold * * * by premising the
obligation to implement engineering controls on the existence of * * *
a single reported MSD and then further requiring employers to continue
to search for and implement engineering controls until there are no
more MSDs for at least three years * * *''
Other commenters (see, e.g., Exs. 30-3344, 30-3749, 30-4674, Tr.
3325-3326, Ex. 601-x-1710) recommended using alternative criteria for
discontinuing elements of the program. For example, Abbott Laboratories
(Tr. 3325-3326) stated ``clearly the bar for ending the full program is
too high. We propose that OSHA substitute a performance-based
replacement for the `one MSD in three years' criterion.'' OSHA has
considered this suggestion but has determined that such a performance-
based approach, such as the use of industry averages, would be too
complex to apply and too difficult to verify during enforcement.
Some commenters (see, e.g., Exs. 30-2116, 30-2825, 30-2847, 30-
3001, 30-3035, 30-3258, 30-3259, 30-4159, 30-4534, 30-4536, 30-4546,
30-4547, 30-4548, 30-4549, 30-4562, 30-4627, 30-4801, 32-85-3,
Tr.13134) stated that the proposed rule would permit employers to
discontinue too many elements of the ergonomics program. The
Communications Workers of America (Tr.13134), for example, stated that
management leadership and employee participation, hazard information
and reporting, awareness training, program evaluation, and maintenance
of controls and the training related to those controls should be
continued to ensure the control or prevention of MSDs.
OSHA has considered the possibility of increasing the number of
program elements employers are allowed to discontinue if they have
reduced the MSD hazards in jobs covered by the standard to levels below
those in the screen (Basic Screening Tool in Table 1). However, the
Agency has decided that maintaining the controls that allowed the
employer to control the job,
[[Page 68429]]
continuing the training in the use of those controls for employees in
these jobs and keeping records of the job hazard analysis and controls
for that job are the minimum requirements needed to ensure employee
protection. These are the only program requirements the employer is
required to continue once the risk factors in the job have been reduced
to levels below the screen.
Paragraph (y) contains no time period and no link to the occurrence
of MSD incidents, as the proposal did. Instead, both the ``entrance''
to and ``exit'' from most program obligations is tied to the extent of
the risk factors in the job, as indicated by the screen.
Paragraph (z)--Definitions
Paragraph (z) of the final rule contains a number of definitions of
terms used in this final rule. Most of the definitions are
straightforward and self-explanatory. A general discussion of each of
the terms can be found below; however, clarification of many of the
terms is provided in the summary and explanation sections for the
provisions where the terms are used. OSHA believes that describing
terms where they are used makes it easier for employers and employees
to understand what OSHA means when it uses them.
The following terms are defined in the final rule: ``administrative
controls,'' ``Assistant Secretary,'' ``control MSD hazards,''
``Director,'' ``employee representative,'' ``engineering controls,''
``follow-up,'' ``health care professionals (HCPs),'' ``job,''
``musculoskeletal disorder (MSD),'' ``MSD hazard,'' ``MSD incident,''
``MSD signs,'' ``MSD symptoms,'' ``personal protective equipment,''
``problem job,'' ``risk factor,'' ``work related,'' ``work practices,''
``work restriction protection (WRP),'' ``work restrictions,'' and
``you.''
Several terms were defined in the proposal (64 FR 65864 and 64 FR
66075) but are not defined in the final rule: ``covered MSD,''
``eliminate MSD hazards,'' ``ergonomics,'' ``ergonomic design,''
``ergonomic risk factors,'' ``have knowledge,'' ``manual handling
jobs,'' ``manufacturing jobs,'' ``materially reduce MSD hazards,''
``MSD management,'' ``no cost to employees,'' ``OSHA recordable MSD,''
``periodically,'' ``persistent MSD symptoms,'' ``physical work
activities,'' and ``resources.'' These terms are either not being used
in the final rule, have been replaced by other terms that are defined
(either in this paragraph or where they first appear), or have such
clear meanings that further definition is unnecessary.
General Comments on Definitions
OSHA received many comments on the definitions for terms used in
the proposed ergonomics program standard. A great deal of comment
focused on the perceived vagueness of the terms and definitions, with
commenters raising concerns about their inability to understand these
terms and, thus, their ability to comply appropriately. Others raised
concerns about the cost of compliance, arguing that they would spend
large sums of money trying to comply because they were unsure what the
rule meant (see, e.g., Exs. 32-207-1, 32-206-1, 30-3765, 30-3845, 30-
3813, 32-368-1, and 30-3853). One commenter, Monsanto Corporation (Ex.
30-434), recommended moving the definitions to the front of the
document for clarity. OSHA has not adopted this recommended change,
although a Note to paragraph (a) of the rule states that the
definitions for the standard appear in paragraph (z).
OSHA has arranged its discussion of the comments on definitions so
that the ``general'' comments--those that apply to all definitions--are
discussed first, and the more specific comments--those that pertain to
a particular term or definition--are discussed afterward. Additional
discussion of some terms can be found in the summary and explanation of
the provision where the term is used.
On the overall issue of the vagueness of the definitions,
commenters said that terms were unclear or too broadly defined, which
would make it difficult for them to implement the standard (see, e.g.,
Exs. 30-294, 30-434, 30-1897, 30-3765, 30-2208-2, 30-3845, 30-1722, 30-
3813, 30-4185, 30-3739, 30-4006, 30-2705, 30-4038, 601-X-1379, 30-3889,
30-2540, 30-4760, 30-4021, 33-1455, 30-4599, 33-1463, 33-1462, 30-2751,
30-4982, 30-5009, 30-2598, 30-2569, 30-4149, 30-4963, 30-4222, 30-4023,
30-4224, 30-4060, 30-4063, 30-2280, 30-3793, 30-4235, 30-2540), 500-1-
4, 500-1-5, and 500-1-28).
The comments of the National Automobile Dealers Association are
representative of the comments received on the general issue of the
vagueness of the proposed definitions:
To the extent that the ergonomics rule remains inexorably tied
to the reporting of MSD risks, MSD symptoms, MSDs, OSHA recordable
MSDs, and covered MSDs, [automobile] dealers will be forced to
closely scrutinize reported MSD signs and symptoms, to screen out
those that are not tied to real MSDs, and to avoid identifying OSHA
recordable MSDs. To be sure, proposed section 1910.145 lists
somewhat helpful definitions for each of these terms. Nonetheless,
these definitions are lacking in that they fail to provide
sufficient guidance to enable dealers to make practical, cost
effective, and objective determinations (Ex. 4839).
Some commenters were concerned that the terms lacked objective
criteria (see, e.g., Exs. 32-206-1, 30-3765, 30-1722, 30-4185, 30-3826,
30-4538, 32-300-1, 30-3336, 30-2208-1, 30-3853, 30-3749, and 30-3167).
Some commenters suggested that OSHA should use definitions for certain
terms that had been established by outside organizations (see, e.g.,
Exs. 30-3765, 30-4499, and 30-3167). Another commented that there was
no consensus definition on many of the terms; that experts are not in
agreement on the root cause and true definition of MSDs; and that
scientists find it difficult to explain why different individuals
working on the same job will not experience the same symptoms (Ex. 30-
3167). Some of the commenters disagreed with the way the terms were
defined or offered suggested alternatives (see, e.g., Exs. 30-3765, 30-
4185, 30-3826, 30-2208-2, 30-1722, 32-111-4, 30-4538, 30-3934, 32-198-
4, 32-300-1, 30-2208, 30-4499, 30-3818, 30-3000, 31-242, 30-4499, 30-
3867, 30-3818 and 30-434).
The Department of Defense (DoD) (Ex. 30-3826) suggested that OSHA
eliminate the need for many of the definitions, such as those for
manufacturing jobs, manual material handling, and several terms used
within those definitions, by simply including all general industry
employers in the scope of the standard. OSHA notes that the scope of
the final rule has been revised so that it is no longer necessary to
define ``manufacturing jobs'' and ``manual handling jobs.'' (See the
summary and explanation discussion on Scope, paragraph (b).)
Some commenters argued that the definitions' vagueness meant that
OSHA's cost estimates would be substantially underestimated because
employers would do ``everything'' in an attempt to comply (see, e.g.,
Exs. 32-206-1, 32-141-1 and 30-3813). Another commenter questioned
whether the rule would result in a substantial reduction in MSDs
because it was so unclear (Ex. 32-368-1). Others said that if the
standard cannot be understood, it is not legally defensible, citing
cases such as Kent Nowlin Construction Co. v. OSHRC, Connally v.
General Constr. Co., and Diebold Inc. v. Marshall (Exs. 30-1897, 32-
206-1, 32-368-1 and 30-3336).
In response to these comments, OSHA has redefined many terms in the
final rule, deleted others, and provided greater clarity in several
areas that were particularly singled out for comment
[[Page 68430]]
such as the level of control employers must reach. Revised provisions
of the final rule that provide definite compliance endpoints and ``safe
harbors'' for employers are examples of these changes. The issue of
``fair notice'' (vagueness) is discussed in the section of the preamble
entitled ``Other Statutory Issues''. Thus the final rule addresses the
concerns of employers by providing objective criteria and establishing
clear obligations for employers to follow.
Specific Comments on Definitions
Administrative controls are defined as changes in the way that work
in a job is assigned or scheduled that reduce the magnitude, frequency,
or duration of exposure to ergonomic risk factors. Examples of
administrative controls include employee rotation, employer-designated
rest breaks designed to reduce exposure, broadening or varying job
tasks (job enlargement), and employer-authorized changes in work pace.
The definition of the term administrative controls is essentially
unchanged from the proposal. OSHA received one comment on the
definition (Ex. 30-3748), which noted that the proposed definition was
clear.
The term Control MSD hazards means to reduce MSD hazards to the
extent that they are no longer reasonably likely to cause MSDs that
result in work restrictions or medical treatment beyond first aid. This
is a new term in the final rule. OSHA has included a definition for
this term in the final rule because paragraph (k) of the standard
requires employers to control MSD hazards. Controlling hazards means
that the risk factors that were occurring at a magnitude, duration, or
frequency sufficient to cause an MSD hazard have been reduced to the
extent that they are no longer reasonably likely to cause MSDs that
result in work restrictions or medical treatment beyond first aid.
Employers are to use engineering, work practice, or administrative
controls or personal protective equipment to control MSD hazards.
The proposed rule contained two similar terms--``eliminate MSD
hazards'' and ``materially reduce MSD hazards.'' Commenters alleged
that these terms were vague and incapable of quantification (see, e.g.,
Exs. 30-1897, 32-206-1, 32-368-1, 30-3765, 30-1101 and 30-2986).
Statements in the record said that the term ``eliminate MSD hazards''
should not be used because it is not possible to eliminate hazards so
completely that MSDs will no longer occur. There will always be
ergonomic risks, according to these commenters (see, e.g., Ex. 30-
3765). In addition, there were statements that the term ``eliminate MSD
hazards'' is not really different from ``materially reduce MSD
hazards'' (see, e.g., Ex. 32-300-1). Comments on the term ``materially
reduce MSD hazards'' stated that employers would not be able to
evaluate whether or not material reductions in risks have occurred and
expressed concern that the term could be interpreted differently by
employers, employees, and OSHA inspectors (see, e.g., Ex. 30-3845).
Some commenters also objected to some of the phrases used in the
proposal definition of ``materially reduce MSD hazards,'' such as
``magnitude,'' ``likelihood,'' and ``significantly'' (see, e.g., Exs.
30-1897, 30-3765, 30-3866, 32-300-1, 30-4467).
In response to comments in the record, OSHA has decided to delete
the terms ``eliminate MSD hazards'' and ``materially reduce MSD
hazards'' from the final rule. Instead, the Agency has defined
``control MSD hazards'' more clearly and has additionally provided
clear compliance endpoints that essentially cure the vagueness
objections raised.
OSHA also received a comment from the Department of Defense (Ex.
30-3826), which recommended that definitions be developed for
``interim'' and ``permanent controls,'' stating:
The timetable in [proposed] Sec. 1910.943 included reference to
``(e) interim controls'' and ``(g) permanent controls''; however,
there are no corresponding sections nor definitions within section
1910.945 that discusses their distinction. At what point does an
interim control become a permanent control, especially when the
employer is following the incremental abatement process guidance
contained within 1910.922. * * * According to some sources, the only
permanent control for ergonomic hazards is an engineering control--
administrative and work practice controls can almost always be
circumvented in the name of convenience, schedule or production.
Unfortunately, in many cases, there are no feasible engineering
controls for identified ergonomic hazards. Therefore, permanent
controls must be defined, and criteria for determining whether an
employer has fulfilled the requirement must be identified (Ex. 30-
3826).
The final rule does not use the term ``interim'' controls. The terms
used in the standard, ``initial controls'' and ``permanent controls,''
are self-explanatory; they are discussed in the summary and explanation
for paragraph (m).
The term Employee representative means a person or organization
that acts on behalf of an employee. This term was not defined in the
proposal, but is included in the final rule for clarification.
Additional discussion relating to the meaning of this term can be found
in the summary of explanation of paragraph (i).
Engineering controls are defined in the final rule as physical
changes to a job that reduce MSD hazards. Examples of engineering
controls include: changing, modifying, or redesigning workstations,
tools, facilities, equipment, materials, or processes.
The definition of the term ``engineering controls'' has been
changed from the proposal. In the proposal, OSHA defined engineering
controls as physical changes that eliminated or materially reduced the
presence of MSD hazards, a term also defined in the proposal. OSHA
defined the term ``materially reduce MSD hazards'' to mean ``to reduce
the duration, frequency and/or magnitude of exposure to one or more
ergonomic risk factors in a way that is reasonably anticipated to
significantly reduce the likelihood that covered MSDs will occur.''
(See the discussion of these terms above, in the section on ``Control
MSD hazards.'') One commenter stated that the definition of engineering
controls was clear (Ex. 30-3748).
The term Follow-up means the process or protocol an employer or HCP
uses (after a work restriction is imposed) to check on the condition of
employees who have experienced MSD incidents. The definition of the
term ``follow-up'' is essentially the same as the proposed definition,
except that OSHA has removed a sentence from the proposed definition
that explained why ``follow-up'' was necessary. The sentence removed
was ``Prompt follow-up helps to ensure that the MSD is resolving and,
if it is not, that other measures are promptly taken.'' No substantive
comments on this definition were received. Additional discussion
relating to the meaning of this term can be found in the summary and
explanation for paragraph (p).
Health care professionals (HCPs) are physicians or other licensed
health care professionals whose legally permitted scope of practice
(e.g., license, registration or certification) allows them to provide
independently or be delegated the responsibility to provide some or all
of the MSD management requirements of this standard. This definition is
identical to the definition in the proposed rule.
One commenter asked OSHA to clarify the definition to specify which
occupations (physician, nurse, physical therapist, etc.) were included
in the term ``HCP'' (Ex. 30-74). Others were of the opinion that the
definition was too broad (see, e.g., Exs. 30-991, 30-3004, 30-3934, 30-
3937, 30-2208 and 32-22).
[[Page 68431]]
The comments of the Combe Company are representative: ``[b]y allowing
persons who do not even have a medical degree to diagnose and treat
these disorders, the proposed standard creates an environment where the
potential for misdiagnosis and improper treatment efforts is
dramatically increased'' (Ex. 30-3004). In response to these comments,
OSHA notes, first, that the final rule's MSD management section does
not require the diagnosis and treatment of MSDs; these medical aspects
of MSDs are left to the workers' compensation system, as they always
have been. The MSD management envisioned by the standard entails the
evaluation of an MSD to identify the need for work restrictions and
follow-ups to ensure that recovery is progressing. Second, the Agency
is deferring to the states on the issue of permitted scopes of
practice; that is, different states permit different HCPs to perform
different healthcare activities, and employers are expected to
ascertain that the HCPs they rely on to carry out the MSD management
responsibilities under the standard are licensed, registered, or
certified to perform these functions.
Commenters proposed an alternative definition of HCP, i.e., that in
addition to requiring licensing, OSHA require HCPs to have sufficient
training and experience in diagnosing and treating MSD injuries/
illnesses (see, e.g., Exs. 30-3934 and 30-3937). Another organization
pointed out that because the definition is so broad, it could include
occupations such as emergency medical technicians or licensed
vocational nurses who would not be the appropriate professionals to
make decisions with respect to MSDs (Ex. 30-2208). The New Mexico
Workers' Compensation Administration argued that under the proposed
definition, a massage therapist could render an opinion on MSDs (Ex.
32-22). Again, OSHA is confident that the state scope of practice laws
that govern HCPs will ensure that only appropriate personnel are
permitted to carry out the standard's MSD management functions.
Some commenters urged OSHA to limit the term HCP only to physicians
on the grounds that fact finders rely heavily on treating physician's
opinions when litigating causation issues under the various workers'
compensation laws (see, e.g., Exs. 30-3749, 30-3344 and 30-4674).
OSHA's medical management provisions are independent of and unrelated
to the workers' compensation system's procedures for determining
medical treatment, or extent-of -disability determinations (see the
discussion in the summary and explanation for paragraphs (p), (q), (r),
and (s)).
The American College of Occupational and Environmental Medicine
(ACOEM) recommended that the definition of health care professional be
changed to ``occupational physicians or other licensed occupational
health care professionals,'' to focus on the HCP's training and
competencies in occupational medicine. OSHA has not revised the
definition of HCP in this standard, although OSHA believes that many
employers recognize and only rely on the expertise of occupational
physicians and nurses. OSHA's more recent standards (see, e.g., the
Respirator standard and the Methylene Chloride standard) have used the
term HCP, and have defined it in the same way as in this ergonomics
standard; changing it would thus be inconsistent with recent usage. The
other issues raised by ACOEM--such as the kinds of activities
encompassed by the term MSD management--are discussed in the summary
and explanation for that paragraph (paragraph p).
The American Society of Safety Engineers (ASSE) (see, e.g., Ex. 30-
386) asked OSHA to include a definition of ``safety professionals'' in
the rule and to acknowledge the important role of these professionals
in ergonomics programs. The preamble to the final rule does so, and
specifically mentions the role of safety professionals, industrial
hygienists, and other safety and health professionals in ergonomics
program implementation.
The term Job is defined in the final rule to mean the physical work
activities or tasks that an employee performs. For the purpose of this
standard, OSHA considers jobs to be the same if they involve the same
physical work activities or tasks, even if the jobs that require those
activities or tasks have different titles or job classifications. OSHA
is retaining the definition for the term ``job'' unchanged from that in
the proposed rule, except for the addition of the word ``tasks''.
Comments on the definition of ``job'' in the proposal stated that
the definition gave little guidance on how employers were to determine
whether jobs were the same (Ex. 30-3784) and that OSHA should change
the word ``job'' or ``job based'' to ``task'' or ``task based'' (Exs.
30-3765 and 30-3826). The Department of the Navy (Ex. 30-3818) also
recommended that OSHA focus on job tasks rather than the job because
the term ``job'' is frequently associated with titles and position
descriptions. The Department of the Navy also asked OSHA to define the
word ``task'' in the final rule. OSHA believes that the final rule's
definition of a job as the physical activities or tasks that an
employee performs is responsive to the Navy's concerns. For a
discussion of the meaning of tasks in the context of job hazard
analysis, see the summary and explanation for paragraph (j). In
addition, the presence of the Basic Screening Tool will enable
employers to identify jobs that are the same, despite, for example,
differences in job titles.
Musculoskeletal disorders (MSDs) is defined in the final rule as:
a disorder of the muscles, nerves, tendons, ligaments, joints,
cartilage, blood vessels, or spinal discs. For purposes of this
standard, this definition only includes MSDs in the following areas
of the body that have been associated with exposure to risk factors:
neck, shoulder, elbow, forearm, wrist, hand, abdomen (hernia only),
back, knee, ankle, and foot. MSDs may include muscle strains and
tears, ligament sprains, joint and tendon inflammation, pinched
nerves, and spinal disc degeneration. MSDs include such medical
conditions as: low back pain, tension neck syndrome, carpal tunnel
syndrome, rotator cuff syndrome, DeQuervain's syndrome, trigger
finger, tarsal tunnel syndrome, sciatica, epicondylitis, tendinitis,
Raynaud's phenomenon, hand-arm vibration syndrome (HAVS), carpet
layer's knee, and herniated spinal disc. Injuries arising from
slips, trips, falls, motor vehicle accidents, or similar accidents
are not MSDs.
The definition of ``musculoskeletal disorder (MSD)'' in the final
rule differs somewhat from the proposed definition. The final rule
limits the definition to those MSDs involving certain body parts: the
neck, shoulder, elbow, forearm, wrist, hand, abdomen (hernia only),
back, knee, ankle and foot. This definition, and the purpose paragraph
(paragraph (a)) both also make clear that this standard does not cover
injuries caused by slips, trips, falls, motor vehicle accidents, or
other similar accidents (e.g., being caught in moving parts). OSHA has
made these changes in response to criticisms that the proposed
definition was too broad (see, e.g., Ex. 30-1216, 30-2035, 30-3866, 30-
4821, 32-208-1, 32-368-1, 30-3937, 500-1-116, Tr. 15310).
Some commenters raised issues about the MSDs covered by the
standard and their relationship to psychosocial effects and non-
occupational factors (see, e.g., Exs. 500-1-1116, 30-3211, 30-3866).
These comments and issues are discussed in the Health Effects section
of the preamble, Section V, rather than in this definitions section.
Other commenters objected because the acronyms MSD and MSDs are
similar to MSDS, which stands for the Material Safety Data Sheets
required by OSHA's hazard communication standard, 29 CFR 1910.1200
(see, e.g.,
[[Page 68432]]
Exs. 30-2041 and 30-0522). However, because ``musculoskeletal
disorder'' is the scientifically correct term for these conditions and
MSD is the widely known abbreviation for the term, OSHA continues to
use both ``musculoskeletal disorders'' and its acronym in the final
rule.
Some commenters urged OSHA to add other examples such as thoracic
outlet syndrome to the list of examples accompanying the definition
(see, e.g., Exs. 30-2825 and 30-3332). The list of MSDs included in the
final rule is only a list of examples; OSHA recognizes that there are
many other MSDs, such as thoracic outlet syndrome, that could be
included in this list.
There was some comment that OSHA should adopt a definition of MSDs
developed by other organizations such as NIOSH (see, e.g., Exs. 30-3211
and 30-3765). For example, the Dow Chemical Company (Ex. 30-3765)
recommended that OSHA adopt the NIOSH definition of MSD and the Society
for Human Resource Management (Exs. OR-364, Tr. 15310-15311) suggested
that OSHA rely on a medical definition of MSD, such as one taken
directly from Merck's Manual.
OSHA's definition of MSD is, in fact, very similar to NIOSH's
definition, as reflected in the Institute's publication, Elements of
Ergonomics Programs (DHHS, Publication No. 97-117), particularly with
respect to the soft tissues included and the exclusion of accidental
injuries.
MSD hazard means the presence of risk factors in the workplace that
occur at a level of magnitude, duration, or frequency that is
reasonably likely to cause MSDs that result in work restrictions or
medical treatment beyond first aid. The definition of ``MSD hazard'' in
the final rule differs from the definition in the proposed rule; it has
been revised for clarity, as requested by some commenters (see, e.g.,
Ex. 30-2986). Other commenters found the proposed definition of MSD
hazards circular (see, e.g., Exs. 30-3344 and 30-4674). The revised
definition addresses this concern, because it focuses on the magnitude,
frequency, and duration of identified risk factors and their
relationship to MSD hazards.
MSD incident means an MSD that is work related, requires time away
from work, restricted work, or medical treatment beyond first aid, or
involves MSD signs or MSD symptoms that last 7 or more consecutive
days. (See the discussion of the terms MSD signs and MSD symptoms
below.) The definition of MSD incident is new to the final rule. See
the summary and explanation section describing the provisions of
paragraph (e), in which the term ``MSD incident'' is used in
association with the standard's action trigger.
MSD signs are objective physical findings that an employee may be
developing an MSD. Examples of MSD signs are: decreased range of
motion; deformity; decreased grip strength; and loss of muscle
function. The final rule's definition is essentially the same as the
proposed definition, except for minor editorial revisions made for
clarity. Additional discussion of this term appears in the summary and
explanation for paragraph (d) regarding the reporting of MSD incidents,
paragraph (e), the action trigger, and the Health Effects section of
the preamble (Section V).
Most of the comments OSHA received on the list of examples of MSD
signs included in the proposal concerned the role of the health care
professional (HCP) and the phrase ``objective physical findings'' (see,
e.g., Exs. 30-3818, 30-3826, 30-3934, 30-2993, 30-3167, 30-3745, 30-
4814 and 30-434). These commenters argued that the rule should be
structured so that only an HCP, not the employer, can determine whether
a given MSD is associated with objective physical findings. The
Newspaper Association of America objected to the list of signs because
``[O]SHA has inexplicably chosen to provide only four examples of MSD
signs and leaves employers to guess at what may constitute objective
physical findings'' (Ex. 30-2986). In response, OSHA notes that
employers are always free to involve an HCP in their determinations.
However, OSHA does not believe that employers will generally have
difficulty deciding whether an MSD sign is related to an employee
report because, by definition, signs are visible indications observable
both by the employee and the employer.
MSD symptoms are defined in the final rule as physical indications
that an employee may be developing an MSD. Examples of MSD symptoms
are: pain, numbness, tingling, burning, cramping, and stiffness. The
final rule's list of examples is essentially the same as the list in
the proposal, except that it is more clearly written. Most of the
comments relating to this term have already been discussed above under
``musculoskeletal disorder.'' Additional discussion of this term
appears in the summary and explanation for paragraph (e) on the
reporting of MSD incidents.
Personal protective equipment (PPE) is the equipment employees wear
that provides a protective barrier between the employee and an MSD
hazard. Examples of PPE are vibration-reduction gloves and carpet
layer's knee pads. The final rule's definition is essentially identical
to the definition proposed, except that the word ``effective'' before
``protective barrier'' has been deleted because the effectiveness of
PPE depends on the circumstances in a particular workplace and is
therefore not appropriate for a definition. One commenter noted that
the definition of PPE was clear. Additional discussion relating to the
meaning of this term can be found in the summary and explanation of
paragraph (l).
Problem job means a job that the employer has determined poses an
MSD hazard to employees in that job. The definition of the term
``problem job'' has been changed from the definition in the proposal,
which defined a problem job as ``* * * a job in which a covered MSD is
reported. A problem job also includes any job in the workplace that
involves the same physical work activities and conditions as the one in
which the covered MSD is reported, even if the jobs have different
titles or classifications.'' (See the definition of the term ``job''
above.)
Commenters were concerned that the definition unnecessarily
expanded the scope of the standard (see, e.g., Exs. 32-206-1, 32-368-1,
30-294, 30-2208-1, 30-3284 and 31-336), or requested clarification of
ways an employer could use to determine when physical work activities
and conditions were the ``same'' (see, e.g., Ex. 30-3765).
In response, OSHA notes that the Agency intends the ``same job''
requirements to extend the protections provided by the standard to
employees who are fortunate enough not to have experienced an MSD
incident but who are in ``higher-risk'' jobs, as demonstrated by the
fact that one employee in the job has already experienced an incident
and the job has been determined to meet the action trigger. The
standard's ``same job'' requirements are preventive in nature and will
benefit workers in the job as well as saving the employer the costs
associated with the MSDs that are averted by fixing the jobs of other
employees in the same job. As to the concern about how an employer can
know which jobs are the same, OSHA believes that the Basic Screening
Tool will be useful in cases where deciding which jobs are the same is
difficult.
Risk factor, as used in this standard, means force, awkward
posture, repetition, vibration, and contact stress. The term replaces
the term ``ergonomic risk factors,'' which was defined in the proposed
rule. There was considerable comment in response to the definition of
``ergonomic risk factors'' in the proposed rule. Commenters stated that
[[Page 68433]]
the term was vague and too broad (see, e.g., Exs. 30-1011 and 30-2986)
and did not provide employers with enough information to allow them to
determine if the factors are present in particular jobs and, if so, the
duration of exposure to them (see, e.g., Ex. 30-2986). A large number
of commenters expressed concern that they would be unable to quantify
the risk factors in a job based on the amount of information provided
in the proposal (see, e.g., Exs. 30-1722, 30-3032, 30-3336, 30-3765,
30-3813 and 30-3866).
The concerns raised by commenters have largely been addressed by
the final rule, which limits the number of risk factors covered by the
standard to those most often associated with MSDs and additionally
provides clear definitions for each risk factor of the magnitude,
frequency, or duration at which exposure poses a potential risk (the
Basic Screen levels) and the level deemed to pose an MSD hazard (e.g.,
the levels indicated by the hazard identification tools in Appendices
D-1 and D-2).
Some commenters raised legal issues, i.e., the alleged vagueness of
the term ``risk factors'' and the lack of precise quantitative
estimates of the levels at which each risk factor poses risk (see,
e.g., Exs. 32-368-1 and 32-206-1), and the perceived need to establish
quantitative permissible exposure limits for the risk factors (see,
e.g., Ex. 30-3784). These issues are discussed at length in the Other
Stautory Issues and Legal Authority sections of this preamble.
Work practices are changes in the way an employee performs the
physical work activities of a job that reduce exposure to MSD hazards.
Work practice controls involve procedures and methods for safe work.
Examples of work practice controls for MSD hazards include:
(a) Using neutral work postures;
(b) Using lifting teams;
(c) Taking micro-breaks; and
(d) Avoiding lifts involving extended reaches or twisted torso.
(e) Conditioning or work-hardening programs.
The proposed rule defined work practices in essentially the same
way, except that OSHA has added a conditioning or work-hardening
program to the rule in response to comments in the record (see, e.g.,
Exs. 30-1902, 30-3686, 32-22, and 32-210, and 30-4137, Tr. 8720, Tr.
12472-12479). These commenters stated that they use these program to
protect newly assigned workers during the period when they are first
exposed to risk factors on the job. OSHA notes in the definition for
``work restrictions'' that conditioning and work-hardening programs are
not to be considered work restrictions for the purposes of this
standard.
In the Issues section of the proposal, OSHA asked for comment about
the appropriate work practices or controls employers could use to
prevent Computer Vision Syndrome (CVS). In response to this inquiry,
OSHA received several comments (see, e.g., Exs. 30-3032, 30-2387, 30-
2208). One commenter stated that controlling glare, providing adequate
lighting, well-designed software, and regularly shifting the static
fixed focal point of the eye are all approaches that have been used to
address CVS. Other commenters (see, e.g., Exs. 30-3032, 30-2208) urged
OSHA not to include CVS in the list of examples of MSDs in the final
rule. OSHA agrees that not enough is currently known about CVS and its
causes for the final rule to focus on it.
Work related means that an exposure in the workplace ``caused or
contributed'' to an MSD or ``significantly aggravated'' a pre-existing
MSD. ``Work-related'' was not defined in the proposal. The final rule
uses the term ``work related'' in the definition of an MSD incident. In
the proposed rule, OSHA used the term ``work relatedness'' in the
definitions of ``covered MSD'' and ``OSHA recordable MSD.''
A number of commenters objected to the term ``work-related'' in the
context of OSHA recordable injuries and illnesses because they believe
the term is so broad that it often includes non-work related MSDs (see,
e.g., Exs. 500-188, 30-2489, 31-336, 30-2834, 30-2986, 30-1722 and 30-
1037). For example, the Center for Office Technology argued that the
proposal was designed in a way that would permit a program to be
triggered by an episode of weekend overexertion that interfered with
work on Monday (Ex. 30-2208-2), and the International Council of
Shopping Centers (Ex. 30-2489) expressed the same concern. These
commenters are essentially objecting to OSHA's definition of a
recordable injury under Part 1904, the Agency's recordkeeping rule;
that rule defines a work-related injury as one caused, contributed to,
or aggravated by an event or exposure in the workplace, without regard
to the extent of the contribution of work to the injury.
Several participants urged OSHA not to include the concept of work
aggravation of a pre-existing MSD in the final rule (see, e.g., Exs.
30-629, 30-1037, 30-3159, 30-4185 and 31-336). Typical of those
comments was one by Uniservice, Inc. (Ex. 30-2834), which stated,
``[w]e will have to make changes to fix a job for a supposed MSD that
was not caused by workplace exposure in the first place [if OSHA
includes the significant aggravation definition in the standard].''
Other commenters focused their concern about including aggravation in
the concept of work-relatedness on back injuries because back pain is
so common both inside and outside the workplace (see, e.g., Exs. 30-
3784, 30-4185, 31-336 and 30-3937). The final rule does not rely on an
OSHA recordable injury or illness when defining an MSD incident; the
final rule's definition specifies what kinds of MSDs are included
(those involving restricted work, for example). OSHA believes that the
increased clarity of the final rule will alleviate many of these
commenters' concerns.
Work restriction protection (WRP) means the maintenance of the
earnings and other employment rights and benefits of employees who are
on temporary work restrictions. Benefits include seniority, insurance
programs, retirement benefits, and savings plans. In the proposal, OSHA
defined ``work restriction protection'' to mean:
the maintenance of the earnings and other employment rights and
benefits of employees who are on temporary work restriction. For
employees who are on restricted work activity, WRP includes
maintaining 100% of the after-tax earnings employees with covered
MSDs were receiving at the time they were placed on restricted work
activity. For employees who have been removed from the workplace,
WRP includes maintaining 90% of the after-tax earnings. Benefits
mean 100% of the non-wage-and-salary value employees were receiving
at the time they were placed on restricted work activity or were
removed from the workplace. Benefits include seniority, insurance
programs, retirement benefits and savings plans.
The language beginning with ``For employees'' and ending with
``from the workplace'' (outlined in the above quote) has been removed
from the final rule's definition. Additional discussion relating to
both the meaning of this term and the regulatory requirements on work
restriction protection can be found in the summary and explanation of
paragraph (r).
Work restrictions are defined as limitations, during the recovery
period, on an employee's exposure to MSD hazards. Work restrictions may
involve limitations on the work activities of the employee's current
job (light duty), transfer to temporary alternative duty jobs, or time
away from the workplace to recuperate. For the purposes of this
standard, temporarily reducing an employee's work requirements in a new
job in order to reduce muscle soreness
[[Page 68434]]
resulting from the use of muscles in an unfamiliar way is not a work
restriction. Further, the day an employee first reports an MSD is not
considered a day of work restriction, even if the employee is removed
from his or her regular duties for part of the day.
This definition is a revision of the proposed definition. The
proposed definition of work restriction included the sentence: ``To be
effective, work restrictions must not expose the injured employee to
the same MSD hazards as were present in the job giving rise to the
covered MSD.'' This sentence has been removed from the definition
because it is better suited to the summary and explanation for
paragraph (r). See the discussion of the comments received on Work
Restriction Protection in general above and in the summary and
explanation for paragraph (r).
You means the employer, as defined by the Occupational Safety and
Health Act of 1970 (29 U.S.C. 651 et seq.). The final rule's definition
is identical to the proposed definition (64 FR 66078). There were no
comments on this definition.
Several terms that were defined in the proposal are not used in the
final rule. They include ``manual handling jobs,'' ``manufacturing
jobs,'' and ``have knowledge.'' ``MSD management'' was also defined
separately in the proposal but is now discussed in the regulatory text
and summary and explanation for paragraph (p).
Some commenters suggested that OSHA define new terms, including the
term ``employee.'' The Alliance of American Insurers (AAI) (Ex. 30-
3751) objected to the proposal's cross-reference to the definition of
employee contained in the OSH Act. The Alliance asked OSHA to provide
additional clarification about who is or is not an employee under
various types of employer/employee relationships, such as employee
leasing arrangements. The AAI said: ``how is OSHA to make WRP
determinations? What if one entity is held to be responsible for WRP
but the other entity is responsible for workers' compensation
benefits?'' This issue is discussed in detail in the summary and
explanation for paragraph (r).
The DuPont SHE Excellence Center (Ex. 30-2134) recommended the
addition of a definition for workplace, commenting that in the proposed
rule:
``There is no definition of workplace incorporated in this
section [proposed definition of problem job], which creates more
confusion. Is the workplace the specific building the job is
located, the same physical site (which might contain several
buildings), or the entire company with all of its locations within
the U.S. and its territories? Some jobs take place out-of-doors, in
varied locations which can move from place to place. How are these
jobs considered under the ``problem job'' definition?''
The final rule makes clear that the physical establishment that
houses the problem job, or to which the injured employee and other
employees in the same job report, limits the program activities
required by the standard. The standard does not impose corporate-wide
obligations on businesses that have multiple establishments. Instead,
the standard is job-based in the first instance, i.e., employers are
only required to implement the ergonomics program in those jobs
identified as problem jobs. It is establishment-based in the second
instance, i.e., employers are only required to include in their program
the problem job (and the workers in them) within the establishment to
which the problem job is ``attached.'' This means that, where the
workforce is mobile, the establishment to which the injured employee
reports would be considered the establishment, for the purposes of the
standard. Since the standard requires employers to extend the
standard's protections to all employees in the same job, the employer
is required to ``fix'' the MSD hazards in the workstations or work
environments of all employees in the same job who are located in, or
report to, the same establishment.
For the purposes of the standard, OSHA defines an establishment as
a single physical location where business is conducted or where
services or industrial operations are performed. For activities where
employees do not work at a single physical location, such as
construction; transportation; communications, electric, gas and
sanitary services; and similar operations, the establishment is
represented by main or branch offices, terminals, stations, etc., that
either supervise such activities or are the base from which personnel
carry out these activities.
One commenter (Exs. 30-2825 and 30-3332) suggested that OSHA add a
definition of repetitive motion jobs to the final rule. OSHA does not
believe such a definition is necessary because the final rule contains
clear definitions of each of the risk factors (see the Basic Screening
Tool in Table 1).
Several commenters asked OSHA to clarify the definitions of
industries covered and exempted from the final rule (see, e.g., Exs.
30-1897, 30-3818 and 30-4716). For example, the Honorable James Talent,
Chairman of the U.S. House of Representatives Committee on Small
Business (Ex. 30-1897), noted that the proposed rule did not apply to
agriculture, construction, or maritime operations, but did not clarify
each of these terms. Paragraph (b) of the final rule provides clear
definitions of the standard's scope and explicitly states that it does
not apply to maritime, agricultural, railroad, or construction
employment.
Finally, some commenters suggested that OSHA define the term
recovery period, which was used in the definition of work restriction
protection (WRP) (see, e.g., Exs. 30-3749 and 30-3344). OSHA has not
done so because this term is used in the final rule in its everyday
sense, and is therefore clear on its face.
V. Health Effects
In this section, OSHA presents the evidence contained in the
rulemaking record that addresses the causal relationship between
exposure to biomechanical risk factors at work and an increased risk of
developing musculoskeletal disorders (MSDs). This evidence consists of
epidemiological studies of exposed workers in diverse occupational
settings, biomechanical studies describing the relationships between
exposure to risk factors and associated forces imposed on
musculoskeletal tissue, studies of tissue pathology describing the
kinds of tissue alterations that have been seen to result from such
forces, and medical and diagnostic information relating to MSDs. In
making its findings from this evidence, OSHA is relying in part on the
extensive scientific evidence presented in the detailed Health Effects
Appendices to the proposal (64 FR 65865-65926) (Ex. 27-1), located on
OSHA's webpage at http://www.osha.gov and summarized in this section.
In addition, OSHA's analysis includes results from several other
studies placed into the rulemaking record after publication of the
proposed rule, as well as comment and testimony from many distinguished
scientific experts.
This section is divided into the following seven parts:
Part A, Description of Biomechanical Risk Factors;
Part B, Overview of the Health Effects Evidence;
Part C, Evidence on Neck and Shoulder Disorders;
Part D, Evidence on Upper Extremity Disorders;
Part E, Evidence on Back Disorders;
Part F, Evidence on Lower Extremity Disorders; and
Part G, OSHA's Response to Issues Raised in the
Rulemaking.
[[Page 68435]]
A. Biomechanical Risk Factors
Biomechanical risk factors are the aspects of a job or task that
impose a physical stress on tissues of the musculoskeletal system, such
as muscles, nerves, tendons, ligaments, joints, cartilage, spinal
discs, or (in the case of hand-arm vibration syndrome) blood vessels of
the upper extremities. To accomplish motion and work, muscle, nerves,
connective tissue, and skeleton are affected by a number of external
and internal physical demands causing metabolic and compensatory tissue
reactions. External demands can include direct pressure on tissues or
tissue friction. Internal responses can include inflammatory responses
to tissue injury, neurochemical changes, and altered metabolism. The
consequences of these external and internal demands associated with
work activities can include a spectrum of symptoms or clinical
findings. Although some types of tissue, like skeletal muscle, have the
ability to recover after an injury that does not physically disrupt the
tissue, exceeding tissue limits may result in permanent damage to a
tissue. However, skeletal muscle is just one type of tissue that can be
affected; other tissues like tendon, ligament, nerve, and cartilage can
also be damaged by exposure to excessive physical task factors. These
tissues, unlike skeletal muscle, do not have the same capacity for
recover and repair after injury. (Each part of this Health Effects
section briefly summarizes the pathogenesis of MSDs; OSHA's Health
Effects Appendices (Ex. 27-1), developed for the proposed rule,
contains detailed discussions of the scientific literature describing
the pathogenesis of MSDs).
The biomechanical risk factors addressed by this final rule are
repetition, force, awkward postures, vibration to the upper extremity
(i.e., segmental vibration), and contact stress. In occupations where
an increased prevalence or incidence of MSDs has been observed, these
risk factors frequently occur in combination; the level of risk
associated with exposure depends on the intensity and duration of
exposure as well as the amount of recovery time available to the
strained tissues for repair. Soft tissues of the musculoskeletal system
will develop tolerance to physical loading if sufficient recovery time
is provided. Without adequate recovery time, affected tissues can
accumulate damage or become more prone to failure. The need for
adequate recovery time between exposure events means that the pattern
of exposure also has an important influence on risk. The biomechanical
risk factors covered in the final rule are force, repetition, awkward
postures, contact stress, and segmental vibration; the basic screening
tool in the final rule describes criteria for each of these risk
factors that identifies those jobs where there is a potential risk of
MSDs. Each of these risk factors is described below.
Force
Force refers to the amount of physical effort that is required to
accomplish a task or motion. Force also refers to the degree of loading
to muscles and other tissues as a result of applying force to perform
work. Tasks or motions that require application of higher force place
higher mechanical loads on muscles, tendons, ligaments, and joints (Ex.
26-2). The force required to complete a movement increases when other
risk factors are also involved. For example, more physical effort may
be needed to perform tasks when the speed or acceleration of motions
increases, when vibration is present, or when the task also requires
awkward postures. Hand tools that require use of pinch grips require
more forceful exertions to manipulate the tool than do those that
permit use of power grips.
Relationships among external loads, internal tissue loads, and
mechanical and physiological responses have also been studied
extensively, using simulation, direct instrumentation, indirect
instrumentation, and epidemiological studies. In a report on the
Research Base of Work-Related Musculoskeletal Disorders prepared by the
National Research Council (NRC) in response to a request from the
National Institutes of Health (NIH) (Ex. 26-37), the steering committee
provides some rationale for evaluating and controlling biomechanical
risk factors, specifically force:
The concept of force can be generalized to encompass
numerous ways of measuring and characterizing external loads. For
example, force can be measured in terms of the weight of parts, tool
reaction force, perceived exertion, muscle electrical activity, or
observer ratings.
Internal loads can be estimated by using external
loads. For example, a worker must bend or stoop to lift something
from the floor; a worker will exert more force on a stiff keyboard
than a light touch keyboard. Understanding these relationships
allows prediction of internal loads.
Predicted internal loads generally agree with measured
internal and external loads. For example, measurements of muscle
loads during activity using electromyography generally agree with
predicted values.
Force can be assessed qualitatively or quantitatively. Quantitative
measures include strain gauges, spring scales, and electromyography to
measure muscle activity. A qualitative assessment of force is based on
direct observation of the amount of physical exertion required to
complete a task, and is usually graded on an ordinal scale (i.e., low,
medium, high).
Repetition
Repetition refers to the frequency with which a task or series of
motions are repeated with little variation in movement. Although force
and/or awkward postures can combine with repetition to increase the
risk of MSDs over that of repetition alone, acceleration and velocity
of repetitive movement are also important considerations in that they
may ``cause damage that would not be predicted by muscle forces or
joint angles alone'' (Washington State CES, p.20, Ex. 500-71-93).
Repetitive motions occur frequently in manufacturing operations
where production and assembly processes have been broken down into
small sequential steps, each performed by different workers. However,
it also applies to many manual handling operations, such as warehouse
operations and baggage handling. Repetition is typically assessed by
direct observation or videotaping of job tasks. The intensity of
exposure is usually expressed as a frequency of motion or as a percent
of task cycle time, where a cycle is a pattern of motions.
Awkward Postures
Awkward postures refer to positions of the body (e.g., limbs,
joints, back) that deviate significantly from the neutral position
while job tasks are being performed. For example, when a person's arm
is hanging straight down (i.e., perpendicular to the ground) with the
elbow close to the body, the shoulder is said to be in a neutral
position. However, when employees are performing overhead work (e.g.,
installing or repairing equipment, grasping objects from a high shelf)
their shoulders are far from the neutral position. Other examples
include wrists bent while typing, bending over to grasp or lift an
object, twisting the back and torso while moving heavy objects, and
squatting. Awkward postures often are significant contributors to MSDs
because they increase the exertion and the muscle force that is
required to accomplish the task, and compress soft tissues like nerves,
tendons, and blood vessels. As used in the final rule's basic screening
tool, awkward postures may be either static postures held for
[[Page 68436]]
prolonged periods of time, or they may occur repetitively.
Awkward posture is the primary ergonomic risk factor to which
employees are exposed when the height of working surfaces is not
correct. Working at surfaces that are too high can affect several parts
of the body. Employees may have to lift and/or move their shoulders,
elbows and arms (including hands and wrists) into uncomfortable
positions to perform the job tasks on higher surfaces. For example,
employees may have to raise their shoulders or move their elbows out
from the side of their body to do a task on a high working surface.
Also, they may have to bend their heads and necks to see the work they
are doing.
Working surfaces that are too high usually affect the shoulders.
The muscles must apply considerably more contraction force to raise and
hold the shoulders and elbows out to the side, particularly if that
position also must be maintained for more than a couple of seconds. The
shoulder muscles fatigue quickly in this position.
On the other hand, when surfaces are too low, employees may have to
bend their backs and necks to perform their tasks while hunched over
the working surface. They may also have to reach down with their arms
and backs to do the tasks. Where working surfaces are very low,
employees may have to kneel or squat, which places very high forces on
the knees to maintain the position and the weight of the body. Working
surfaces that are too low usually affect the lower back and
occasionally the neck.
Working in awkward postures increases the amount of force needed to
accomplish an exertion. Awkward postures create conditions where the
transfer of power from the muscles to the skeletal system is
inefficient. To overcome muscle inefficiency, employees must apply more
force both to initiate and complete the motion or exertion. In general,
the more extreme the postures (i.e., the greater the postures deviate
from neutral positions), the more inefficiently the muscles operate
and, in turn, the more force is needed to complete the task. Thus,
awkward postures make forceful exertions even more forceful, from the
standpoint of the muscle, and increase the amount of recovery time that
is needed.
Awkward postures are assessed in the workplace by observing joint
angles during the performance of job tasks. Observed postures can be
compared qualitatively to diagrams of awkward postures, such as is done
in many job analysis tools, or angles can be measured quantitatively
from videotape recordings.
Contact Stress
As used in many ergonomics texts and job analysis tools, contact
stress results from activities involving either repeated or continuous
contact between sensitive body tissue and a hard or sharp object. The
basic screening tool in the final rule includes a particular type of
contact stress, which is using the hand or knee as a hammer (e.g.,
operating a punch press or using the knee to stretch carpet during
installation). Thus, although contact stress is covered in the final
rule as a single risk factor, it is really a combination of force and
repetition. Mechanical friction (i.e., pressure of a hard object on
soft tissues and tendons) causes contact stress, which is increased
when tasks require forceful exertion. The addition of force adds to the
friction created by the repeated or continuous contact between the soft
tissues and a hard object. It also adds to the irritation of tissues
and/or to the pressures on parts of the body, which can further inhibit
blood flow and nerve conduction.
Contact stress commonly affects the soft tissue on the fingers,
palms, forearms, thighs, shins and feet. This contact may create
pressure over a small area of the body (e.g., wrist, forearm) that can
inhibit blood flow, tendon and muscle movement and nerve function. The
intensity of exposure to contact stress is usually determined
qualitatively through discussion with the employee and observation of
the job.
Segmental Vibration
Vibration refers to the oscillatory motion of a physical body.
Segmental, or localized vibration, such as vibration of the hand and
arm, occurs when a specific part of the body comes into contact with
vibrating objects such as powered hand tools (e.g., chain saw, electric
drill, chipping hammer) or equipment (e.g., wood planer, punch press,
packaging machine).
Although using powered hand tools (e.g., electric, hydraulic,
pneumatic) may help to reduce risk factors such as force and repetition
over using manual methods, they can expose employees to vibration.
Vibrating hand tools transmit vibrations to the operator and, depending
on the level of the vibration and duration of exposure, may contribute
to the occurrence of hand-arm vibration syndrome or Raynaud's
phenomenon (i.e. vibration-induced white-finger MSDs) (Ex. 26-2).
The level of vibration can be the result of bad design, poor
maintenance, and age of the powered hand tool. For example, even new
powered hand tools can expose employees to excessive vibration if it
they do not include any devices to dampen the vibration or in other
ways shield the operator from it. Using vibrating hand tools can also
contribute to muscle-tendon contractile forces owing to operators
having to use increased grip force to steady tools having high
vibration.
Vibration from power tools is not easy to measure directly without
the use of sophisticated measuring equipment. However, vibration
frequency ratings are available for many recently designed hand tools.
Based on the whole of the scientific literature available at the
time of the proposal, OSHA also identified prolonged sitting and
standing (a form of static posture) and whole-body vibration as risk
factors for MSDs; in addition, OSHA identified cold temperatures as a
risk factor modifier because it could require workers to increase the
force necessary to perform their jobs (such as having to grip a tool
more tightly) (64 FR 65865-65926) (Ex. 27-1). The final rule does not
explicitly include these risk factors. For prolonged standing and
sitting, and for cold temperatures, although there is evidence of an
increased risk of MSDs with exposure (e.g., see Skov, Ex. 26-674), the
available evidence did not permit the Agency to provide sufficient
guidance to employers and employees on the levels of exposure that
warrant attention. For whole-body vibration, there was substantial
evidence of a causal association with low back disorders (e.g., see
NIOSH 1997); however, heavy equipment and trucks, the most common
sources of whole-body vibration, are seldom rated for vibration
frequencies and intensities. In addition, measurement of whole-body
vibration levels requires special equipment and training that would be
difficult for most employers to obtain. Therefore, OSHA determined that
it was appropriate not to include whole-body vibration in the final
rule at this time.
For the biomechanical risk factors of force, repetition, awkward
postures, segmental vibration, and contact stress, OSHA has concluded
that strong evidence exists for a positive relationship between
exposure to these risk factors and an increased risk of developing
MSDs, based on the scientific evidence and testimony described in this
section of the final rule's preamble. The risk factors identified by
the Agency as being causally related to the development of MSDs and
that are covered in the final rule are the same risk factors that have
[[Page 68437]]
been addressed by other reputable scientific and regulatory bodies,
both nationally and internationally, who face the challenge of either
reducing the incidence of MSDs or contributing to the scientific basis
for these actions. The two most current and thorough reviews on this
topic are NIOSH's Critical Review of Epidemiologic Evidence for Work-
Related Musculoskeletal Disorders of the Neck, Upper Extremity, and Low
Back (Bernard, 1997; Ex. 26-1) and the National Research Council/
National Academy of Science's Work-Related Musculoskeletal Disorders:
Report, Workshop Summary, and Workshop Papers (1999; Ex. 26-37).
NIOSH's review focused on repetition, force, posture, and vibration
when evaluating epidemiologic evidence for the neck, shoulder, elbow,
and hand/wrist. For the low-back, the authors looked at the evidence
for heavy physical work, lifting and forceful movements, bending and
twisting (awkward postures), whole body vibration and static work
postures. The ``work factors'' identified by the NRC in their report on
Work-Related Musculoskeletal Disorders are the same as the
``biomechanical risk factors'' identified by OSHA. Although terms may
differ depending upon the part of the body being described, it is easy
to see the relationship between heavy physical work and lifting and the
concept of force/exertion to the back, for example .
The Steering Committee Report for the NRC workshop on ``Examining
the Research Base (for Work-Related MSDs)'', participants agreed there
is
``enough scientific evidence to confirm that strain on
musculoskeletal tissue increases when humans perform activities that
involve forceful manual exertions, awkward postures, repetitive or
prolonged exertions, exposure to vibrations and exposure to cold
temperatures.''
However, in a separate paper prepared for the NRC/NAS workshop,
Radwin and Lavender also discuss ``workplace layout,'' ``interactions
with objects,'work scheduling'' and other ``workplace design factors,''
as factors that these authors, as well as others, have studied in
relation to MSDs. Although there is strong agreement on biomechanical
factors associated with MSDs, the science is still evolving with regard
to other types of factors. Thus, when sources refer to biomechanical
risk factors, all literature reviewed from the rulemaking record
identified the same basic risk factors, all essentially related to
force/exertion, repetition, posture and vibration.
Literature reviews published in the scientific literature also
evaluate these same risk factors. Literature reviews of this type use
selection criteria to capture the best-designed studies with a
particular focus, usually risk factors associated with a specific type
of disorder, for analysis. Burdorf and Sorock reviewed 35 articles that
evaluated risk factors for back disorders and concluded that lifting or
carrying loads (force), whole-body vibration and frequent bending and
twisting (awkward postures) were consistently related to work-related
low-back disorders (1997; Ex. 500-71-24). In a systematic review of 31
studies, Hoogendoorn et al (1997; Ex. 500-71-32) found strong evidence
exists for manual materials handling, bending and twisting (awkward
posture), and whole-body vibration as risk factors for back pain, and
moderate evidence exists for patient handling and physical work.
In their review of the literature on the role of physical load
factors in carpal tunnel syndrome, Viikari-Juntura and Silverstein
found an association with carpal tunnel syndrome and forceful,
repetitive work, extreme wrist postures and vibration (1999; Ex. 32-
339-1-56). Other authors (Ariens et al., 2000; Ex. 500-71-23) found a
relationship between neck pain and neck flexion, arm force, arm
posture, duration of sitting, twisting or bending of the trunk, hand-
arm vibration, and workplace design.
In both written submissions to the record, and in oral testimony,
numerous scientific experts confirmed and substantiated OSHA's position
that sufficient scientific evidence exists, and is contained in the
record, to conclude that workplace exposure to the biomechanical risk
factors described above increase the risk for work-related MSDs (Exs.
37-1; 37-2; 37-3; 37-6; 37-8; 38-9; 37-10; 37-13; 37-15; 37-16; 37-17;
37-18; 37-21; 37-27; 37-28; 26-37). Scientists who testified at the
hearings also confirmed that each of these risk factors are linked to
an increased risk of developing an MSD in exposed workers (Dr. Don
Chaffin, University of Michigan, Tr 8254; Dr. Nicholas Warren,
University of Connecticut Health Center, Tr.1084-85; Dr. Martin
Cherniak, Ergonomics Technology Center of Connecticut, Tr. 1128; Dr.
Richard Wells, University of Waterloo, Tr. 1353-54; Dr. Robert
Harrison, Tr. 1648; Dr. Amadio, Mayo Clinic, Tr. 9815, 98; Dr. Eckardt
Johanning, Eastern New York Occupational and Environmental Health
Center, Tr. 16831-33; Dr. Jim McGlothlin, Purdue University, Dr.
Malcolm Pope, Tr. 16808; Dr. Margit Bleeker, Tr. 16826). This written
and oral testimony from scientific experts provides a compelling case
establishing the link between exposure to biomechanical risk factors
and an increased risk of MSD incidence.
OSHA heard from a number of scientists and physicians during it's
hearing with comments along the lines of that by Dr. Robert Harrison,
from the University of California (Tr. 1649-50):
The jobs and tasks my patients are performing are the ones the
literature has identified as high-risk jobs with exposure to many of
the same physical risk factors. In fact, my patients are exposed to
the identical physical work activities and conditions that have been
identified by OSHA as causing excessive exposure to force, frequent
repetition, awkward posture, contact stress, vibration and cold
temperatures.
The record contains many US and international regulations and
guidelines that reflect the same biomechanical risk factors addressed
in the final rule; some are listed below:
National Research Council. (1999) Work-Related
Musculoskeletal Disorders: Report, Workshop Summary, and Workshop
Papers. National Academy Press. (Ex. 26-37);
National Institute for Occupational Safety and Health.
(1997) Musculoskeletal Disorders and Workplace Factors. Centers for
Disease Control and Prevention (Ex. 26-1);
National Institute for Occupational Safety and Health.
(1998) Elements of Ergonomics Programs, A Primer Based on Workplace
Evaluations of Musculoskeletal Disorders. (Ex. 26-2);
European Agency for Safety and Health at Work. Work-
related neck and upper limb musculoskeletal disorders (1999). (Ex.500-
71-28);
Department of Labor and Industries, Washington State. (5/
25/00) Concise Explanatory Statement, WAC 296-62-051, Ergonomics (Ex.
500-71-93);
Ergonomics for the Prevention of Musculoskeletal
Disorders, Swedish National Board of Occupational Safety and Health on
Ergonomics for the Prevention of Musculoskeletal Disorders. AFS 1998:1;
(Ex. 500-71-14);
National Codes of Practice for the Prevention of
Occupational Overuse Syndrome-Worksafe Australia [NOHSC:2013(1994)],
(Ex. 500-71-2);
National Standard for Manual Handling and National Code of
Practice for Manual Handling, Worksafe Australia. 1990 (Ex. 500-71-4);
Occupational Overuse Syndrome: Guidelines for Prevention
and Management, Occupational Safety and Health Services, Department of
Labor, New Zealand (Ex. 500-71-12);
Ergonomics (MSI) Requirements, British Columbia, Canada
(Ex. 32-339-1-6);
[[Page 68438]]
Regulations and Code of Practice, (Manual Handling)
Occupational Health and Safety Regulations 1988. Victoria, Canada. (Ex.
500-71-17);
European Communities Council Directive on Manual Handling
(Ex. 32-339-1-12);
American Conference of Governmental Industrial Hygienists,
Threshold Limit Value (TLV) Committee, Nov. 13, 1999. Notice of Intent
to Establish a Threshold Limit Value, Hand Activity Level (Ex. 32-339-
1-63);
American Conference of Governmental Industrial Hygienists.
1987. Ergonomic Interventions to Prevent Musculoskeletal Injuries in
Industry (Ex. DC-386, Tr. 16291-335);
American Industrial Hygiene Association. 1994. Ergonomic
Guide Series (Ex. 32-133-1);
American National Standards Institute (ANSI) draft
Ergonomic Standard, Z-365 (1998) (Ex.26-1264).
Furthermore, the vast majority of the many job evaluation tools
found in the record and reviewed by the Agency collectively address
these same risk factors covered under the final rule (Exs. 26-521, 26-
1421, 26-1008, 26-883, 26-500-71-92). Also, studies using specific
interventions to reduce biomechanical load address these same risk
factors (see section VI, Risk Assessment).
B. Overview of Evidence of Health Effects for Work-Related
Musculoskeletal Disorders
A substantial body of scientific evidence supports OSHA's effort to
provide workers with ergonomic protection (see the Health Effects
Appendix of the proposal preamble, and the Health Effects Summary, Risk
Assessment, and Significance of Risk sections of this preamble, below).
This evidence strongly supports two basic conclusions: (1) there is a
positive relationship between exposure to biomechanical risk factors
and development of work-related musculoskeletal disorders and (2)
ergonomics programs and specific ergonomic interventions can reduce
these risks. Although it is recognized that many individual and non-
biomechanical workplace factors (such as psychosocial factors) also
contribute to the total risk, exposure to biomechanical factors has
been shown to contribute to the risk independently from other causal
factors; these findings support the appropriateness of designing
interventions that reduce exposures to biomechanical factors as a
strategy for reducing risk of MSDs.
This section presents an overview of the health evidence summarized
from the proposal (64 FR 65865-65926; Ex. 27-1), updates that evidence
with more recent information brought to the Agency's attention during
the rulemaking process, and presents some additional information and
conclusions as to the adequacy and quality of the overall scientific
data base used for the final rule. In developing its review of the
scientific evidence, the Agency has relied on almost 200
epidemiological studies that describe the prevalence or incidence of
MSDs among workers who have been exposed to biomechanical risk factors.
Several of these (see Part G of the Health Effects sections)
simultaneously evaluated the effects of biomechanical and psychosocial
factors in the workplace; these studies generally represent the most
recent and best-designed epidemiological studies.
In addition to epidemiological studies, OSHA has reviewed a
considerable amount of information and studies that describe the
biomechanical aspects of MSD etiology, along with studies that have
been conducted to elucidate the physiological responses of tissues to
biomechanical stress. Much of this information was presented in detail
in OSHA's Health Effects Appendices (Ex. 26-1), prepared at the time of
the final rule. OSHA has since supplemented this information with
additional material contained in the rulemaking record.
In compiling and evaluating the scientific evidence for its
proposed ergonomic program standard OSHA made use of the two major
reviews of the evidence for work-relatedness of MSDs available at that
time, NIOSH's ``Musculoskeletal Disorders and Workplace Factors: A
Critical Review of the Epidemiologic Evidence for Work-Related
Musculoskeletal Disorders of the Neck, Upper Extremity, and Low Back''
(Bernard, 1997; Ex. 26-1) and the National Research Council/National
Academy of Sciences' ``Workshop on Work-Related Musculoskeletal
Injuries: The Research Base'' (Ex. 26-37). Because OSHA's reliance on
these two important works generated a considerable amount of comment
and testimony, these two reviews are described in detail here. However,
throughout this Health Effects section, OSHA has made use of several
other scientific reviews of the literature as well.
The National Institute for Occupational Safety and Health (NIOSH)
conducted a scientific review of hundreds of peer-reviewed studies, and
evaluated the evidence for work-related musculoskeletal disorders of
the neck, upper extremity, and low back (Bernard, 1997; Ex.26-1). The
focus of this review was the epidemiology literature, the goal of which
is to identify factors that are associated (positively or negatively)
with the development of recurrence of adverse medical conditions. This
evaluation and summary of the epidemiologic evidence focuses chiefly on
disorders that affect the neck and the upper extremity, including
tension neck syndrome, shoulder tendinitis, epicondylitis, carpal
tunnel syndrome, and hand-arm vibration syndrome, which have been the
most extensive studies in the epidemiologic literature. The document
also reviews studies that have dealt with work-related back pain and
that address the way work organization and psychosocial factors
influence the relationship between exposure to physical factors and
work-related MSDs. The literature about disorders of the lower
extremity is outside the scope of the NIOSH review, and OSHA has done
its own analysis of that literature. The NIOSH work is the most
comprehensive review of this scientific literature to date.
A search strategy of bibliographic databases identified more than
2,000 studies. Studies were included if they evaluated exposure so that
some inference could be drawn regarding repetition, force, extreme
joint posture, static loading or vibration, and lifting tasks. Studies
in which exposure was measured or observed and recorded for the body
part of concern were considered superior to studies that used self-
reports or occupational/job titles as surrogates for exposure.
Because of the focus on the epidemiology literature, studies that
were laboratory-based or that focused on MSDs from a biomedical
standpoint, dealt with clinical treatment of MSDs, or had other
nonepidemiologic orientation were eliminated from further consideration
for this document. This strategy yielded over 600 studies for inclusion
in the detailed review process. Population-based studies of MSDs, case-
control studies, cross-sectional studies, longitudinal cohort studies,
and case series were included.
The first step in the analytical process was to classify the
epidemiologic studies by the following criteria:
The participation rate was 70%. This
criterion limits the degree of selection bias in the study.
The health outcome was defined by symptoms and physical
examination. This criterion reflects the preference of most
reviewers to have health outcomes that are defined by objective
criteria.
The investigators were blinded to health or exposure
status when assessing health or exposure status. This criterion
limits
[[Page 68439]]
observed bias in classifying exposure or disease.
The joint (part of body) under discussion was subjected
to an independent exposure assessment, with characterization of the
independent variable of interest (such as repetition or repetitive
work). Studies that used either direct observation or actual
measurements of exposure were considered to have a more accurate
exposure classification scheme, whereas studies that exclusively
used job title, interviews, or questionnaire information were
assumed to have less accurate exposure information.
During review of the studies, the greatest qualitative weight was
given to studies that had objective exposure assessments, high
participation rates, physical examinations, and blinded assessment of
health and exposure status.
The second step of the analytical process was to divide the studies
into those with statistically significant associations between
exposures and health outcomes and those without statistically
significant associations. The associations were then examined to
determine whether they were likely to be substantially influenced by
confounding or other selection bias (such as survivor bias or other
epidemiologic pitfalls that might have a major influence on the
interpretation of the findings). These include the absence of
nonrespondent bias and comparability of study and comparison groups.
The third step of the analytical process was to review and
summarize studies with regard to the epidemiologic criteria for
causality: strength of association, consistency in association,
temporal association, and exposure-response relationship. No single
epidemiologic study will fulfill all criteria to answer the question of
causality. However, results from epidemiologic studies can contribute
to the evidence of causality in the relationship between workplace risk
factors and MSDs. The exposures examined for the neck and upper
extremity were repetition, force, extreme posture, and segmental
vibration.
Using the epidemiologic criteria for causality as the framework,
the evidence for a relationship between workplace factors and the
development of MSDs from epidemiologic studies is classified into one
of the following categories: strong evidence of work-relatedness,
evidence of work-relatedness, insufficient evidence of work-
relatedness, evidence of no effect of work factors. The amount and type
of evidence required for each category is described below:
Strong evidence of work-relatedness. A causal relationship is
known to be very likely between intense or long-duration exposure to
the specific risk factor(s) and MSD when the epidemiologic criteria
of causality are used. A positive relationship has been observed
between exposure to the specific risk factor and MSD in studies in
which chance, bias, and confounding factors could be ruled out with
reasonable confidence in at least several studies.
Evidence of work-relatedness. Some convincing epidemiologic
evidence shows a causal relationship when the epidemiologic criteria
of causality for intense or long-duration exposure to the specific
risk factor(s) and MSD are used. A positive relationship has been
observed between exposure to the specific risk factor and MSDs in
studies in which chance, bias, and confounding factors are not the
likely explanation.
Insufficient evidence of work-relatedness. The available studies
are of insufficient number, quality, consistence, or statistical
power to permit a conclusion regarding the presence or absence of a
causal association. Some studies suggest a relationship to specific
risk factors, but chance, bias, or confounding may explain the
association.
Evidence of no effect of work factors. Adequate studies
consistently show that the specific workplace risk factor(s) is not
related to development of MSD.
The above framework provides an indication of the selection
criteria NIOSH used in identifying studies for inclusion in their
review. Studies were included if the exposed and referent populations
were well defined, and if they involved neck, upper-extremity, and low-
back MSDs measured by well-defined, explicit criteria determined before
the study. Studies whose primary outcomes were clinically relevant
diagnostic entities, generally had less misclassification and were
likely to involve more severe cases. Studies whose primary outcomes
were the reporting of symptoms generally had more misclassification of
health status and a wider spectrum of severity.
Care should be taken when interpreting some study results regarding
individual workplace factors of repetition, force, extreme or static
postures, and vibration. As Kilbom (1994; Ex. 26-1352) stated, these
factors occur simultaneously or during alternating tasks within the
same work, and their effects concur and interact. A single odds ratio
(OR) for an individual risk factor may not accurately reflect the
actual association, as not all of the studies derive ORs for
simultaneously occurring factors. Thus these studies were not only
viewed individually (taking into account good epidemiologic principles)
but together for making broader interpretations about epidemiologic
causality. Many investigators did not examine each risk factor
separately but selected study and comparison groups based on
combinations of risk factors (such as workers in jobs involving high
force and repetition compared with workers having no exposure to high
force and repetition.)
Based on the epidemiologic criteria described above, NIOSH made the
following findings:
Strong evidence of work-relatedness exists for the following
associations:
High levels of static contraction, prolonged static loads,
extreme working postures involving the neck/shoulder muscles and an
increased risk for neck/shoulder MSDs;
Exposure to a combination of risk factors (e.g., force and
repetition, force and posture) and CTS;
Job tasks that require a combination of risk factors
(e.g., highly repetitious, forceful hand/wrist exertions) and hand/
wrist tendinitis;
High level exposure to hand-arm vibration and vascular
symptoms of hand-arm vibration syndrome;
Work-related lifting and forceful movements;
Exposure to whole-body vibration and low-back disorder.
2. Evidence exists for the following associations:
Highly repetitive work and neck and neck/shoulder MSDs,
considering both repetitive neck movements (using frequency and
duration of movements) and repetitive work involving continuous arm or
hand movements;
Forceful exertion and neck MSDs, with ``forceful work''
involving forceful arm or hand movements, which generate loads to the
neck/shoulder area;
Highly repetitive work and shoulder MSDs;
Repeated or sustained shoulder postures with greater than
60 degree of flexion or abduction and shoulder MSDs;
Highly repetitive work, both alone and in combination with
other factors and carpal tunnel syndrome;
Work involving hand/wrist vibration and CTS;
Any single factor (repetition, force and posture) and
hand/wrist tendinitis;
Work-related awkward postures and low-back disorders.
3. Insufficient evidence of work-relatedness exists for the
following associations:
Vibration and neck disorders;
Force and shoulder MSDs;
Extreme posture and CTS.
The NIOSH review (Bernard, 1997; Ex. 26-1) is an authoritative,
systematic, critical review of the epidemiologic evidence regarding
work-related risk
[[Page 68440]]
factors and their relationship to MSDs of the neck, shoulder, elbow,
hand/wrist, and low back. In considering its purpose, the authors
state:
This review of the epidemiologic literature may assist national
and international authorities, academics, and policy makers in
assessing risk and formulating decisions about future research or
necessary preventive measures.
In 1998, the National Institutes of Health asked the National
Academy of Sciences/National Research Council (NRC) to assemble a group
of experts to examine the scientific literature relevant to the work-
related musculoskeletal disorders of the lower back, neck and upper
extremities. A steering committee was convened to design a workshop, to
identify leading researchers on the topic to participate, and to
prepare a report based on the workshop discussions and their own
expertise. Additionally, the steering committee was asked to address,
to the extent possible, a set of seven questions posed by Congress on
the topic of musculoskeletal disorders. The steering committee includes
experts in orthopedic surgery, occupational medicine, epidemiology,
ergonomics, human factors, statistics, and risk analysis (NRC, 1999;
Ex. 26-37). Note: The steering committee's report was published in
1998, and was referred to in OSHA's proposal as Ex. 26-37. In the final
rule, Ex. 26-37 refers to the final report, (Work-Related
Musculoskeletal Disorders: Report, Workshop Summary, and Workshop
Papers, National Research Council, 1999; Ex. 26-37), which includes the
steering committee's report, a summary of the proceedings of the 2-day
workshop (Work-Related Musculoskeletal Injuries: The Research Base),
and the workshop papers.
The charge to the steering committee, reflected in the focus of the
workshop, was to examine the current state of the scientific research
base relevant to the problem of work-related musculoskeletal disorders,
including factors that can contribute to such disorders, and strategies
for intervention to ameliorate or prevent them. The NAS/NRC organized
their examination of the evidence of factors that potentially
contribute to musculoskeletal disorders:
(1) Biological responses of tissues to biomechanical stressors;
(2) Biomechanics of work stressors, considering both work and
individual factors, as well as internal loads;
(3) Epidemiologic perspectives on the contribution of physical
(biomechanical) factors;
(4) Non-biomechanical (e.g., psychological, organizational, social)
factors; and
(5) Interventions to prevent or mitigate musculoskeletal disorders.
For four of these topics, discussions at the workshop centered on a
paper (or papers) commissioned for the workshop, followed by the
comments of invited discussants. For the epidemiology of physical
factors, the steering committee used a panel format to take advantage
of a recent review of this literature, the NIOSH review, published in
1997, and previously discussed here.
Use of this broad approach provided for the examination of evidence
from both basic and applied science and a wide variety of
methodologies, and considered sources of evidence that extend well
beyond the epidemiologic literature alone. In determining whether
scientific evidence supports a causal claim for risk factors and work-
related musculoskeletal disorders, the NAS/NRC steering committee
considered the following five criteria:
Temporal ordering requires that the cause be present
before the effect is observed.
Cause and effect covary. For example, when no force is
applied to a tendon, it remains in a relaxed state; in the presence of
the cause (a force), the tendon responds.
Absence of other plausible explanations for the observed
effect. Adequate controlling of confounding factors by the design of
the experiment or observation makes other explanations for the observed
effect less likely.
Temporal contiguity, amplifies the first (temporal
ordering). To the extent that the effect follows the cause closely in
time, the plausibility that other factors are operative is reduced.
Congruity between the cause and effect, that is the size
of the cause is related to the size or magnitude of the effect.
In its report, the NRC noted that in addressing complex research
questions, such as relationships between risk factors and work-related
musculoskeletal disorders, single studies rarely, if ever, provide
conclusiveness of a causal relationship. Replication and synthesis of
evidence across studies, preferably with studies that use a variety of
methods (each with different strengths and weaknesses) strengthens
causal associations. In performing such synthesis, studies that most
completely satisfy the five criteria specified above should be given
greatest weight. Inferential strength is gained by examining the
evidence from a variety of theoretical perspectives, as well as a
variety of research methods. A major strength of the NRC/NAS review is
that it takes this broad approach toward evaluating the relevant
scientific evidence.
In evaluating the epidemiologic literature and NIOSH's review of
that literature, the NRC/NAS steering committee identified the
following limitations in the epidemiologic evidence:
Temporal contiguity between the stressors and onset of
effects, as well as amelioration after reduction of stressors, could
not always be established, nor could the clinical course of the
observed effects;
Methods used for the assessment of exposures and health
outcomes vary, rendering the task or merging and combining evidence
more challenging than in some other areas of occupational risk
assessment;
Lack of baseline prevalence and incidence data for the
general population.
Despite these limitations, the steering committee reached the
following conclusions regarding the epidemiologic evidence:
Restricting our focus to those studies involving the
highest levels of exposure to biomechanical stressor of the upper
extremity, neck, and back and those with the sharpest contrast in
exposure among the study groups, the positive relationship between
the occurrence of musculoskeletal disorders and the conduct of work
is clear. * * * (T)hose associations identified by the NIOSH review
(NIOSH, 1997; Ex 26-1) as having strong evidence are well supported
by competent research on heavily exposed populations.
There is compelling evidence from numerous studies that
as the amount of biomechanical stress is reduced, the prevalence of
musculoskeletal disorders at the affected body region is likewise
reduced. This evidence provides further support for the relationship
between these work activities and the occurrence of musculoskeletal
disorders.
Evidence of a role for biomechanical stress in the
occurrence of musculoskeletal disorders among populations exposed to
low levels of biomechanical stressors remains less definitive,
though there are some high-quality studies suggesting causal
associations that should serve as the basis for further
investigation. In cases of low levels of biomechanical stress, the
possible contribution of other factors to musculoskeletal disorders
is important to consider. The report then addresses other factors,
including individual factors (e.g., age, prior medical conditions);
and organizational and social factors (e.g., job content and
demands, job control and social support).
The conclusions from the NAS/NRC report (Ex. 26-37) from the
biomechanical literature are presented (in brief) in the previous
discussion of ``force''in Section A.
In setting forth its conclusions on musculoskeletal disorders in
the workplace, NRC/NAS steering committee notes that it has:
supplemented our professional expertise with workshop presentations,
commissioned papers and other submissions, and
[[Page 68441]]
discussions with invited workshop participants.
and, as a result concluded (in summary):
There is a higher incidence of reported pain, injury,
loss of work, and disability among individuals who are employed in
occupations where there is a high level of exposure to physical
loading than for those employed in occupations with lower levels of
exposure.
There is a strong biological plausibility on the
relationship between the incidence of musculoskeletal disorders and
the causative exposure factors in high-exposure occupational
settings.
Research clearly demonstrates that specific
interventions can reduce the reported rate of musculoskeletal
disorders for workers who perform high-risk tasks.
Research can (1) provide a better understanding of the
mechanisms that underlie the established relationships between
causal factors and outcomes; (2) consider the influence of multiple
factors (mechanical, work, social, etc.) on symptoms, injury,
reporting, and disability; (3) provide more information about the
relationship between incremental change in load and incremental
biological response as a basis for defining the most efficient
interventions; (4) improve the caliber of measurements for risk
factors, outcome variables, and injury data collection systems; and
(5) provide better understanding of the clinical course of these
disorders.
The relevant scientific literature has been thoroughly and
systematically evaluated by two highly-reputable and independent
scientific bodies and their experts, who used different approaches to
evaluate the literature from different scientific disciplines (while
allowing for some overlap), using causality criteria from two related
but different frameworks. The NIOSH and NRC/NAS reviews offer two
distinct but consistent sets of conclusions that can be drawn from the
literature on work-related musculoskeletal disorders. Generally, both
reviews agree that the scientific evidence provides compelling support
for a higher risk of work-related musculoskeletal disorders and the
loss of work, and disability among individuals who are employed in
occupations where there is a high level of exposure to physical loading
(biomechanical factors), and that evidence clearly demonstrates that
specific interventions can reduce the reported rate of musculoskeletal
disorders for workers who perform high-risk tasks.
In the face of overwhelming evidence that biomechanical/physical
risk factors in the workplace cause MSDs, some critics, such as UPS
argue that there is not even one study which demonstrates that
repetitive motion causes injury (Ex. 32-241-4). When asked at the
hearing whether he agreed with this UPS position, Dr. Robert McCunney,
representing the American College of Occupational and Environmental
Medicine replied ``I find this statement incredulous'' (Tr. 7662). Dr.
McCunney then continued in his testimony to state that there is
sufficient scientific literature showing that repetitive motion
activities can lead to MSDs. According to Dr. Barbara Silverstein, of
the Washington State Department of Labor and Industries, scientific
researchers who hold to the UPS view that there is no evidence that
repetitive movements causes injury ``are in a minority'' (Tr. 17415).
Likewise, in response to the same question regarding the UPS
contention, Dr. Thomas Armstrong (University of Michigan) defended the
scientific evidence that repetitive movements can result in injury, by
replying:
There are physiological studies looking at repetitive work as it
contributes to muscle fatigue and changes in histology of muscle
tissue. There are epidemiological studies that have looked at the
relationship between various exposures to repetition and a variety
of musculoskeletal types of disorders. These studies from different
disciplines all come together and support the same conclusion.
Professional and scientific organizations supporting OSHA's
determinations regarding the scientific basis underlying the standard
include:
American Association of Occupational Health Nurses (Ex.
30-2387)
American College of Occupational and Environmental
Medicine (Ex. 30-4468, Tr. 7637-7690)
American Conference of Governmental Industrial Hygienists
(Ex. DC-386, Tr. 16291-335)
American Industrial Hygiene Association (Ex. 32-133-1, Tr.
16464-72, Tr. 16518-27)
American Nurses Association (Ex. 30-3686, Tr. 15875-95)
American Occupational Therapy Association (Ex. 30-4777,
Tr. 18095-18121)
American Public Health Association (Ex. 30-626, Tr. 17649-
17704)
American Society of Safety Engineers (Ex. 32-21-1-2; Tr.
11612)
Human Factors and Ergonomics Society (Ex. 502-472)
National Association of Orthopedic Nurses (Tr. 10578-
10588)
The American Society of Plastic and Reconstructive Surgery
(Ex. DC-46, Tr. 1534)
OSHA finds no merit to assertions that there is insufficient
science on which to base its proposal and subsequent final rule.
Rather, the Agency finds that the body of scientific evidence on which
OSHA based this rule is vast and conclusive. This position was
supported by many witnesses and multiple pages of hearing testimony,
and added to the substantial base of scientific literature that OSHA
relied on for the publication of it's proposal. And, although there
have been critics to OSHA's actions, they are in fact, in the vast
minority. The science overwhelmingly supports reducing biomechanical
risk factors in the workplace as an effective approach to reducing
work-related musculoskeletal disorders.
When asked ``whether ACOEM believes that detection and elimination
of these ergonomic risk factors at work can result in a reduction in
the number of these disorders'' during the hearing, Dr. McCunney
replied ``Very much so'' (Tr. 7663).
The following parts of this section discuss the evidence for the
work-relatedness of MSDs. Tables V-1 through V-8 summarize some key
aspects of the epidemiological studies that investigate MSDs, such as
the occupations examined, the biomechanical risk factors they were
exposed to, whether exposures were directly observed or measured during
the study, and whether the health outcomes were verified by trained
medical personnel during physical examination. The last column provides
a quantitative (if available) risk measure or range of risk measures
reported in each study that best captures the strength of the
association between the studied biomechanical risk factor(s) and health
outcome. Study entries with a single odds (or prevalence) ratio
examined the relative risk between an exposed group of workers and
unexposed referent population. For most studies, the risk values and
confidence intervals were obtained from tables found in the 1997 NIOSH
review (Ex. 26-1). For the additional studies not reviewed by NIOSH,
OSHA obtained risk values from the material submitted in the docket.
Many studies reported risk ratios for multiple exposed groups and/
or several indicators of exposure to biomechanical risk factors. In
these cases, the range of reported risk measures were provided in the
summary tables. OSHA did not include in this range; (1) risks ratios
(high or low) that were inherently unstable because they were based on
very low numbers of cases; (2) risk ratios that did not reflect
differences in biomechanical risk factors; and (3) risk ratios in which
the variation in exposure between groups were so small that a
difference in MSD prevalence
[[Page 68442]]
would have been difficult to detect. The 95 percent confidence interval
for the upper end of the risk range were also recorded on the tables.
Some studies on the tables did not report odds (or prevalence)
ratios, even though they may have established a statistically
significant association between biomechanical risk factor and health
outcome. Often, the association was expressed as a regression analysis
between a particular biomechanical measurement and number of MSD cases.
Sometimes, the study did not provide a risk measure but simply reported
the MSD prevalence of different groups of exposed workers. These study
entries were designated with a NR (risk ratio not reported).
C. Disorders of the Neck and Shoulder
MSDs of the neck and shoulder that have been documented in the
scientific literature include the clinically well-defined disorders,
such as tendinitis, and the less clinically well-defined soft tissues
disorders, such as tension-neck syndrome (Gerr 1991, Ex. 26-1208; Moore
1992, Ex. 26-984). MSDs of the neck and shoulder often involve tendons,
muscles, and bursa; nerves and blood vessels may also be affected.
Because of the simultaneous involvement of several regional structures
in neck and shoulder MSDs, there may be positive signs and/or symptoms
in more than one structure. For example, strong abduction or extension
of the upper arm, as well as awkward postures of the neck, can compress
parts of the brachioplexus under the scalene muscles and other
anatomical structures. This compression can result in nerve and/or
blood vessel damage or in eventual damage to the tissues served by
these nerves and vessels.
Neck and Upper Back
In this section, OSHA summarizes the evidence for an increased risk
for musculoskeletal disorders of the neck and upper back associated
with exposure to biomechanical risk factors in the workplace. This
region (neck and upper back) includes the cervical and thoracic spine
(spine above the lumbar or low back) and supporting structures and
tissues. The scientific literature frequently refers to this region as
``Neck and Neck/Shoulder,'' or as ``Neck and Shoulder'' or as ``Neck
and Upper Back.'' With respect to the epidemiologic literature, the
studies NIOSH referred to in it's ``Neck and Neck/Shoulder'' section
are included in this section. A summary of the evidence regarding the
shoulder only is reviewed in the separate section following this one.
For greater detail on the scientific evidence summarized here see 64 FR
65865-65926).
The lifetime prevalence of neck pain is estimated at 40% to 50%,
with a 1-year prevalence of about 20% (Takala et al.1982, Ex. 26-1169).
Using a definition of 2 weeks of neck pain, the prevalence among men
and women aged 25 to 74 years in the NHANES Survey II (1976 to 1980)
was 8.2% (Praemer, Furner, and Rice 1992, Ex. 26-869). Chronic neck
pain is estimated to be present in up to 9% to 10% of males and 12% to
14% of females (Makela et al.1991, Ex. 26-980; Revel et al.1994, Ex.
26-195). Individuals in the 4th to 6th decades of life have the
greatest incidence of neck disorders (Makela et al.1991, Ex. 26-980;
Praemer, Furner, and Rice 1992, Ex. 26-869).
What is known about the course of neck pain? It is estimated that
90% of patients with acute neck pain are improved within 2 months
(Borenstein, Wiesel, and Boden 1996, Ex. 26-1394). The Quebec Spinal
Study (1987, Ex. 26-494) series of individuals with work-related spinal
disorders suggests that 74% recover by 7 weeks. A 10-year outcome study
of patients with neck pain revealed that 79% had less pain and 43% were
pain-free. However, 32% still experienced moderate or severe pain (Gore
et al.1987, Ex. 26-127). With regard to work-related MSDs, some
intervention studies have suggested that workplace modifications may
decrease both symptoms of neck pain and/or muscle activity as recorded
by EMG (Aaras 1994a, Ex. 26-892; Aaras et al.1998, Ex. 26-597; Schuldt
et al.1987, Ex. 26-670).
The extent to which neck pain occurs in or affects workers depends
to a great extent on the terms used to define the pain, in terms of
intensity and duration, and on the methods used in determining the
presence or occurrence (self-report, interview, or physical
examination). Point prevalence of neck pain in a general U.S.
population has been reported at 10%, matching point prevalence reports
of workers in an aeroengineering factory and exceeding a 4% prevalence
reported in a group of textile workers (Palmer et al.1998, Ex. 26-1529
). Other estimates found in the literature include 68% for female and
47% for male Swedish industrial workers performing unskilled tasks (3-
month prevalence of MSDs in the neck and in the thoracic
back)(Bjorksten et al.1996, Ex. 26-604). One-year prevalence of neck
pain or neck and upper-back pain was 16% in a group of electricians,
excluding neck pain associated with traumatic injury, and 38% with a
less restrictive definition (Hunting, et al.199, Ex. 26-1273); 26% and
18%, in the Danish wood and furniture industry respectively
(Christensen, Pedersen, and Sjogaard 1995, Ex. 26-95). Prevalence of
regular discomfort in the posterior neck region was 6.3%, and 9.1% in
the upper-back region, in a group of chicken-processing workers.
However, the lifetime prevalence was 36%, the point prevalence was 18%,
and 9% had sought medical treatment for discomfort (Buckle 1987, Ex.
26-938).
Many studies of neck pain have focused on employees working in
health care. Milerad and Ekenvall (1990, Ex. 26-1291) reported cervical
symptom prevalence of 45% of male dentists and 63% of female dentists,
rates that were 2.6 and 2 times those of male and female pharmacists,
respectively. Twelve-month prevalence of self-reported neck pain was
63.1% in a group of medical secretaries and hospital office personnel
(Linton and Kamwendo 1989, Ex. 26-978).
With regard to work-related cervical spine disorders, the Quebec
Spinal Study (1987, Ex. 26-494) observed an annual incidence of over
0.1%. However, Bjorksten et al.(1996, Ex. 26-604) reported a 68%, 3-
month prevalence for neck pain in industrial workers performing
unskilled tasks, more than double the rate in the general population.
Certain jobs appear to have greater associations with neck pain than
others, with the lifetime prevalence of neck and shoulder symptoms
reaching 81% in machine operators, 73% in carpenters, and 57% in office
workers (Tola et al.1988, Ex. 26-1018). It must be understood that
there may be an underestimation of work-relatedness of neck pain since
the onset of pain may, at times, be delayed and the work relation
uncertain.
Tension neck syndrome is a myofascial (muscle pain) localized in
the shoulder and neck region (Hagberg 1984; Ex. 26-1271). Also called
scapulocostal syndrome (Fine and Silverstein 1998; Ex. 38-444), these
syndromes are often characterized by diffuse tenderness over the
muscle, rather than the tendon origin, and activity limitation. The
pathophysiology is unknown; however, a number of mechanism have been
proposed, including inflammation. Two types of muscle activity may be
important in work-related disorders: low-force, prolonged muscle
contractions (e.g., in office workers moderate neck flexion while
working on a visual display terminal (VDT) for many hours without rest
breaks); and infrequent or frequent high-force muscle contractions
(intermittent use of heavy tools) in
[[Page 68443]]
overhead work). Sustained static contractions can lead to increases in
intramuscular pressure, which in turn may impair blood flow to cells
within the muscle (Hagberg, 1984; Ex. 26-1271).
Motor nerve control of the working muscle may be important in
sustained static contractions since even if the relative load on the
muscle as a whole is low, the active part of the muscle may be working
close to it's maximal capacity. Thus, small areas of large muscles such
as the trapezius may have disturbances in microcirculation that might
contribute or cause the development of muscle damage (red ragged
fibers), reduce strength, higher levels of fatigue, sensitization of
pain receptors in the muscle, and pain at rest (Armstrong, Buckle and
Fine 1993, as cited in Fine and Silverstein 1998, Ex. 38-444). High
levels of tension (strong contractions) can lead to muscle fiber Z-line
rupture, muscle pain, and large, delayed increases in serum creatine
kinase. These changes are reversible and can be completely repaired,
often leading the muscle to be stronger. It is hypothesized that if
damage occurs daily due to work activity, the muscle may not be able to
repair the damage as fast as it occurs, leading to chronic muscle
damage or dysfunction. The mechanism of this damage at the cellular
level is not understood (Armstrong, Buckle and Fine, 1993 as cited in
Fine and Silverstein 1998, Ex. 38-444).
Hagberg (1984, Ex. 26-1271; and Hagberg and Wegman 1987, as cited
in Magnusson and Pope Ex. 38-450) described three possible
pathophysiological mechanisms for occupational muscle-related
disorders, such as tension neck syndrome. The first is mechanical
failure, due to temporary high local stress involving eccentric
contractions on the shoulders, such as in workers unaccustomed to the
work task. The second is local decreased blood flow (ischemia), as seen
in assembly workers whose tasks involved dynamic, frequent contractions
above 10 to 20% of the maximum voluntary contraction and few rest
breaks. Both a reduction in blood flow and pathologic changes were
found to be correlated with myalgia (muscle pain) and ragged red fibers
in 17 patients doing repetitive assembly work (Larsson et al.1990, Ex.
26-1141).
The third pathophysiologic mechanism for muscle pain (Hagberg 1984,
Ex. 26-1271) energy metabolism disturbance, occurs when energy demand
exceeds production. Long-term static contractions of the muscles result
in the prolonged recruitment of limited numbers of motor units, and can
deplete available energy, producing eventual fatigue and injury (Lieber
and Friden 1994, Ex. 26-559). Higher subjective levels of fatigue as
well as electrophysiological evidence of fatigue are more common in
large muscle groups, such as the neck and shoulder muscles, when
activities are static and repetitive rather than dynamic (Sjogaard
1988, Ex. 26-830).
Pain arising from cervical spine skeletal structures may
potentially originate from many locations, since sensory nerve
innervation is present in ligaments, joint capsules, the anterior and
posterior longitudinal ligaments, the outer third of the annulus
fibrosus, and the vertebral body (Bogduk 1982, Ex. 26-1479; Bogduk et
al.1988, Ex. 26-514; Hirsch, Inglemark, and Miller 1963, Ex. 26-471).
The periosteum of the cervical vertebral body may be a source of pain,
although some slowly progressive lesions may destroy a significant
amount of bony tissue before they are recognized (Borenstein, Wiesel,
and Boden 1996, Ex. 26-1394). The spinal nerve roots are the source of
pain when there is compression, ischemia, and inflammatory or chemical
mediators that stimulate nociceptors.
Cervical spondylosis refers to degenerative changes in the cervical
spine that are apparent on radiological examination (Hagberg and Wegman
1987, Ex. 26-32). The pathogenesis of cervical spine degenerative
disease has similarities to many other joint structures, although there
are important differences. The cervical spine has a great deal more
movement, achieved via gliding and sliding on adjacent structures, than
the remainder of the spine. And not being subject to repetitive and
impulsive loading, cervical spinal segments do not require the strength
and stability of the lumbar-sacral spine. However, these zygoapophyseal
joints in the cervical spine have fibrocartilagenous, meniscus-like
structures that are capable of responding with proliferative changes
(Bland 1994, Ex. 26-416 ). As with other joints, aging, repetitive
motion, and some loading result in fissuring of the hyaline cartilage
surfaces. Gradually, the hyaline cartilage develops deeper and downward
fissuring, larger erosions, and general thinning. In the cervical
spine, the chondrocytes proliferate in areas of fibrillation or loosely
textured matrix (Bland 1994, Ex. 26-416). And though the matrix may
demonstrate some attempts at repair, the repair is generally
disorderly. Subchondral bone increases in density, followed by
microfracturing and callus formation. New bone, called osteophytes,
appear at the margins of the articular cartilage, and may protrude into
the joint space or neuroforamen. If large enough, this may cause nerve
compression. Posterior spondylotic bars, especially if combined with
hypertrophy of the ligamentum flavum, have the potential to compress
the spinal cord, causing symptoms of cervical myelopathy. Anatomically,
the C4 to C5, C5 to C6, and C6 to C7 intervertebral disc spaces are
most commonly affected by osteoarthritis and degenerative disc disease.
Thoracic outlet syndrome (TOS) is defined as a ``neurovascular
impingement syndrome at different anatomical levels where the brachial
plexus and subclavian vessels may be entrapped as they pass through, en
route from the cervical spine to the arm.'' (Hagberg et al.1995, Ex.
26-432). The syndrome involves compression of the subclavian artery and
the lower trunk of the brachial plexus, at one or more locations
between the neck and the axilla. Symptoms are experienced in the upper
extremity. Cervical syndrome is defined as ``compressions of the nerve
root by a herniated disc or a narrowed intervertebral foramen''
(Hagberg et al.1995, Ex. 26-432).
Epidemiological Evidence
Several muscles act upon the upper spine and shoulder girdle
together; Scandanavian studies have often combined neck and shoulder
MSDs. Neck pain and MSDs will be discussed here. Those studies that
evaluated neck and shoulder pain and MSDs together will also be
included. Studies that exclusively evaluate pain and MSDs of the
shoulder will be discussed in a subsequent section. Studies that have
evaluated objective findings and/or met diagnostic criteria for
specific disorders have been given greater weight in this analysis.
There have been several reviews that associate neck disorders work
factors, such as repetition, force, static loading, neck posture, and
heavy work (NIOSH 1997, Ex. 26-1; Grieco, et al.1998, Ex. 26-627;
Hagberg et al.1995, Ex. 26-432; Hales and Bernard 1996, Ex. 26-896;
Viikari-Juntura 1997, Ex. 26-905; Hagberg and Wegman 1987, Ex. 26-32).
The majority of neck disorders involve soft tissues (muscle and
ligament strains and sprains). Outcomes studied and reported are often
non-specific, for example, neck pain or/or stiffness. Some studies
relied on combination of symptoms and physical exam confirming
tenderness in neck muscles and tendons upon palpitation and/or
localized pain during neck movement. Many others simply relied on self-
[[Page 68444]]
reported symptoms on a questionnaire. While duration of symptoms and
case definitions were not always completely consistent, all studies
attempted to exclude pain and/or discomfort that was transient or less
than significant intensity.
In a few epidemiological studies, objective exposure measurement
that pertained to the neck region, such as work load assessments,
electromyography, neck angle measurement, was obtained. However in most
studies, exposure assessments were based on job titles or self-reports.
In some investigations the primary interest and measurement strategy
was focused on hand/wrist region, even though neck disorders were
studied as one of the outcomes. Hand/wrist exposures will not
necessarily reflect the biomechanical status of the neck, and,
therefore these studies have potential for considerable exposure
misclassification are given less weight.
Bernard (1997, Ex. 26-1) and NIOSH reviewed epidemiological studies
for evidence of work-relatedness of neck and neck/shoulder
musculoskeletal disorders. In the process of identifying papers for
this review, Bernard (1997, Ex. 26-1) first considered the strength of
each study based on whether it provided clear definitions of exposed
and reference populations and clear definitions of outcomes, as well
whether it evaluated exposures in such a way as to classify them with
regard to force, repetition, posture, or vibration. Papers that met
these standards were then evaluated based on four criteria: a 70% or
better response rate in order to limit response bias, health outcome
defined by symptoms and physical examination (PE)(1), investigators
blinded where appropriate (exposure or health status), and the neck as
a focus of the evaluation. Only one of the studies that focused on the
neck and two that focused on the neck/shoulder region met all four
criteria. The likelihood of bias in each study was examined. Finally,
studies were summarized with respect to strength of association,
demonstration of temporal association, consistency of association among
studies, and exposure-response relationship.
The NIOSH review identified 46 epidemiological studies (1976 to
1995) reporting on the neck and 23 reporting on the neck/shoulder
region. Of these studies, 38 were cross-sectional, 2 were case-control,
and 6 were prospective studies. Table V-1 summarizes some key aspects
of these investigations, such as the occupations examined, the
biomechanical risk factors the workers were exposed to, whether
exposures were directly observed or measured during the study, and
whether the health outcomes were verified by trained medical personnel
during physical examination. Thirteen of the studies directly measured
or observed a combination of repeated arm/shoulder movements, strenuous
work that generates loads to the neck/shoulder muscles, and extreme
static postures. The eleven studies also used physical examination by a
health professional to define workers with neck disorders. OSHA regards
these investigations as more reliable than those in which direct
exposure was not observed or in which neck injuries are self-reported.
Twelve of the thirteen studies reported a statistically significant
association between these disorders and physical work factors (force,
repetitive motion, awkward posture).
Table V-1.--Summary of Epidemiology Studies Examining Neck and Upper Back Musculoskeletal Disorders
--------------------------------------------------------------------------------------------------------------------------------------------------------
Study Job type studies Physical factors Exposure basis Diagnosis Risk Measure (95% CI) \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hunting (1981) Ex. 26-1276......... VDT operation........ R/P observation.......... physical exam........ OR=9.9 *
body posture......... (3.7-26.9)
Veiersted (1994) Ex. 26-1366....... chocolate manufacture F/R?/P EMG.................. physical exam........ OR=6.7-7.2 *
(2.1-25.3)
Ohlsson (1995) Ex. 26-868.......... assembly line........ R/P neck flexion......... physical exam........ OR=3.6 *
cycle time........... (1.5-8.8)
Bergqvist (1995) Ex. 26-1195....... VDT operators........ R/P observation.......... physical exam........ OR=3.6-4.4 *
(1.1-17.6)
Bergvist (1995) Ex. 26-1196........ VDT operators........ R/P observation.......... physical exam........ OR=6.9 *
(1.1-42.1)
Onishi (1976) Ex. 26-1222.......... film rolling......... F?/R/P observation.......... physical exam........ OR=3.8 *
EMG.................. (2.1-6.6)
Norander (1999) Ex. 38-408......... fish processing...... R/P observation.......... physical exam........ OR=3.0 *
cycle time........... (1.5-5.9)
Kukkonen (1983) Ex. 26-1138........ data entry........... R?/P posture.............. physical exam........ OR=2.3 *
observation.......... (1.1-4.6)
Bjelle (1981) Ex. 26-1519.......... industrial plant..... F/R/P flexion.............. physical exam........ NR *
EMG..................
Jonsson (1988) Ex. 26-969; Kilbom electronics F/R/P flexor MVC........... physical exam........ NR *
(1986) Ex. 500-41-75. manufacture. flexion..............
Dimberg (1989) Ex. 26-1211......... automotive........... F/R/P observation.......... physical exam........ NR*
(p0.1)
Sakakibara (1995) Ex. 26-800....... fruit bagging........ F?/R?/P observation.......... physical exam........ OR=1.5
arm elevation........ (1.0-2.3)
Rosecrance (1994) Ex. 38-203....... newspaper work....... F?/P/R questionnaire........ symptoms only........ OR=29 *
Andersen (1993) Ex. 26-1502........ sewing machine....... F/R/P? job titles........... physical exam........ OR=6.8 *
(1.6-28.5)
Baron (1991) Ex. 26-697............ grocery checking..... F/R/P job titles........... physical exam........ OR=2.0
(0.6-2.7)
Bernard (1994) Ex. 26-842.......... newspaper publishing. R?/P observation.......... symptoms only........ OR=1.4 *
(1.0-1.8)
Blader (1991) Ex. 26-1215.......... sewing machine....... R/P questionnaire........ physical exam........ NR *
Hales (1989) Ex. 2-3-pp............ poultry processing... F/R job title............ physical exam........ OR=1.6
(0.4-3.2)
Hales (1994) Ex. 26-131............ telecommunication.... R?/P questionnaire........ physical exam........ OR=3.8*
(1.5-9.4)
[[Page 68445]]
Hunting (1994) Ex. 26-1273......... electrician.......... V/F/R/P questionnaire........ symptoms only........ OR=1.6
(NR)
Kamwendo (1991) Ex. 26-1384........ medical secretary.... R/P questionnaire........ symptoms only........ OR=1.6*
(1.0-2.7)
Kiken (1990) Ex. 26-430............ poultry processing... F/R job title............ physical exam........ OR=1.3
(0.2-11)
Knave (1985) Ex. 26-753............ VDT operation........ R/P questionnaire........ symptoms only........ OR=1.6
(0.4-3.2)
Kuorinka (1979) Ex. 26-639......... scissor production... R/P job title............ physical exam........ OR=4.1*
(2.3-7.5)
Luopajarvi (1979) Ex. 26-56........ food production...... F/R/P? job title............ physical exam........ OR=1.6
(0.9-2.7)
Schibye (1995) Ex. 26-1463......... sewing machine....... F?/R/P? questionnaire........ symptoms only........ OR=3.3*
(1.4-7.7)
Liss (1995) Ex. 26-55............. dental hygienist..... F/R/P? questionnaire........ symptoms only........ OR=1.7*
(1.1-2.6)
Ohlsson (1989) Ex. 26-1290........ auto assembly........ F/R/P? job title............ symptoms only........ OR=1.9
(0.9-3.7)
Andersen (1993) Ex. 26-1451....... sewing machine....... F/R/P? job titles........... symptoms only........ OR=3.2-4.9*
(2.0-12.8)
Eckberg (1995) Ex. 26-1193........ residents............ F?/R/P? questionnaire........ symptoms only........ OR=1.2*
(1.0-1.3)
Eckberg (1994) Ex. 26-1238........ case-control......... F?/R/P questionnaire........ symptoms only........ OR=3.6-15.6*
(3.2-113)
Milerad (1990) Ex. 26-1291........ dentist.............. R/P questionnaire........ symptoms only........ OR=2.1*
(1.2-3.1)
Punnett (1991) Ex. 26-39.......... meat processing...... F/R/P? observation.......... symptoms only........ OR=0.9-1.8
(1.0-3.2)
Rossignol (1987) Ex. 26-804....... computer operation... R/P questionnaire........ symptoms only........ OR=1.8-4.6*
(1.7-13.2)
Viikari-Juntura (1994) Ex. 26-873. machine operation.... F/R?/P/V observation.......... symptoms only........ OR=3.0-4.2*
(2.0-9.0)
Wells (1983) Ex. 26-729............ letter carrier....... F/R?/P job title............ symptoms only........ OR=2.6 *
(1.1-6.2)
Aaras (1994) Ex. 26-892............ telephone assembly... F/R?/P EMG.................. symptoms only........ NR *
muscle load..........
Ferguson (1976) Cited in Ex. 26-1.. telephone interview.. R?/P posture measures..... symptoms only........ NR
Maeda (1982) Ex. 26-1224........... machine operators.... F?/R?/P? questionnaire........ symptoms only........ NR *
Linton (1989) Ex. 26-729........... medical secretary.... R?/P? questionnaire........ symptoms only........ NR
Linton (1990) Ex. 26-977........... multiple industries.. F?/R?/P questionnaire........ symptoms only........ OR=3.5
(2.7-4.5)
Sakakibara (1987) Ex. 26-1199...... fruit bagging........ F?/R/P neck/shoulder flexion symptoms only........ OR=1.6
(0.4-3.2)
Welch (1995) Ex. 26-1268........... sheet metal F?/R/P questionnaire........ symptoms only........ OR=7.5
processing. (0.8-68)
Yu (1996) Ex. 26-696............... VDT operation........ R?/P questionnaire........ symptoms only........ OR=29
(2.8-291.8)
Holmstrom (1992) Ex. 26-36......... construction......... F?/R?/P questionnaire........ symptoms only........ OR=2.0 *
(1.4-2.7)
Ryan (1998) Cited in Ex. 26-1...... data processing...... R?/P shoulder flexion..... symptoms only........ NR*
Ohara (1976) Cited in Ex. 26-1..... cash register........ F?/R?/P? job title............ physical exam........ NR
Tola (1988) Ex. 26-1018............ machine operation.... F?/R?/P job title............ symptoms only........ OR=1.8 *
(1.5-2.2)
Vihma (1982) Ex. 26-789............ sewing machine....... R/P observation.......... symptoms only........ PRR=1.6 *
cycle time........... (1.1-2.3)
Viikari-Juntura (2000) Ex. 500-41- forest industry...... P/R? questionnaire........ symptoms only........ OR=1.4
50.
Botha (1998) Ex. 500-212-10........ nurses............... P/F observation.......... symptoms only........ NR *
Bjork Csten (1996) Ex. 26-604...... metal working........ R/P questionnaire........ symptoms only........ NR
Ignatius (1993) Ex. 26-1389........ typists.............. F/R?/P questionnaire........ symptoms only........ OR=3.4 *
Slov (1996) Ex. 26-674............. sales................ P questionnaire........ symptoms only........ OR=2.8 *
(1.4-5.59)
--------------------------------------------------------------------------------------------------------------------------------------------------------
F=forceful exertions; R=repetitive motion; P=awkward posture; ?=presence of risk factor unclear
OR=odds ratio; PRR=prevalence rate ratio, NR=not reported;
*=p0.05
\1\ 95% confidence interval expressed for the upper end of the risk measure range
[[Page 68446]]
The odds ratios determined from the studies ranged from 1.1 to 9.9.
Several studies deserve special mention. Ohlsson et al.(1995, Ex. 26-
868) compared 82 female industrial workers exposed to short-cycle tasks
(less than 30 seconds) to 64 referents with no exposure to repetitive
work. The OR for tension neck syndrome was 3.6 (95% CI: 1.5-8.8).
The NIOSH authors concluded that there was ``reasonable evidence''
for an association between highly repetitive work and neck/shoulder
MSDs, where repetitiveness was most often defined in terms of hand
activity. They also determined that there was ``reasonable evidence''
for an association between forceful exertion and neck/shoulder MSDs,
where forceful work was conducted by the arms. They concluded there was
``strong evidence'' for an association between static loads and neck/
shoulder MSDs, where ``static load'' referred to a static load of long
duration, high intensity, or extreme amplitude. In many of the
situations under study, workers were exposed to more than one of these
physical risk factors during the course of their jobs. The NIOSH review
found insufficient evidence of an association between vibration and
neck disorders.
In an earlier review, Hales and Bernard (1996, Ex. 26-896)
concluded that neck disorders were associated with work involving
repetitive motions, forceful repetitive work, and constrained or static
postures, based on consistency of association across several studies.
They noted inconsistent findings regarding neck disorder and work pace,
which, they suggested, may be due to the many ways work pace can be
quantified. Hales and Bernard also mentioned a consistent association
between wearing bifocals, awkward neck postures, and neck disorders.
Hagberg et al. (1995, Ex. 26-432) reviewed epidemiological studies
for evidence of work-relatedness of selected musculoskeletal disorders
of the neck: TOS (neurogenic form), cervical syndrome, and tension neck
syndrome. In compiling a list of valid papers for their review, the
researchers considered the strength of each study based on minimization
of bias (selection bias, information or misclassification bias,
confounding or effect modification bias) and study power. Studies that
met their validity criteria were then reviewed for causality (strength
of association, demonstration of temporal association, consistency of
association among studies, predictive power of exposure factors, and
plausibility.
Hagberg et al. found six cross-sectional studies of TOS (published
between 1979 and 1991) that met their inclusion criteria. From those
studies they found the strength of association between work and TOS to
be generally weak, based on low odds ratios (ORs). Since all studies
were cross-sectional in design, temporal associations could not be
confirmed. There seemed to be a consistent association between
repetitive work and TOS across the studies. One study demonstrated a
dose-response relationship between vibration and TOS. The authors also
noted an association between TOS and age. Hagberg et al. (1995, Ex. 26-
432) concluded that the studies demonstrated the existence of a
consistent association between repetitive arm movements, manual work,
and TOS.
In their review, Hagberg et al.(1995, Ex. 26-432) found twelve
cross-sectional studies and one laboratory study of tension neck
syndrome (published between 1976 and 1988) that met their inclusion
criteria. From those studies, Hagberg et al.(1995, Ex. 26-432) found
the strength of association between work and tension neck syndrome to
be moderate, based on ORs from 3 to 7. There seemed to be a consistent
association between work with VDTs and tension neck syndrome across
several studies, including a determination of an OR for tension neck
syndrome of 2.0 in keyboard operators (Hagberg and Wegman 1987, Ex. 26-
32). There also seemed to be consistent associations between tension
neck syndrome and repetitive work and static head and arm postures. The
authors also noted that tension neck syndrome was found more commonly
in women, but that finding may have been confounded by differences in
work. Hagberg et al.(1995, Ex. 26-432) concluded that the studies
demonstrated the existence of a consistent association between
repetitive work and tension neck syndrome caused by constrained head
and arm postures. They also noted that tension neck syndrome had a high
prevalence in both work and reference groups.
Three cross-sectional studies of cervical radiculopathy (published
between 1979 and 1983) met the criteria of Hagberg et al.They observed
that all studies showed a low prevalence for cervical radiculopathy.
Low numbers meant wide confidence intervals, which made results
difficult to interpret. They concluded that more directed research
needed to be conducted in this area.
In a review of the epidemiological evidence for three neck-related
MSDs, the contributors to Kourinka and Forcier (1995 Ex. 26-432) report
consistent associations between exposures to static head and arm
postures and outcomes of tension neck syndrome. They did not find
convincing evidence of a connection between repetition and cervical
radiculopathy.
A recent review of epidemiological studies by Grieco et al.(1998,
Ex. 26-627) concluded that cervical radiculopathy had not been shown to
be associated with data entry work, dockers' work, or food production
assembly line work. In contrast, tension neck syndrome was linked to
static postures and static loads in several studies on populations of
VDT workers, typists, and sewing machine operators. Study selection
criteria were not discussed in that review.
Several individual studies of workers performing heavy work
(including meat carriers and miners) found increased ORs (most adjusted
for age) for cervical spondylosis, as did one study of dentists.
Viikari-Juntura (1997, Ex. 26-905) reviewed both epidemiological and
experimental studies focused on the neck (among other regions). The
author mentioned studies that showed associations between degenerative
changes or neck pain and heavy work, repeated impact loading, or static
work, whereas the OR for cervical spondylosis in cotton workers was
0.66 (protective). The relationships between work factors and cervical
spine arthritis have not been clarified due to (1) few studies of this
subject, (2) a lack of universal acceptance for the criteria (e.g.,
symptoms, signs, imaging) used to make this diagnosis, and (3) cervical
spine degenerative changes are common.
Four additional epidemiological studies that address physical work
factors and neck and neck/shoulder disorders were submitted into the
OSHA docket following publication of the proposal and have been added
to Table V-1 (Nordander et. al. 1999, Ex. 38-408; Viikari-Juntura 2000,
Ex. 500-41-50; Botha and Bridger 1998, Ex. 500-121-10; Rosecrance et al
1994, Ex. 38-203). OSHA found a few additional studies identified in
the NIOSH epidemiological review for other MSDs that also addressed
neck and neck/shoulder and are also included in Table V-1 (Dimberg
1989, Ex. 26-1211; Ignatious 1993, Ex. 26-1389; Skov 1996, Ex. 26-674).
Two other submitted studies contained some serious methodological flaws
and were not included in the table (Leclerc et al., 1999, 500-118-2;
Erikson et al., 1999, 500-118-2).
Nordander et al.1999 (Ex. 38-408) reported on a cross sectional
study of 13 fish processing plants, examining multiple body sites,
including the neck and shoulder. Ninety one male and 165
[[Page 68447]]
female fish industry workers were compared to men and women with more
varied work. The work was partly paid by the work done--piece work.
Health outcome was based on questionnaire and physical examination.
Exposure was assessed by questionnaire, videotaping of jobs, and the
observational method using AET (Arbeitwissenschaftliche
Erbehungverfahren zur Tatigkeitsanalyse) along with the NIOSH lifting
equation. Each work task classified according to three factors: weight
of the materials handled (1, 15, 510, 10-25, >25 kg.), cycle time (5,
5-10, 10-60, >60); and degree of constrained neck postures (low, high,
very high). Neck and shoulder diagnoses among the fish processors was
found to be significantly elevated compared to the referents (OR=3.5;
95% CI 2.3-5.3). There was significantly increased prevalence of
shoulder tendinitis found among women fish processors (OR from 3.4 to
4.65) compared to referents. No significant effects were found due to
age, leisure time and smoking assessed by logistic regression. Job
analysis found that several tasks were repetitive, performed in
constrained work postures, with fast and continuous wrist and hand
movements, mostly with flexed neck, arms raised and lowered
intermittently. Because it involved a direct assessment of exposure and
verification of neck injury by a health professional, OSHA views the
study to be among the more reliable investigations.
Viikari-Juntura et al.2000 (Ex. 502-11) recently published findings
on a longitudinal study of neck pain among a cohort of 5180 workers in
a large forest industry enterprise. Participation rate was only 43% of
the originally selected cohort of 7000. Nonrespondents were also
followed up--there was no difference with regard to potential
predictors except reporting 1.5 times difficulties in coming 5 years
due to musculoskeletal health. Four repeated questionnaires were used
focusing on ``radiating neck pain,'' categorized as healthy (0-7 days),
mild pain (8-30 days), and severe pain (>30 days). Validated exposure
assessment questionnaires and psychosocial questionnaires were used.
There were several variables related to physical strenuousness, awkward
postures, repetitive movements, and stress. Results found a
statistically significant dose-response relationship for neck pain and
increasing number of hours working with the hands above the shoulder.
The risk of neck pain also increased with increasing amounts of
twisting movements, but for the combination of twisting of the trunk
and stress, neck pain decreased with increasing amounts of stress.
Rosecrance (1994, Ex 38-457) conducted a cross-sectional study of
906 office and production workers from three medium sized newspaper
facilities to determine the level of symptomatic workers and to compare
the office and production workers. A participation rate of 72% was
reported. A physical exam was given to 105 participants. Exposure was
assessed by a self-reported job factor survey. The results found that
workers who reported repetitive tasks had an odds ratio of 29 (CI not
reported, p=0.01) of missing work due to neck symptoms compared to
workers who did not report repetitive tasks. Production workers
reported more job risk factors compared to office workers. Neck
symptoms were the most common symptom among production workers.
Faucett and Rempel, 1994 (Ex 38-67) carried out a cross-sectional
study of 150 video display terminal (VDT) operators from large
metropolitan newspaper. Participation rate was low at 56%, however,
non-respondents had no difference in age, duration of employment,
gender, job title, or VDT training. A questionnaire-derived health
outcome using a body diagram was employed. Observational exposure
assessment was performed on 70 VDT workstations, completed by trained
independent observers working in pairs evaluating work posture, wrist,
knee and leg contact with workstation, display and seat height, angle
measures of wrist, elbow, shoulder, head, trunk at the hip and thigh.
Results found that 28% met symptom criteria for MSDs of the upper torso
and extremities. Risk of having a MSD increased with a greater number
of daily hours of VDT use. After controlling for the ergonomic factors,
less decision latitude on the job and less coworker support were found
to be significantly associated with certain symptoms (numbness). The
limitations of this study are the low participation rate, although the
non-responders were followed up and the non-specific nature of the
health outcome.
Leclerc et al., 1999 ( Ex. 500-118-2) conducted a longitudinal
study to evaluate the effects of prevention programs at the workplace
aimed at reducing back, neck, and shoulder morbidity among active
workers. The intervention group (294 workers) and the referent group
(294 workers) were collapsed and analyzed as a whole. Health outcome
was based on two questionnaires. Questions ``focused more on the
potential risk factors for low back pain, such as bending forward and
backward, twisting, and handling of materials.'' The authors note that
``the role of specific occupational risk factors of neck disorders,
such as awkward postures of the head and neck and static postures, was
not studied because these variables were not included in the
questionnaire.'' Analyses were performed with ``occupation'' as a crude
indicator of occupational exposure. Female gender, older age, headaches
or pain in the head, psychological distress, and psychosomatic problems
were predictors of neck pain. This study found that there was no
significant difference in occurrence of neck pain among the different
occupations--hospital workers, warehouse workers, and office workers.
This is not surprising, as many studies have found increased rates of
neck symptoms in these occupational groups. What is lacking in this
study, as admitted by the authors, is adequate assessment of risk
factors known to be associated with neck MSDs. The poor exposure
assessment concerning occupational factors does not detract from the
relationship of exposure to certain work factors and neck disorders.
Because of its failure to address specific work factors related to neck
disorders, OSHA does not regard this study as adequate and it was not
included in Table V-1.
Eriksen et al., 1999 (Ex. 500-118-2) carried out a community-based
4-year prospective study of 1429 working Norwegians who completed a
questionnaire in 1990, and returned a second questionnaire 4 years
later. The participation rate was 67% of original group in 1990; 79.8%
of working group from 1990 responded to 2nd questionnaire in 1994. The
health outcome was based on the Nordic questionnaire, ``presence of any
neck pain during the previous 12 months.'' Workplace exposure also
relied on questionnaire data. Questions concerned work with hands over
shoulder-level, static work positions, repetitive stereotypic
movements, heavy lifting, sitting, standing, and high work pace. The
authors note that the responders in 1994 were ``less inclined to have
jobs that required them to spend a large amount of time with hands
above shoulder level, jobs that required a large amount of standing,
and jobs that required a large amount of heavy lifting.'' This
admission, without providing further data, makes interpretation of
results difficult. It is impossible to tell whether the study sample
reflects the overall original sample population. By loss of those
exposed to heavy lifting or working with hands above shoulder one
cannot assess
[[Page 68448]]
whether this would have minor or major impact on the findings. Changes
in job situations after 1990 were also not recorded, which would weaken
association between job factors and neck pain. In responders without
neck pain during the previous 12 months in 1990, the ``little influence
on own work situation'' factor predicted neck pain during the previous
12 months (odds ratio = 2.21; 95% confidence interval, 1.18 to 4.14)
and previous 7 days in 1994 (OR = 2.85; 95% confidence interval, 1.21
to 6.73) after adjustment for a series of potential confounders.
Because of the serious questions with regard to changes in population
exposure over time, OSHA believes the results are not interpretable and
it was not included in Table V-1.
Biomechanical Evidence
In a series of biomechanical and EMG studies, Harms-Ringdahl (1986,
Ex. 26-1128) demonstrated that considerable stress is generated in the
ligaments and joint capsule of the cervical spine with extreme neck
flexion (more than 45 degrees). The extensor muscle activity is less
than in the neutral position while the load moment (or torque) is 3-4
times greater in extreme flexion.
Many hand-intensive jobs and tasks require static neck contraction
to permit accuracy in task performance. Thus, significant muscle stress
and fatigue may occur with maintenance of static neck postures required
in many office and assembly workplace settings (Hales and Bernard 1996,
Ex. 26-896; Bernard and Fine 1997, Ex. 26-1; Onishi, Sakai, and Kogi
1982, Ex. 26-991; Stock 1991, Ex. 26-1010; Westgaard and Bjorklund
1987, Ex. 26-239). In confirmation of this postulate, several EMG
studies have documented the increase in neck and upper back muscle
activity from static work (Erdelyi et al.1988, Ex. 26-619; Onishi,
Sakai, and Kogi 1982, Ex. 26-991; Schuldt et al.1987, Ex. 26-670).
Hidalgo et al., 1992 (Ex. 26-631) reviewed the biomechanical literature
of the neck and proposed that prolonged static contraction of neck
muscles be limited to force levels at or below 1% of maximum voluntary
contraction (MVC).
It has also been shown that workplace interventions to mitigate
static loading of neck muscles reduce pain, time out of work due to
musculoskeletal problems, and EMG measured loading. Aaraas (1994a, Ex.
26-892; 1994b, Ex. 26-62) evaluated users of video display terminals
(VDTs) and assembly workers before and after ergonomic interventions
consisting of changes in the workstations, tools, and work organization
alterations. In assembly workers, mean static trapezius load decreased
from 4.3% to 1.4% of MVC, and in VDT users, MVC declined from 2.7% to
1.6%. This was accomplished with more accessible tool placement and
support for elevated arms. The median duration for sick leave resulting
from MSDs dropped from 23 to 2 days per person/year. As a result of
interventions, including the reduction in trapezius loading, the VDT
operators also reported less intensity and duration of pain in the neck
and shoulder region. The study design did not permit the determination
of which intervention(s) were responsible for the decline in MVC and
sick leave, but it does support the role of workplace ergonomics.
While epidemiologic studies regarding vibration and non-discogenic
neck and shoulder pain have been inconclusive, there is some
biomechanical evidence that vibration may affect muscle activity, and
therefore could be pathogenic for neck disorders. This is a complex
area, particularly since the most common shoulder diagnoses--
impingement and rotator cuff tendinitis--are clinically useful but
without very specific pathophysiologic meaning. In the following review
(Appendix I, Ex. 27-1), the neck, but not the shoulder, is shown to be
associated with a vibration-related pathology. The separation of
biomechanical, physiologically adaptive, and vibration-specific factors
is especially difficult for the neck and shoulder. Scapular stability
and posture are the heart of large-muscle activation sequences
involving efficient distal muscle group movement (Mackinnon and Novak
1997, Ex. 26-1309). Moreover, static shoulder posture, important for
tool stabilization, is an important contributor to early arm fatigue
(Sjogaard et al.1996, Ex. 26-213). Finally, the quality of a vibratory
stimulus (continuous or discrete) has significant impacts on efferent
recruitment and firing (Maeda et al.1996, Ex. 26-562). The combined
effects of this complexity are not easily modeled. This is all the more
reason why neck/shoulder symptoms should be carefully scrutinized when
a power tool is part of the exposure background. It may prove difficult
in practice to distinguish neck/shoulder symptoms that have their
origins in strictly biomechanical processes from vibration-induced
injuries. However, there is sufficient evidence in support of an
etiology to merit intervention.
As discussed earlier, skeletal muscle activity involves oxygen and
energy consumption and metabolic end-product generation. Repeated
damage from overuse without adequate recovery time for repair therefore
has the potential to cause permanent structural damage to skeletal
muscle (Armstrong et al.1993, Ex. 26-1110). Thus, work pacing can
reasonably be expected to affect muscle function in the neck. Froberg
et al.(1979, Ex. 26-117) compared female production workers performing
piece work vs. salaried work. Piece work was associated with increased
pain in the shoulders, arms, and back, accompanied by elevated
excretion of adrenalin and noradrenalin.
Unfortunately, financial incentives in piece workers may encourage
workers to avoid pacing themselves in an effort to exceed production
levels. Brisson et al.(1989, Ex. 26-937) postulated that the
biomechanical stressors involved with piece work performed by female
garment workers in Quebec, and the time pressures imposed by their
piece work, combined to account for observed disability from MSDs. The
association was related to the number of years performing piece work,
and was independent of age, smoking, education, and total length of
employment. In addition, some researchers suggest that workers may
ignore early warning symptoms of work-related MSDs.
Conclusion
The 1997 NIOSH report concluded the following with regard to
physical work factors and MSDs of the neck/shoulder region:
There is strong evidence that working groups with high levels of
static contraction, prolonged static loads, or extreme postures
involving the neck/shoulder muscles are at increased risk for neck/
shoulder MSDs. Consistently high ORs were found (twelve
statistically significant studies with ORs over 3.0) providing
evidence linking tension neck syndrome with static postures and
static loads (Ex 26-1).
OSHA agrees with NIOSH with regard to the epidemiological evidence for
an association between neck and neck/shoulder MSDs and physical risk
factors related to forceful exertion, repetitive motion and awkward
posture. Twelve out of thirteen well-conducted epidemiological
investigations that directly observed or measured these factors in the
workplace have found a significantly elevated risk of neck/shoulder
MSDs in exposed workers verified by physical exam. This link between
physical work factors and injury has been established across numerous
job areas including VDT operation (Hunting 1981, Ex. 26-1276;
electronics manufacture (Kilbom 1986, Ex. 500-41-75; Jonsson 1988, Ex.
26-969) and fish processing (Nordander 1999, Ex 38-408). Several
reviews have concluded that specific neck disorders, such as tension
neck syndrome, are
[[Page 68449]]
consistently associated with repetitive work and prolonged static loads
and postures of the neck (Hagberg et al.1995, Ex. 26-432; Kourinka and
Forcier 1995, Ex 26-432; Grieco et al.1998, Ex. 26-627).
The epidemiological evidence is supported by what is known about
the biomechanics and pathogenesis of these neck disorders. It has been
consistently shown by EMG that extreme postures and static loads on the
neck/shoulder increase the internal force on the neck muscles Harms-
Ringdahl et al.1986, Ex. 26-136; Higado et al.1992, Ex. 26-631).
Prolonged and frequent stress on these structures leads to muscle
fatigue and reduced blood flow. The combination of high oxygen demand
and low supply creates ischemia of the surrounding tissue and neck
pain. Repeated episodes of stress does not allow adequate recovery time
for repair raising the potential for long-term damage to the neck
muscles (Armstrong 1993, Ex. 26-1110). OSHA concludes that a
combination physical work-related factors, such as repeated movements
of the upper arm and shoulder, static loads on the neck/shoulder, and
extreme postures of the neck, are able to cause substantial and serious
impairment to the neck and shoulder.
Muscoskeletal Disorders of the Shoulder
Much of the evidence that relates physical work factors to shoulder
disorders focuses on shoulder tendinitis. To understand how force,
repetitive motion, and awkward postures lead to tendon injury one must
understand tendon function and repair mechanisms. As muscles contract,
tendons are subjected to mechanical loading and viscoelastic
deformation. Tendons must have both tensile resistance to loading (to
move attached bones) and elastic properties (to enable them to move
around turns, as in the hand). When collagen bundles are placed under
tension, they first elongate without significant increase in stress.
With increased tension, they become stiffer in response to this further
loading. If the load on these structures exceeds the elastic limit of
the tissue (its ability to recoil to its original configuration),
permanent changes occur (Ashton-Miller 1999, Ex. 26-414; Moore 1992a,
Ex. 26-985; Chaffin and Andersson 1991, Ex. 26-420). During subsequent
loading of the damaged tendon, less stiffness is observed. The ultimate
strength of normal tendon and ligament is about 50% of that of cortical
bone (Frankel and Nordin 1980, Ex. 26-1125), but structures that have
exceeded the elastic limit fail at lower limits. In addition, if
recovery time between contractions is too short, deformation can result
in pathologic changes that decrease the tendon's ultimate strength
(Thorson and Szabo 1992, Ex. 26-1171; Goldstein et al.1987, Ex. 26-
953). Tendon exhibits additional viscoelastic properties of relaxation
and creep. That is, when a tendon is subjected to prolonged elongation
and loading, the magnitude of the tensile force will gradually decrease
(relaxation) and the length of the tendon will gradually increase
(creep) to a level of equilibrium (Chaffin and Andersson 1991, Ex. 26-
420; Moore 1992a, Ex. 26-985; Woo et al.1994, Ex. 26-596). During
repetitive loading, the tendon exhibits these properties and then
recovers if there is sufficient recovery time. If the time interval
between loadings does not permit restoration, then recovery can be
incomplete, even if the elastic limit is not exceeded (Goldstein et
al.1987, Ex. 26-953).
Shoulder tendinitis includes supraspinatus and bicipital
tendinitis. Bicipital tendinitis results when the tendon of the biceps
brachii muscle rubs on the lesser tuberosity of the humerus bone, which
occurs with motion of the shoulder (glenohumeral) joint during overhead
arm movements. Persons affected with this disorder experience pain and
tenderness in the shoulder area during shoulder flexion, elbow
extension and forearm supination, or when the elbow and arm are
extended and the forearm is supinated. Supraspinatus tendinitis is also
known as rotator cuff disorder, subdeltoid tendinitis, subacromial
tendinitis, or partial tear of the rotator cuff. Affected individuals
commonly have pain in the front of the shoulder which is accentuated
when they attempt to raise the arm away from the body (abduct the arm),
although other movements may also be painful.
There are multiple plausible theories for the pathogenesis of
disorders of the rotator cuff. For purposes of this review, it is
assumed that supraspinatus tendon tears and calcification represent
endpoints of one pathological process as opposed to separate and unique
endpoints. Mechanisms related to disorders of the rotator cuff complex
with acute onset are excluded from this discussion (e.g., strains,
falls, dislocations).
The presence of a watershed or avascular zone in the supraspinatus
tendon has been described and demonstrated by several investigators
(Moseley and Goldie 1963, Ex. 26-306; Rothman and Parke 1965, Ex. 26-
499; Rathbun and Macnab 1970, Ex. 26-1376). It is believed that the
avascular zone compromises the ability of the tenocytes within this
portion of the tendon to repair damage to collagen fibers or their
matrix. This impaired ability to repair the tendon implies that
degenerative changes within this portion of the tendon will accumulate
over time; therefore, the degree and progression of tendon degeneration
will increase with increasing exposure to potential sources of injury,
age, or both. Potential sources of injury to the tendon's collagen
fibers or matrix may be ischemic, mechanical (impingement), or
physiological (contractile load).
According to the ischemia theory, the function and viability of the
tenocytes within the supraspinatus tendon are compromised because they
are in an avascular zone; therefore, they are unable to sustain the
normal structure of the tendon over one's lifetime. This lack of
maintenance manifests itself as degenerative changes within the
substance of the tendon. The positive correlation between the
prevalence of supraspinatus tendon degeneration and tears with age is
consistent with this theory. It is not clear that task variables
related to work are necessary in this pathogenetic model; however,
Rothman and Macnab (1970, Ex. 26-499) postulated that shoulder
adduction with neutral rotation would subject this avascular portion of
the tendon to pressure from the humeral head, thus ``wringing out'' the
blood from this already avascular area. If this were true, the duration
of shoulder adduction is probably more important than the number of
shoulder adductions.
Neer (1972, Ex. 26-185) proposed that the subacromial bursa and
supraspinatus tendon were mechanically impinged on the underside of the
anterior aspect of the acromion process or coracoacromial ligament as
the shoulder approached 80 degrees abduction or flexion when internally
or externally rotated. Below 80 degrees flexion or abduction, the
greater tuberosity of the humerus is generally not in immediate contact
with the acromion process or the coracoacromial ligament. Beyond this
degree of elevation, the humeral head is displaced down and away from
the acromion and the ligament, thus relieving these structures of this
contact stress. This contact stress is postulated to cause disruption
of collagen fibers within the tendon mechanically. This mechanism of
collagen disruption may (or may not) be combined with the phenomenon of
impaired healing related to the avascular zone. The critical
relationship between this proposed model of supraspinatus tendon
disease and biomechanical task variables is the passage of the shoulder
[[Page 68450]]
through the 80 degrees abduction or flexion arc. Since this
biomechanical stress occurs in a limited portion of these arcs, it is
anticipated that the number of times the shoulder performs this task
(per unit time) is more relevant than the duration of time the shoulder
is in this position. Anatomical variations in the size and shape of the
acromion (particularly type II [curved] and type III [hooked]) as well
as hypertrophy of tissues related to the coracoacromial arch are also
important factors. (Bigliani et al.1991, Ex. 26-603; Fu, Harner, and
Klein 1991, Ex. 26-464).
Posture plays an important role in rotator cuff tendinitis of the
shoulder. Work with the arm elevated more than 60 degrees from the
trunk is more stressful for the supraspinatus than work performed with
the arm at the trunk. As the arm is raised or abducted the
supraspinatus tendon becomes in contact with the undersurface of the
acromion. They are in closest proximity between 60 and 120 degrees of
arm elevation (Amadio 1995, as cited in Fine and Silverstein 1998,
Ex.38-444). The precise pathosphysiology of rotator cuff tendinitis is
not known. However, the role of overhead work, particularly of a static
nature or very forceful exertions, is likely a crucial event (Andersson
1995 and Levitz and Iannotti 1995, as cited in Fine and Silverstein,
1998, Ex. 38-444). Impingement seems important. One suggested
histologic pattern is a reversible inflammatory infiltrate, with
increased vascularity and edema within the rotator cuff tendons,
especially the supraspinatus tendon. This process, if it becomes
chronic, has been postulated as leading to degenerative changes in the
tendons. Eventually, enough degeneration occurs that a minor trauma
causes or seems to cause a partial rotator cuff tear (Fine and
Silverstein 1998, Ex. 38-444).
Another shoulder disorder related to physical work factors is
osteoarthritis of the acromioclavicular joint. Osteoarthritis refers to
degenerative changes in the cervical spine that are apparent on
radiological examination. A combination of high exposure to load
lifting and high exposure to sports activities that engage the arm was
a risk factor for shoulder tendinitis, as well as osteoarthritis of the
acromioclavicular joint (Stenlund et al.1993, Ex. 26-1459). Kennedy,
Hawkins, and Kristof (1978, Ex. 26-1135) found that 15% of competitive
swimmers with repetitive overhead arm movements had significant
shoulder disability, primarily due to impingement from executing
butterfly and freestyle strokes.
Physical work requires both mechanical and physiological responses,
for example, muscle force and energy consumption. The mechanical
responses include connective tissue deformation and yielding within the
muscle; which increases intramuscular pressure. Increased intramuscular
pressure in turn decreases blood flow through the muscle (Armstrong et
al.1993, Ex. 26-1110).
Nerves, vessels, and other soft tissues may be internally
compressed under conditions of high-force exertions, awkward postures,
static postures, and/or high velocity or acceleration of movement. For
example, strong abduction or extension of the upper arm, as well as
awkward postures of the neck, can compress parts of the brachioplexus
under the scalene muscles and other anatomical structures. This
compression can result in nerve and/or blood vessel damage or eventual
damage to the tissues served by these nerves and vessels.
Static postures, postures held over a period of time to resist the
force of gravity or to stabilize a work piece--are particularly
stressful to the musculoskeletal system. More precisely, static
postures are usually defined as requiring isometric muscle force--
exertion without accompanying movement. Even with some movement, if the
joint does not return to a neutral position and continual muscle force
is required, the effect can be the same as a non-moving posture. Since
blood vessels generally pass through the muscles they supply, static
contraction of the muscle can reduce blood flow by as much as 90%. The
consequent reduction in oxygen and nutrient supply and waste product
clearance results in more rapid onset of fatigue and may predispose
muscles and other tissues to injury. The increased intramuscular
pressure exerted on neural tissue may result in chronic decrement in
nerve function. The viscoelastic ligament and tendon tissues can
exhibit ``creep'' over time, possibly reaching failure thresholds
beyond which they are unable to regain resting length.
Chronic reduction of blood flow may be a mechanism by which static
muscle contractions lead to MSDs. Several studies have found that the
small, slow motor units in patients with chronic muscle pain show
changes consistent with reduced local oxygen concentrations (Larsson et
al.1988, Ex. 26-1140; Dennett and Fry 1988, Ex. 26-104). Reduced blood
flow and disruption of the transportation of nutrients and oxygen can
produce intramuscular edema (Sjogaard 1988, Ex. 26-206). The effect can
be compounded in situations where recovery time between static
contractions is insufficient. Eventually, a number of changes can
result: muscle membrane damage, abnormal calcium homeostasis, an
increase in free radicals, a rise in other inflammatory mediators, and
degenerative changes (Sjogaard and Sjogaard 1998, Ex. 26-1322).
Epidemiological Evidence
In its review of the epidemiologic literature on work-related
musculoskeletal disorders of the shoulder, NIOSH identified 38
epidemiologic studies that examined workplace factors and their
relationship to shoulder MSDs (Bernard 1997, Ex. 26-1). These studies
examined the prevalence of shoulder disorders in workers exposed to
repeated abduction extension or flexion of the shoulder in combination
with strenuous work involving heavy loads or elevated arms. The MSDs
were usually shoulder tendinitis or a collection of symptoms defined by
stiffness, pain, and weakness. Table V-2 summarizes some key aspects of
these investigations, such as the occupations examined, the
biomechanical risk factors the workers were exposed to, whether
exposures were directly observed or measured during the study, and
whether the health outcomes were verified by trained medical personnel
during physical examination. Sixteen of the studies relied on direct
observation or measurements of exposure and verification of shoulder
injury by physical exam. EMG of the forearm flexor muscles, frequency
of shoulder movements, or angle of shoulder flexion were quantitatively
measured in some of these studies. Another 24 studies relied either on
job title information or questionnaire to obtain exposure information
and/or used self-reported symptoms to define cases of shoulder MSDs.
OSHA considers these investigations to be less reliable. All twelve
studies with exposure and medical verification reported statistically
significant associations between shoulder disorders and the physical
work factors. The odds ratios reported in these studies ranged between
1.6 and 46. The wide range in risks probably relates to differences in
magnitude of exposure and case definition among the studies.
[[Page 68451]]
Table V-2.--Summary of Epidemiology Studies Examining Musculoskeletal Disorders of the Shoulder
----------------------------------------------------------------------------------------------------------------
Job type Physical Physical Risk measure (95%
Study studied factors Exposure basis exam CI) 1
----------------------------------------------------------------------------------------------------------------
Hughes (1997) Ex. 26-907.... Aluminum F/R?/P Checklist...... Yes......... OR=46 *
smelter. (3-550)
Herberts (1981) Ex. 26-51; Shipyard F/R?/P Observation EMG Yes......... PRR=15-18 *
(1984) Ex. 26-960. welding. (14-22)
Bjelle (1979) Ex. 26-1112... Industry case F?/R/P Observation.... Yes......... OR=10.6 *
control. (2.3-54.9)
Frost (1999) Ex. 500-205-4.. Slaughter-house F/R/P Observation.... Yes......... OR=5.3-7.9 *
(2.9-21.2)
Onishi (1976) Ex. 26-1222... Multiple jobs.. F/R/P Observation Yes......... OR=1.1-6.0 *
cycle time. (3.0-12.2)
Ohlsson (1995) Ex. 26-868... Assembly line.. F?/R/P Flexion cycle Yes......... OR=4.2 *
time. (1.4-13.2)
Baron (1991) Ex. 26-967..... Grocery F/R/P Job titles..... Yes......... OR=3.9 *
checking. (1.4-11.0)
Ohlsson (1994) Ex. 26-1189.. Fish processing F/R/P Observation Yes......... OR=3.5 *
freq./angles. (1.6-7.2)
Nordander (1999) Ex. 38-408. Fish processing F?/R/P Observation.... Yes......... OR=3.5 *
(2.5-5.3)
Punnet (2000) Ex. 500-41-109 Auto workers F/R/P Cycle/ Yes......... OR=1.1-4.0 *
case/control. flexionlift (1.7-9.4)
load.
Chiang (1993) Ex. 26-1117... Fish processing F/R/P? Cycle time EMG. Yes......... OR=1.6-1.8 *
(1.2-2.5)
Kilbom (1987) Ex. 26-1277; Electronics F/R/P MVC, flexion Yes......... NR *
Jonsson (1988) Ex. 26-833. manufacture. cycle time.
Bjelle (1981) Ex. 26-1519... Industrial F/R/P Flexion EMG.... Yes......... NR *
plant.
Sakakibara (1995) Ex. 26-800 Fruit bagging.. F?/R?/P Observation arm Yes......... NR *
elevation.
Zetterberg (1997) Ex. 26-899 Auto assembly.. F/P Cycle time tool Yes......... NR
weight.
English (1995) Ex. 26-848... Patients case/ F/R/P Question- naire Yes......... OR=2.3 *
control. (NR)
Andersen (1993) Ex. 26-1451. Sewing machine. F/R/P? Job titles..... No.......... OR=3.2 *
(1.7-7.4)
Andersen (1993) Ex. 26-1502. Sewing machine. F/R/P? Job titles..... Yes......... NR *
Stenlund (1992) Ex. 26-733; Rockblasting V/F/R? Questionaire... Yes......... OR=0.4-4.0 *
(1993) Ex. 26-1459. bricklaying. (1.8-9.2)
Wells (1983) Ex. 26-729..... Letter carrier. F/R?/P Job title...... No.......... OR=5.7 *
(2.1-17.8)
Hoekstra (1994) Ex. 26-725.. Video terminal. R/P Observation.... No.......... OR=5.1*
(1.7-15.5)
Schibye (1995) Ex. 26-1463.. Sewing machine. F?/R/P? Questionaire... No.......... NR
Burdorf (1991) Ex. 26-454... Riveting....... V Tool No.......... OR=1.5 *
aceleration. (NR)
Bergenudd (1988) Ex. 26-1342 Multiple F/R?/P? Questionnaire.. No.......... NR
industries.
Burt (1990) Ex. 26-698...... Computer entry. R/P Job title...... No.......... OR=2.6-4.1 *
(1.8-9.4)
Floodmark (1992) Ex. 26-1209 Vent shaft F?/R?/P? Job title...... No.......... OR=2.2 *
production. (1.4-4.4)
Hales (1989) Ex. DC-139-D... Poultry F/R Job title...... Yes......... OR=0.9-3.8 *
processing. (0.6-22.8)
Hales (1994) Ex. 26-131..... Telecommunicati R/P Questionnaire.. Yes......... NR
on.
Ignatius (1993) Ex. 26-1389. Postal work.... F/R/P Job title...... No.......... OR=1.8-2.2 *
(1.5-3.1)
Kiken (1990) Ex. 26-430..... Poultry F/R/P? Job title...... Yes......... OR=1.6-4.0
processing. (0.6-29)
Kvarnstrom (1983) Ex. 26- Factory/office. F/R/P? Questionnaire.. Yes......... RR=2.2-5.4
1201. (NR)
McCormick (1990) Ex. 26-1334 Textile........ F/R/P? Job title...... Yes......... OR=1.1-1.3
(0.5-3.8)
Ohara (1976) Ex. 26-1....... Cash register.. F?/R?/P? Job title...... Yes......... OR=1.7-2.2 *
(1.4-3.5)
Ohlsson (1989) Ex. 26-1290.. Auto assembly.. F/R/P? Job title...... No.......... OR=2.0-3.4 *
(1.6-7.1)
Punnett (1985) Ex. 26-995... Garment........ R/P? Job title...... Yes......... OR=2.2 *
(1.0-4.9)
Rossignol (1987) Ex. 26-804. Computer R/P Questionnaire.. No.......... OR=2.5-4.8 *
operation. (1.6-17.2)
Sweeney (1994) Cited Ex. 26- Sign language R/P? Questionnaire.. Yes......... OR=2.5
1. interpreter. (0.8-8.2)
De Zwart (1997) Ex. 26-617.. Various F/R?/P? Questionnaire.. No.......... OR=1.25-2.5 *
occupations. (p0.001)
[[Page 68452]]
LeMasters (1998) Ex. 500-121- Carpenters..... F/R/P Observation, Only small OR=2.3-3.2 * (1.1-
44; Bhattacharya (1997) Ex. measurement. subset. 8.9)
500-121-7; Booth-Jones
(1998) Ex. 500-121-9.
Pope (1997) Ex. 32-137-1-4.. Various F/R?/P Questionnaire.. No.......... OR=2.1-5.5 *
occupations. (1.8-17.4)
Botha (1998) Ex. 500-121-10. Nurses......... F/R?/P Questionnaire, No.......... NR
observation.
De Joode (1997) Ex. 500-121- Ship F/R?/P Strain gauge... No.......... RI=1.7-3.9
72. maintenance. (NR)
----------------------------------------------------------------------------------------------------------------
F=forceful exertions; R=repetitive motion; P=awkward posture; IR=incidence rate; OR=odds ratio; PRR=prevalence
rate ratio; RI=risk index; NR=not reported; ?=presence of risk factor unclear.
* p0.05.
1 95% confidence interval expressed for the upper end of the risk measure range.
The NIOSH noted several well-conducted studies that provided
evidence of an exposure--response and temporal relationships. Chiang et
al.(1993, Ex. 26-1117) divided 207 fish processing workers into three
exposure groups based on EMG measurements of forearm flexor muscles and
cycle time measurements of shoulder movements of representative job
tasks. Exposure groups were: (1) Low force, low repetition (comparison
group); (2) high force or high repetition; and (3) high force and high
repetition. Shoulder girdle pain was the health outcome as defined by
symptoms and palpable hardenings upon physical examination. The results
showed a significant increasing trend in the prevalence of shoulder
pain from group 1 (10 percent) to group 3 (50 percent).
In another cross-sectional study, Ohlsson et al.(1995, Ex. 26-868)
compared a group of 82 women who performed industrial assembly work
requiring repetitive arm movements with static muscular work of the
neck/shoulder with a referent group of unexposed women. The frequency,
duration, and critical angles of movement were measured from videotape
and observation. Shoulder MSDs such as tendinitis, acromicroclavicular
syndrome, and frozen shoulder were determined from symptoms and
physical exam. The risk of shoulder tendinitis in the exposed women was
significantly greater than the unexposed women (OR=4.2; 95% CI 1.4-
13.2). The neck and shoulder disorders were also significantly (p0.05)
associated with the number and duration of shoulder elevations greater
than 60 degrees. The study of Bjelle et al.(1981, Ex. 26-1519) also
found that the frequency of shoulder abduction and forward flexion past
60 degrees was significantly greater (p0.05) for cases with neck/
shoulder disorders than for controls.
In a prospective study design, Kilbom et al.(1986, Ex. 500-41-75;
1987, Ex. 26-1277) assessed the health and exposure status of 06
electronics manufacturing plant employees over a two year period. The
employees were evaluated for maximum voluntary isometric contraction
(MVC) of the forearm flexors and shoulder strength. Videotape was used
to analyze cycle time and working postures and movements. Shoulder MSDs
were determined annually based on interview and physical examination
assessing tenderness on palpation as well as pain and restriction upon
shoulder movement. Symptom severity was also scored. Logistic
regression analysis showed significant relationship (p0.05) between
MSDs and percentage of work cycle time with upper arm elevated. The
number of elevations per hour was a strong predictor for increases in
symptom severity over the study period. A follow-up investigation also
found that the percent of the work cycle spent with the shoulder
elevated was negatively associated with remaining symptom-free (Jonsson
et al.1988, Ex. 26-833).
NIOSH concluded that there was evidence for a positive association
between highly repetitive work and shoulder MSDs. Only three studies
specifically address the health outcome of shoulder tendinitis and
these studies involve combined exposure to repetition with awkward
shoulder postures or static shoulder loads. The other six studies with
significant positive associations dealt primarily with symptoms. There
was evidence for a relationship between repeated or sustained shoulder
posture with greater than 60 degrees of flexion and abduction and
shoulders MSDs. This holds for both shoulder tendinitis and nonspecific
shoulder pain. NIOSH found insufficient evidence for a positive
association between either force or vibration and shoulder MSDs because
the studies that principally examined this risk factor relied on self-
reported questionnaires for assessment of exposure and health outcome.
Twelve studies that address physical work factors and shoulder MSDs
were submitted into the OSHA docket following publication of the
proposal (Zetterberg et al.Ex. 26-899; De Zwart et al.1997, Ex. 500-
121-18; Punnett et al.2000, Ex. 500-41-109; LeMasters et al.Ex. 500-
121-9; Bhattacharya et al.1997, Ex. 500-121-7; Booth-Jones et al.1998;
Ex. 500-121-44; Pope et al.1997, Ex. 500-71-42; Frost and Anderson
1999, Ex. 500-41-57; Burdorf et al.1997, Ex. 500-71-24; Van Wendel de
Joode 1997, Ex. 500-121-72; Botha and Bridger 1998, Ex. 500-121-10).
Many of these studies showed that high physical loads in combination
with elevated shoulder positions were associated with increased
prevalence of shoulder disorders (Ex. 500-121-9; Ex. 500-121-7; Ex.
500-121-44; Ex. 500-41-57; Ex. 500-41-109; Ex. 500-121-18; Ex. 500-121-
10; Ex. 500-121-72; Ex. 26-899). For example, Frost and Anderson (Ex.
500-41-57) found a strong significant association (OR>5) among meat
packers who worked extensively with arm elevation greater than 30
degrees more than 10 times per minute and prevalence of rotor cuff
tendinitis compared to those with no shoulder elevation. The risk
increased with cumulative exposure years. Punnett et al.(Ex. 500-41-
109) reported a significant association between repeated shoulder
abduction/flexion and shoulder disorders. There was evidence of
exposure--response with frequency of shoulder movements to 90 degrees
flexion or abduction. Shoulder
[[Page 68453]]
MSDs were confirmed by physical examination in both studies.
Biomechanical Evidence
Rohmert (1973, Ex. 26-580) found that muscle contractions can be
maintained for prolonged periods if kept below 20% of MVC. But other
investigators (Westgaard and Aaras 1984, Ex. 26-1026) found chronic
deleterious effects of contractions even if they are lower than 5% of
MVC. This latter finding is supported by the observation that low-level
static loading (such as shoulder loading in keyboard tasks) is
associated with shoulder MSDs (Aaras et al.1998, Ex. 26-597). The
supraspinatus muscle, a muscle severely constrained by bone and
ligamentous tissue, demonstrates increased intramuscular pressure
during small amounts of shoulder abduction or flexion (Jarvholm et
al.1990, Ex. 26-285). Tichauer (1966, Ex. 26-1172) looked at the impact
of arm posture on trapezius stress. He noted that arm abduction to 40
degrees increased stress in the upper trapezius muscle eight times as
much as when the arm was abducted to 20 degrees, and 64 times as much
as at a 10 degrees. These study results suggests the possibility of
chronic blood vessel and nerve compression during static tasks. Other
laboratory evidence for muscle and tendon damage in these areas, as
well as secondary compression of blood vessels and nerves, lends
support to the connection between work-related static postural
requirements and the development of these disorders.
Biomechanical studies of shoulder posture show that muscle activity
and subjective fatigue in the shoulder region increases as a function
of shoulder elevation angle and load moment at the shoulder joint.
There is also evidence of localized muscle fatigue based on a shift in
the MPF of the EMG spectrum. Prolonged periods of neck flexion cause
increased levels of discomfort and increased EMG activity in the neck
extensor muscles.
Herberts, Kadefors, and Broman (1980, Ex. 26-1129) measured EMG
activity as a function of static shoulder posture in a laboratory study
using 10 male subjects. The primary independent variable was posture.
Subjects held a 2-kg load in the hand at waist, shoulder, and overhead
heights using different combinations of flexion and abduction at the
shoulder. EMG activity was measured using wire electrodes in the
anterior and posterior portions of the deltoid, the supraspinatus, the
infraspinatus, and the upper portion of the trapezius. Localized
fatigue (a shift in EMG mean power frequency [MPF]) was observed in all
muscle groups during shoulder-level and overhead work (p.05) during the
1-minute trials. Even at waist level, fatigue was observed when the
upper arm was abducted at an angle of 30 degrees.
Hagberg (1981, Ex. 26-955) measured EMG activity and discomfort in
the shoulder in a laboratory study of six female subjects. Surface
electrodes recorded EMG activity in the descending trapezius, anterior
deltoid, and biceps brachii while subjects performed repeated flexion
of the shoulder every 4 seconds to an angle of 90 degrees for a period
of 60 minutes. Heart rate and perceived exertion using Borg's scale was
also recorded. Hand load was the independent variable: weights of 0.6
kg, 1.6 kg, and 3.1 kg were held in the hand (in addition to a no-load
treatment). Heart rate and perceived increased over the course of the
trial. Heart rate and perceived were greater when a load was held in
the hands. EMG activity in the trapezius was closely correlated with
the external moment at the shoulder joint.
Oberg, Sandsjo, and Kadefors (1994, Ex. 26-867) measured EMG
activity and subjective discomfort in the shoulder-neck region in a
laboratory study of 20 subjects (10 male, 10 female). Surface
electrodes measured EMG activity in the right trapezius muscle while
subjects abducted the arm to a 90 degree angle. Subjects reported
fatigue using the Borg 10-point scale. Each subject was tested under
two conditions: a 5-minute test with no load in the hand and a 2.5
minute test with a 2-kg load in the hand. At the no-load level, there
was no change in EMG MPF over the course of the trial; however,
subjective fatigue increased. With the 2-kg. load, there was a small
linear decrease in MPF over the trial and there was a negative
correlation between MPF and the Borg rating = 0.46). The
authors concluded that MPF was not a good proxy for perceived fatigue
during low-intensity static exertions of the shoulder.
Using EMG, several investigators have demonstrated that the
supraspinatus muscle is activated throughout most of the range of
motion of the shoulder. Herberts and Kadefors (1976, Ex. 26-470) and
Herberts et al.(1984), Ex. 26-960 postulated that the level of tension
in the supraspinatus muscle during arm elevation (with or without
holding an object in the hands) was sufficiently high to increase
intramuscular pressure to a point sufficient to compromise
intramuscular circulation. As reported by Edwards, Hill, and McDonell
(1999; Ex. 26-1232), intramuscular pressures of 20 mm Hg may be
sufficient to prevent muscular perfusion. Since many of the blood
vessels within the tendon are longitudinal extensions of the blood
vessels in the muscle belly, reduced perfusion of the intramuscular
blood vessels implies reduced perfusion of the intratendinous blood
vessels. If this reduced perfusion is sustained for sufficient
durations of time, the tenocytes or other tendon components are
susceptible to ischemic injury. In terms of biomechanical task
variables, experimental data suggest that overhead work may cause
intramuscular pressures capable of reducing intramuscular perfusion.
Lifting combined with arm elevation (shoulder load) also contributes to
the magnitude of supraspinatus muscle activation. From a temporal
perspective, this proposed model is more related to the duration of the
intramuscular pressure than to its frequency.
After reviewing the scientific literature, Winkel and Westgaard
(1992a, Ex. 26-1163) recommended less than 4 hours of work requiring
overhead or extended reach postures. For continuous work, they
recommended exposure times of one hour or less, particularly if the
work involved highly repetitive tasks, low worker control, or a lack of
alternating tasks. When large forces are also exerted, they recommended
that the exposure time should be even less.
Wiker, Chaffin and Langolf (1999; Ex. 26-1028) used psychophysical
methods to investigate the relationship between strength capacity of
the shoulder complex and fatigue/discomfort induced by sustained
awkward arm postures in simulated light assembly work. Awkward shoulder
postures (arms above shoulder level) produced severe discomfort at less
than 10% MVC within one hour and were unrelated to subject strength.
These authors recommended elimination of overhead work even in light-
weight manual assembly environments, irrespective of individual worker
strength or anthropometry.
Conclusion
The 1997 NIOSH report made the following statement with regard to
the epidemiological evidence that links physical work factors and
shoulder tendinitis:
The evidence for specific shoulder postures is strongest where
there is combined exposure to several physical factors like holding
a tool while overhead. The strength of the association was positive
and consistent in six studies that used diagnosed cases of shoulder
tendinitis or a combination of symptoms and physical findings
consistent with tendinitis as the health outcome (Ex. 26-1).
[[Page 68454]]
OSHA agrees with NIOSH with regard to the epidemiological evidence for
an association between shoulder tendinitis and a combination of
physical risk factors related to sustained or repeated shoulder flexion
and abduction, particularly when it includes an additional static hand
load such as working overhead. Fifteen out of sixteen well-conducted
epidemiological investigations that directly observed or measured these
factors in the workplace have found a significantly elevated risk of
shoulder MSDs in exposed workers verified by physical exam. This link
between physical work factors and injury has been established across
numerous job areas including assembly line work (Punnett et al.1998,
Ex. 38-155; Ohlsson et. al. 1995, Ex. 26-868), electronics manufacture
(Kilbom 1986, Ex. 500-41-75; Jonsson 1988, Ex. 26-969) and fish
processing (Nordander et al.1999, Ex 38-408; Chiang et al.1993).
The epidemiological evidence is supported by biomechanical studies
and the pathogenesis of these shoulder disorders. It has been
consistently shown by EMG that fatigue in the shoulder muscles occurs
with abduction and flexion of the shoulder. Addition of a static load
or requiring the arm/shoulder motion be performed repeatedly merely
increases both muscle fatigue and perceived discomfort. Over time,
these repeated actions stress the tendons in the shoulder causing
gradual loss of elasticity and strength. Once the damage exceeds the
reparative capacity of the tissue, ischemia sets in and the tendon
becomes inflamed, resulting in a chronic tendinitis. The rotator cuff
is particularly vulnerable to this pathology since muscles and tendons
are already somewhat constrained by ligaments and bone. Severe postures
can result in impingement of nerves and blood vessels further
aggravating the injury. OSHA concludes that sustained or repeated
exertions with the arms and shoulders in awkward postures, such as
raised overhead, can increase the risk of substantial and serious
impairment to the shoulder. During OSHA's hearing on it's proposal, a
nurse who injured her back at work provided compelling testimony.
Maggie Flannigan, a registered nurse with 19 years experience in
various newborn ICUs (intensive care units) across the country told her
story for inclusion in OSHA's rulemaking record. Ms. Flannigan reported
having back, neck and shoulder pain for years while working and also
after work. Then, while moving a 75-pound monitor down from, then back
onto a five-foot high shelf, she sustained a severe injury to her upper
back and shoulders. Ms. Flannigan said that other nurses had been
injured doing similar tasks, but because
when people think of newborn ICU, they think of, okay, you've got a
one-pound baby, so where are your stressors coming from? And they
don't realize that we are responding to alarms in high places, that
we're doing awkward postures and reaches, and we're pushing heavy
equipment, and then sometimes we actually lift heavy equipment
which, in my case, gave me a back injury.
It took Ms. Flannigan eight months of treatment to recover and
she is fearful of re-injury:
I'm fearful of what's going to happen to me as I age. And I'm
also fearful of losing my ability to work as a nurse. I love my
profession. I wouldn't trade it. * * * Since I've been injured at
work, my family really suffered. I couldn't bathe my children. I
couldn't dress them, couldn't do the laundry. My five-year-old
buckled my three-year-old in the car seat if I had to drive. He
pushed the cart at the grocery store--my five-year-old pushed the
shopping cart.
Ms. Flannigan stated further :
I know I'm not the first one hurt at my job, but what I can't
live with is I won't be the last unless we start protecting American
workers immediately with this ergonomic proposal so we can remove
the ergonomic hazards or reduce them in the workplace. American
workers deserve a place of employment free from recognized hazards
because when a worker develops an MSD, it's not just a lost workday.
It can be a life lost forever to pain and disability.
D. Disorders of the Upper Extremities
This section summarizes the evidence that exposure to physical risk
factors at work contribute to the pathogenesis of specific
musculoskeletal disorders (MSDs) of the upper extremities. In this
section, the upper extremities of interest are the elbow, forearm,
wrist, and hand. The bulk of the evidence demonstrating a work-related
risk center around five MSD classifications; these are epicondylitis,
tendinitis of the hand and wrist, carpal tunnel syndrome, hand-arm
vibration syndrome, and hypothenar hammer syndrome. There is an
impressive body of data that address the role of three biomechanical
risk factors in epicondylitis, tendinitis, and carpal tunnel syndrome.
These risk factors are force exerted on the muscle, tendons, and
nerves; repetitive motion involving the hands, wrists, and forearms;
and awkward postures of the wrist and arm. Exposure to these factors
often occurs concurrently in occupational settings and the evidence
shows that the risk of injury is greatest when more than one factor is
present. There are also studies that relate another biomechanical work
factor, vibration from the use of hand-held power tools, to an
increased risk of carpal tunnel syndrome and hand-arm vibration
syndrome. Repeated impact or contact stress, as well as vibration, have
been implicated in the development of hypothenar hammer syndrome.
Contact stress can, itself, be viewed as a specific combination of
repetitive motion and force applied directly to a localized area of
tissue, in this case the palm.
There are several types of evidence that continue to support force,
repetition, awkward posture, and vibration as causative factors for
MSDs of the upper extremities. Information on pathophysiology provides
evidence that links exposure to risk factors to the physiological,
anatomical, and pathological alterations in soft tissues of the upper
extremities. This speaks to the biologic plausibility that work-related
risk factors contribute to these injuries. There is voluminous
epidemiological data that provide evidence of associations between
worker exposure to the identified risk factors and the occurrence of
upper extremity MSDs. Some of these studies recently have been reviewed
by NIOSH (Bernard and Fine 1997, Ex. 26-1) and were discussed by OSHA
in the Health Effects Appendicies to the proposed rule (Ex. 27-1). For
the final rule, OSHA has evaluated many additional epidemiologic
studies that were entered into the record by many rulemaking
participants.
Finally, there is biomechanical and psychophysical laboratory
research that complement and corroborate the epidemiological evidence.
These approaches are able to directly link exposure to ergonomic risk
factors to biomechanical and subjective measurements of tissue response
under a more controlled set of simulated work conditions. This evidence
derives from studies reviewed in the Health Effects Appendices of the
Proposed Rule (Ex. 27-1) and testimony of the many expert scientists
that appeared at OSHA's rulemaking hearing. The evidence for each
specific MSD covered in this section is discussed in the parts that
follow.
Epicondylitis
Epicondylitis is a form of tendinitis that affects the forearm
extensor muscle-tendon units that extend from the hand and wrist to the
epicondyle (elbow). The most common type is lateral epicondylitis
(known as ``tennis elbow'') where the fibrous tissue at the bone-tendon
junction (usually the extensor carpi radialis brevis muscle/tendon) on
the outer elbow is inflamed. This is believed to be caused by repeated
microrupture of the tendon from overuse of the muscles that control the
[[Page 68455]]
wrists and fingers. Clinical case reports have noted that patients with
lateral epicondylitis were often in occupations that involved
repetitive, forceful work, particularly repeated pronation and
supination movements with the elbow fully extended. For example, in one
case series it was reported that 48 percent of patients with lateral
epicondylitis of unknown origin had occupations that involved gripping
tools with consequent repetitive supination/pronation of the forearm
(Sinclair 1965, Ex. 26-736). In a second smaller group of epicondylitis
patients reported on in the same publication, 88 percent worked in jobs
with constant gripping or repetitive movements.
National surveillance data consistently show that the incidence of
this injury is greatest in occupations requiring manually intensive
demands on the upper extremities in a dynamic work environment, such as
mechanics, butchers, and construction workers. This body of evidence
provides ample biological plausibility to the notion that force,
repetition, and awkward posture can contribute to this MSD. The
interplay between pathophysiology and physical work factors is
concisely summarized by Dr. Niklas Krause in his written testimony on
the proposed ergonomic standard (Ex. 37-15).
There always seems to be a mechanical overuse component in MSDs.
Tissues react to mechanical stress or overuse or microtraumitization
(whatever term is being used) with inflammation leading to edema,
swelling, pain, and local repair mechanisms that lead to stiffness
and reduced muscle elasticity (probably due to microadhesions of
muscle and tendon sheets), inactivity, loss of strength, and,
habitual guarding postures, which in turn set the stage for overuse,
and so on, in increments. That is why we call these MSDs
``cumulative trauma disorders''. My work on the pathogenesis of the
tennis elbow measured the impact of these physiological changes,
i.e., increased internal workload or muscle resistance due to
reduced tissue elasticity leading to electromyographically
detectable recruitment of ever more muscle fibers for the same
amount of external workload (which was held constant in these
electromyographic studies of isometric muscle action). This
increased recruitment of more muscle fibers makes the patient more
vulnerable to overexertion at even lower levels of external physical
demands * * * until the patient is unable to even lift a cup. [Ex.
37-15]
In a chapter of the Textbook of Clinical Occupational and Environmental
Medicine (1994, Ex. 38-440), Dr. Martin Cherniak described the symptoms
and disabling nature of epicondylitis:
The characteristic symptoms are pain with lifting , gripping,
and wrist extension.* * * Because grip and extension are so central
to many jobs, lateral epicondylitis is a condition that can be
irreconcilably chronic and produce major and undesirable changes in
life and work, despite its seeming mundane nature. [Ex. 38-440, pp.
384-385]
Epidemiological Evidence
NIOSH reviewed 18 cross-sectional studies and one cohort study that
addressed workplace risk factors and elbow MSDs. Table V-3 summarizes
some key aspects of these investigations, such as the occupations
examined, the biomechanical risk factors to which workers were exposed,
whether exposures were directly observed or measured during the study,
and whether the health outcomes were verified by trained medical
personnel during physical examination. Most of the studies compared the
prevalence of epicondylitis in workers with jobs known to have highly
repetitive, forceful tasks (e.g. meat and fish processing) to those
engaged in less repetitive, forceful work (e.g. office workers). In
some cases, the work also involved awkward hand and wrist postures. In
almost all the studies, workers were concurrently exposed to a
combination of 2 or 3 factors. One study specifically examined
vibration from the use of chain saws. Eleven of the studies based case
definition on physical examination and worker exposure on observational
analysis. Diagnosis of epicondylitis was consistent across studies and
required the presence of pain on palpation of the epicondylar area and
pain at the elbow upon resisted movement of the wrist. The existence of
work-related risk factors was generally made based on job/task
observation. Some studies videotaped job tasks and estimated cycle
times, static loading on the forearm, and wrist posture in order to
qualitatively group workers by exposure intensity. Other studies more
subjectively evaluated risk factor exposure by job observation alone.
Seven cross-sectional studies reviewed by NIOSH relied strictly on
self-reports of symptoms or exposure; OSHA considers these
investigations to be less reliable.
Table V-3.--Summary of Epidemiology Studies Examining Epicondylitis
----------------------------------------------------------------------------------------------------------------
Job type Physical Physical Risk Measure (95%
Study studied factors Exposure basis exam CI) \1\
----------------------------------------------------------------------------------------------------------------
Hughes (1997) Ex. 26-907.... Aluminum F/R?/P Checklist...... Yes......... OR=37*
smelter. (3-470)
Roquelaure (1996) Ex. 500-41- Manufacturing.. F/R/P Checklist...... Yes......... OR=7.7-18.0*
111. (2.2-147)
Kurppa (1991) Ex. 26-53..... Meat processing F/R/P? Observation.... Yes......... IR=6.7*
(3.3-13.9)
Chiang (1993) Ex. 26-1117... Fish processing F/R/P? Cycle time EMG. Yes......... OR=1.2-6.7*
(1.6-32.7)
Moore (1994) Ex. 26-1364.... Meat processing F/R/P Measurement.... Yes......... OR=5.5*
(1.5-62)
Bovenzi (1991) Ex. 26-1433.. Forestry....... V Measurement.... Yes......... OR=4.9*
(1.3-56)
SHARP (1993) Ex. 500-41-116. Poultry F/R/P? Measurement.... Yes......... NR*
processing. (p0.002)
Dimberg (1987) Ex. 26-945... Automotive..... F/R/P Observation.... Yes......... NR*
Dimberg (1989) Ex. 26-1211.. Automotive..... F/R/P Observation.... Yes......... NR
Ritz (1995) Ex. 26-1473..... Utilities...... F/R?/P? Observation.... Yes......... OR=1.2-1.7*
(1.0-2.7)
Luopajarvi (1979) Ex. 26-56. Food production F/R/P Measurement.... Yes......... OR=2.7
(0.7-15.9)
Baron (1991) Ex. 26-697..... Grocery F/R/P Measurement.... Yes......... OR=2.3
checking. (0.5-11)
Viikari-Juntura (1991) Ex. Meat processing F/R/P? Observation.... Yes......... OR=0.88
26-1197. (0.3-2.8)
[[Page 68456]]
Roto (1984) Ex. 26-666...... Meat cutting... F/R/P? Job title...... Yes......... OR=6.4*
(1.0-41)
Hoekstra (1994) Ex. 26-725.. Video terminal. R/P Observation.... No.......... OR=4.0*
(1.2-13)
Burt (1990) Ex. 26-698...... Computer entry. R/P Job title...... No.......... OR=2.8*) Ex. 26-1.4-
5.7)
Punnett (1985) Ex. 26-995... Garment........ R/P? Job title...... No.......... OR=2.4*
(1.2-4.2)
Ohlsson (1989) Ex. 26-1290.. Assembly line.. F?/R/P? Job title...... No.......... OR=1.5-2.8
(0.8-10.7)
Andersen (1993) Ex. 26-1451. Sewing machine. F/R/P? Observation.... No.......... OR=1.7
(0.9-3.3)
McCormack (1990) Ex. 26-1334 Textile........ F/R/P? Job title...... Yes......... OR=0.5-1.2
(0.5-3.4)
Bystrom (1995) Ex. 26-897... Auto assembly.. F/R/P Job title...... Yes......... OR=0.7
(0.04-1.7)
----------------------------------------------------------------------------------------------------------------
F=forceful exertions; R=repetitive motion; P=awkward posture; ?=presence of risk factor unclear.
IR=incidence rate; OR=odds ratio; NR=not reported.
*=p0.05.
\1\ 95% confidence interval expressed for the upper end of the risk measure range.
Seven of the 11 studies that relied on objective exposure
assessments and medical confirmation of epicondylitis found
statistically significant associations between exposure to work-related
risk factors and risk of epicondylitis. The most reliable odds ratios
(ORs) ranged between 1.0 to 5.5. Some studies deserve special mention.
One study was able to divide fish processing workers into a low-force/
low-repetition group, a high-force or high-repetition group, and a
high-force and high-repetition group based on observed cycle times and
hand forces from electromyography (EMG) recordings of the forearm
flexor muscles (Chiang et al.1993, Ex. 26-1117). An increasing trend
was found in prevalence of epicondylitis with increased exposure
intensity (not statistically significant). There was a significant
difference between males in the highest exposed group and males in the
lowest exposed group (OR=6.75; 95% CI 1.6-32.7), but this trend was not
observed among female workers (OR=1.4; 95% CI 0.3-5.6). A prospective
cohort study grouped meat processing workers into those engaged in
strenuous (primarily cutters and packers) and non-strenuous work
(primarily office work) based on repetitive and forceful tasks (Kurppa
et al. 1991, Ex. 26-53). They reported a significantly increased
incidence ratio (6.7; 95% CI 3.3-13.9) of epicondylitis among workers
in strenuous jobs over the 31-month follow-up period. Because of the
prospective study design, this study provided direct evidence of a
temporal relationship between exposure to biomechanical risk factors
and the increased incidence of epicondylitis.
One study evaluated vibration as a risk factor for epicondylitis
and reported a significantly greater prevalence of epicondylitis (OR =
4.9; 95% CI 1.3-56) in forestry operators using chain saws compared to
a comparison group of maintenance workers (Bovenzi et al.1991, Ex. 26-
1433).
Evidence of exposure-response trends in the epicondylitis
literature is limited because of the preponderance of studies that
relied on dichotomous comparisons of exposed versus unexposed workers;
however, one study found an increase (not statistically significant) in
prevalence with the number of hours per week working as a grocery
checker (Baron et al.1991, Ex. 26-697). Another reported a positive
(not statistically significant) exposure-response relationship between
duration of exposure to gas and waterworks jobs regarded as stressful
to the elbow (Ritz 1995, Ex. 26-1473).
Some unusually high ORs that were reported by a few studies and
contained in the NIOSH (1997, Ex. 26-1) review may have been overstated
due to bias. For example, one study of aluminum workers reported an OR
of 37 between elbow/forearm disorders and the number of years of
forearm twisting; however, the overall participation rate in the study
was only 55 percent, leaving open the possibility of selection bias
(Hughs and Silverstein 1997, Ex. 26-53). The cohort study by Kurppa et
al.(1991, Ex. 26-53) reported an epicondylitis incidence rate (IR) of
6.7 for workers performing strenuous tasks but counted recurrences in
the same elbow as if they were new cases. Reanalysis by NIOSH placed
the IR at 5.5 among workers with strenuous jobs versus those with non-
strenuous jobs after correcting for recurrent cases.
A few studies reported ORs between 1-3 that were not statistically
significant (Baron et al.1991, Ex. 26-697; Luopajarvi et al.1979, Ex.
26-56). The low risk ratios reported in these studies may reflect the
likelihood that the occupations studied (grocery checkers and assembly
line food packers) were associated with relatively low forces directed
to the forearm extensors combined with insufficient repetitiveness, as
compared to other jobs that involve higher forces and more repetition,
such as meat cutters/packers where higher prevalence rates of
epicondylitis have been found (Moore and Garg 1994, Ex. 26-1364). In
addition, cross-sectional studies are often subject to the ``healthy
worker'' effect because of the exclusion of injured workers who may
have left the workforce at the time a study was conducted. This can
sometimes lead to an underestimation of prevalence.
Most studies adequately controlled for the important confounder of
age but the contribution of non-occupational injury to the elbow was
often not addressed among groups of workers. The large number of
studies reporting a positive association with exposure make it unlikely
that non-occupational injuries were an important confounder. Dr.
Cherniak emphasized the importance of work rather than non-work
activities in the etiology of epicondylitis: ``Its popular epithet of
tennis elbow notwithstanding, it is a common condition among industrial
workers and
[[Page 68457]]
is not so common among players of racquet sports.'' [Ex. 38-440, p.
384]
NIOSH concluded that there was some evidence of an association
between exposure to force and epicondylitis based on the existence of
several studies with quantitative measures of load on the hand/forearm
that showed strong ORs (>5) for this risk factor (Moore and Garg 1994,
Ex. 26-1364; Chiang et al.1993, Ex. 26-1117). NIOSH concluded there was
insufficient evidence of an association between epicondylitis and
repetition or awkward posture alone based on an inadequate number of
studies that examined these risk factors as the dominant exposure
factor, particularly in any quantitative fashion. However, it is clear
that, in many of the epidmiological studies of epicondylitis,
repetition and, in some cases awkward posture, accompanied exposure to
force (see Table V-3).
Two additional epidemiological studies that address physical work
factors and elbow disorders were submitted to the OSHA docket following
publication of the proposal (Roquelaure et al.1996, Ex. 500-41-111;
SHARP 1993, Ex. 500-41-116), which are summarized below and included in
Table V-3. Both studies followed an adequate study design, directly
observed or measured exposure to workers, and used physical exam to
verify the MSD. OSHA, therefore, finds that the studies add
substantially to the evidence that the combination of forceful
exertion, repetitive motion, and awkward posture increase risk of
injury to the elbow.
The Safety and Health Assessment and Research Program (SHARP) of
the Washington State Department of Labor and Industries (1993, Ex. 500-
41-116) conducted a cross-sectional study of 104 poultry processing
workers. Epicondylitis was assessed by interview and physical
examination. Exposure was assessed by a risk factor checklist that
evaluated repetitiveness, forcefulness, mechanical stress, and wrist
deviation. The study found the prevalence of upper extremity MSD by
interview was 25% and by physical exam and interview was 17%. The
number of repetitive exertions per hour was significantly predictive of
epicondylitis (p=0.002).
Roquelaure et al.(1996, Ex 500-41-111) reported that work
characteristics of greater than 1 kg of hand force, less than 30-second
cycle times, and static hand work in workers were associated with
radial tunnel syndrome (RTS). RTS is a disorder in which the radial
nerve becomes compressed near the elbow causing pain and tenderness,
similar to epicondylitis. Roquelaure used a case-referent study of 21
RTS cases and 21 controls while studying 2,250 television, shoe, and
brake manufacturing workers. Participation rate was not reported.
Referents were age-, gender-, and plant-matched workers selected at
random from the same manufacturing population who had no upper limb
disorder for the previous eight years. Exposure was determined by
direct observation of two trained assessors using a checklist. RTS was
determined by reviewing the past two years of medical files of the
2,250 manufacturing workers. A case of RTS was defined as local
tenderness 4-5 cm distal to lateral epicondyle, pain in forearm
indirectly induced by supination, no peresis or muscle weakness and
positive EMG and nerve conduction studies. For 1 kg or greater of hand
force, an odds ratio of 18.0 (CI: 2.2-147.5, p=0.01) was reported
compared to those cases exposed to less hand force. For workers with
less than 30-second cycle times, an odds ratio of 8.7 (CI: 1.2-23.8,
p=0.03) was reported compared to those who had longer cycle times. For
workers with static hand work, an odds ratio of 7.7 (CI: 1.4-42.7,
p=0.02) was reported compared to those involved in more dynamic work.
This study demonstrates that an increased risk of RTS is associated
with exposure to force, repetition and static posture of the hand.
Two medical experts supplied written testimony on behalf of UPS
indicating that epidemiological evidence to support an association
between combined biomechanical factors (e.g. force, repetition, awkward
posture) and the different types of tendinitis of the upper extremities
(e.g. elbow (epicondylitis), hand/wrist (tenosynovitis)) likely are
flawed because of imprecise case definition. Dr. Peter Nathan wrote:
There is a startling lack of objective evidence to indicate that
actual pathology is involved in many of the soft tissue discomfort
complaints that are included under the umbrella of cumulative trauma
disorders or musculoskeletal disorders--a primary focus of the
ergonomic standard. * * * Dr. Armstrong refers to a Finnish study by
Luopajarvi et al.(1979, Ex. 26-56) which is one of three valid
studies referenced by Dr. Susan Stock in her 1991 meta-analysis of
the literature relating work exposure to conditions of the neck and
upper extremities. The variable representing tendinitis used by
Luopajarvi and his colleagues was primarily symptoms confirmed by
physical examination. This does not correspond to the classic
medical definition of tendinitis, which requires objective evidence
of true inflammation (Ex. 500-118).
Similarly, Dr. Nortin Hadler stated in written testimony:
The health effect in this paper [Kurppa et. al. 1991, Ex. 26-53]
is a sick leave consequent to regional disorders of the elbow or
wrist/hand. The investigators devised their nosology to capture
discomfort about the elbow and distal arm/hand. Essentially, all
they are describing is localized soreness and/or tenderness. The
criterion of swelling or crepitation and tenderness to palpation
along the tendon and pain at the tendon sheath, in the peritendinous
area, or the muscle/tendon junction during active movement of the
tendon boils down to focal soreness/tenderness and nothing more
specific or mysterious than that (Ex. 500-118).
These comments suggest that the two epidemiological studies cited above
exclusively rely on a collection of subjective symptoms indicative of
non-specific soreness and discomfort, rather than objective measurement
of inflammation and tissue pathology. This criticism also applies to
virtually all the existing epidemiological studies that examined
epicondylitis since they used a similar set of criteria to diagnose
this MSD. As a result, the commenters believe OSHA has not made a
sufficient case that true epicondylitis (as well as tenosynovitis) is
associated with workplace exposure to biomechanical risk factors.
OSHA disagrees with the notion that evidence of tissue pathology
among exposed workers is required to infer a causal relationship
between exposure to physical risk factors in the workplace and
epicondylitis. The studies of Luopajarvi et al.(Ex. 26-56) and Kurppa
et al.(Ex. 26-53) were directed by the Institute of Occupational Health
in Helsinki, Finland, which developed systematic methods for screening
and diagnosing a number of occupational neck, shoulder, and upper limb
disorders, including lateral and medial epicondylitis. The examination
procedures and diagnostic criteria have been published in the peer-
reviewed literature (Waris et al.1979, Ex. 26-1218) and they were
devised by a team of clinicians comprised of occupational physicians,
an orthopedist, physiologist, and ergonomist. The diagnosis for lateral
epicondylitis (the most common form of epicondylitis) is not simply
self-reported elbow soreness. The tenderness must be localized over the
lateral epicondyle and there must be pain associated with resisted
extension of the wrist and fingers (resistence test). In the Finnish
studies, these signs were evaluated by either physicians specializing
in occupational health or a trained physiotherapist. Other potential
causes unrelated to physical work factors, such as fractures, acute
trauma, recreational injuries, infection, arthritis, pre-existing
neurological diseases, etc., were assessed and screened out through
[[Page 68458]]
medical histories and personal interview.
The Finnish criteria are consistent with procedures for the
assessment, diagnosis, and management of elbow complaints recommended
by the American College of Occupational and Environmental Medicine
(ACOEM, Ex. 502-240). These guidelines do not call for tissue evidence
of inflammation and pathology in diagnosing lateral epicondylitis, but
rather depend on expert evaluation of unique signs and symptoms by a
trained clinician upon physical examination. The food packers in the
cross-sectional investigation by Luopajarvi et al. (Ex. 26-56) were
examined by a physiotherapist specially trained at the Finnish
Institute of Occupational Health. The meat processors in the
prospective Kurppa et al.(Ex. 26-53) study were primarily diagnosed by
occupational physicians at the plant using the criteria developed by
the Finnish Institute. The same diagnostic approach was also used by
the other key epidemiological studies that found an association between
work-related factors and epicondylitis (Chiang et al.1993, Ex. 26-1117;
Moore and Garg 1994, Ex. 26-1364; Bovenzi et al.1991, Ex. 26-1433).
More specialized diagnostic tools, such as imaging and
electromyography, are only advised if a prudent course of elbow/forearm
rest and pain relief do not adequately correct the disorder or more
serious complications are suspected (e.g. fracture, osteomyelitis,
neurological damage).
OSHA finds that the case definition of epicondylitis used by the
epidemiological investigators is appropriate for diagnosing this MSD.
The evaluations were administered by trained clinicians using specific
and standardized criteria that are uniformly accepted by the medical
community. This was confirmed by testimony from numerous physicians
during the hearings (AFL-CIO, Ex. 500-218). The published clinical
guidelines and testimony from the record cited above make clear that
the criteria of localized tenderness at a critical bone-tendon junction
(MSD symptom) combined with pain upon palpation and extension/flexion
of the wrist during physical examination (positive physical finding)
are sufficient for the proper diagnosis of epicondylitis without the
need for further ``objective evidence of true inflammation.''
Biomechanical Evidence
There is a very limited amount of specific study information
available in the Health Effects Appendices for the proposed rule (Ex.
27-1) that measure the biomechanical forces at the muscle-tendon units
of the elbow. However, as discussed in the Health Effects Appendix,
there is some evidence suggesting that tensile loading on the extensor
carpi radialis brevis (ECRB) muscle created by muscular action in
combination with elbow extension and pronation/supination of the
forearm causes a compressive force at the tendon, ligament, and radial
head of the elbow. Prolonged contact pressure and/or repeated loading
is likely to produce fraying of the ECRB. The resulting cycle of
damage/repair leads to clinical and pathological manifestations of
lateral epicondylitis.
Conclusion
The 1997 NIOSH report concluded the following with regard to the
relationship between work-related physical risk factors and
epicondylitis:
There is strong evidence for a relationship between exposure to
a combination of risk factors (e.g. force and repetition, force and
posture) and epicondylitis. Based on a review of the epidemiologic
studies, especially those with some quantitative evaluation of the
risk factors, the evidence is clear that an exposure to a
combination of exposures, especially at higher levels (as can be
seen in, for example, meatpacking or construction work) increases
the risk for epicondylitis (Ex. 26-1, Emphasis in original).
OSHA agrees with NIOSH that there is a reasonably strong body of
evidence showing a relationship between exposure to combinations of
biomechanical risk factors, usually forceful exertion/repetitive motion
or forceful exertion/repetitive motion/awkward posture, and an
increased risk of epicondylitis. This evidence emanates from the
consistently positive associations in epidemiological studies of
workers from several different industry sectors, especially those
investigations that rely on expert verification of injury and objective
determination of exposure. The epidemiological evidence is supported by
the large number of clinical reports and investigations in the medical
and sports literature. There is biological plausibility that exposure
to combinations of risk factors can lead to epicondylitis since
forceful and repetitive exertion of the forearm muscles and tendons are
also consistent with the pathophysiology of epicondylitis. As described
in the NIOSH review of the epidemiological evidence, there is less
evidence that exposure to repetition or awkward posture alone, is
associated with an increased risk of epicondylitis. OSHA concludes that
workers who perform job tasks requiring repeated forceful movements,
especially flexion, pronation, or supination with the arm extended, are
at increased risk of developing epicondylitis.
Tendinitis of the Hand and Wrist
Most cases of tendinitis of the hand and wrist originate as
inflammation of the synovial sheath that provides protection for the
tendons. This condition is known as tenosynovitis. Inflammation may
occur in the flexor tendons on the palmar aspect of the wrist, extensor
tendons on the back of the wrist, or the small separate collection of
extensor tendons that controls the extension of the thumb. There are a
number of pathophysiological outcomes that result from irritation of
the tendons. If the sheath becomes aggravated, excessive synovial fluid
can build up resulting in swelling along the affected tendon. Sometimes
irritation can occur just proximal to the tendon sheath where there is
no synovial fluid. This causes a dry rubbing of the tendon called
peritendinitis crepitans, so named because of the discernable creaking
sensation. There is also a type of tenosynovitis, known as stenosing
tenovanginitis, caused by a constriction of the tendons at the mouth of
the sheath. If this constriction occurs on the radial aspect of the
wrist involving the extensor tendons to the thumb, it is known as De
Quervain's syndrome. If the site of injury is the flexor tendons to the
fingers, it is known as trigger finger. Stenosing tenovanginitis is
thought to be the result of compression caused by the thickening of the
retinaculum (band of ligaments around the wrist holding the tendons in
place) leading to tendon entrapment.
One publication in the record described the symptoms and prognosis
of patients that have trigger finger or thumb:
The classic picture [of trigger finger/thumb patients] is
painful ``locking'' of the digit in flexion whereby the patient has
difficulty extending the proximal interphalangeal joint. Extension
can be accomplished passively using the other hand and produces a
moderate amount of discomfort and a palpable painful ``snap.'' * * *
The prognosis is excellent for a complete recovery barring the
occurrence of multiple trigger fingers and/or significant
osteoarthritis * * *. In these cases the course is usually
prolonged. Patients tend to question their ability to return to
their old jobs and, on occasion, any job. In general, workers should
be able to return to heavy work, although it may take somewhat
longer after surgery because of a tender palmar scar. [Ex. 38-453,
pp. 105-106]
[[Page 68459]]
Epidemiological Evidence
NIOSH (1997, Ex. 26-1) reviewed seven cross-sectional studies and
one cohort study that addressed workplace risk factors and MSDs that
specifically addressed hand/wrist tendinitis. Table V-4 summarizes some
key aspects of these investigations. In these studies, tendinitis cases
were identified primarily by physical examination, which usually
included localized pain/tenderness at the tendons upon palpation during
movement of the hand/wrist. However, diagnostic criteria varied across
studies depending on the types of tenosynovitis of interest. For
example, some investigations required the presence of swelling along
the tendons of the wrist and/or signs of crepitation. In some cases, a
positive Finkelstein's test was used to diagnose DeQuervain's syndrome.
Because of the differences in case definition, it is difficult to
compare prevalence rates from different studies, although measures of
relative risk should be less affected as long as case definitions were
non-differentially applied to exposed and unexposed groups (NIOSH 1997,
Ex. 26-1).
Exposure assessment was generally restricted to grouping workers in
exposed and unexposed categories based on the existence of a
combination of excessive force, repetitive motion, and awkward posture.
In these studies, most exposed workers were subjected to the combined
effect of at least two risk factors. Five studies relied on direct
observation of job tasks and expert judgment to determine exposure
(Armstrong et. al. 1987, Ex. 26-48; Luopajarvi et. al. 1979, Ex. 26-56;
Bystrom et. al. 1995, Ex. 26-897; Kuorinka et. al. 1979, Ex. 26-639;
Kurppa et. al. 1991, Ex. 26-53). One of these studies quantified force
and repetitiveness for a subset of workers performing different jobs
and grouped them according to these measurements (Armstrong et. al.
1987, Ex. 26-48). Three studies used less reliable methods of assessing
exposure such as self-reports or general knowledge of job tasks.
Table V-4.--Summary of Epidemiology Studies Examining Hand/Wrist Tendinitis
----------------------------------------------------------------------------------------------------------------
Job type Physical Physical Risk measure (95%
Study studied factors Exposure basis exam CI)\1\
----------------------------------------------------------------------------------------------------------------
Kurppa (1991) Ex. 26-53..... Meat processing F/R/P? Observation.... Yes......... IR=14-38.5*
(11-56)
Armstrong (1987) Ex. 26-48.. Manufacturing.. F/R/P? Measurement EMG Yes......... PRR=4.8-17*
(2.3-126)
Moore (2000) Ex. 500-71-41.. Pork processing F/R?P Observation.... Yes......... PRR=7.0*
F/R?/P.
Luopajarvi (1979) Ex. 26-56. Food production F/R/P Observation.... Yes......... PRR=4.1*
(2.6-6.5)
Latko (1999) Ex. 38-123..... Manufacturing.. R/F/P? Measurement, Yes......... OR=3.2*
cycle time. (1.3-8.3)
Bystrom (1995) Ex. 26-897... Auto assembly.. F/R/P Forearm load, Yes......... PRR=2.5*
wrist flex. (1.0-6.2)
Kuorinka (1979) Ex. 26-639.. Scissor F?/R/P Cycle time, Yes......... PRR=1.4
production. wrist flex. (0.8-2.5)
Amano (1988) Cited in Ex. 26- Shoe assembly.. F?/R/P Job title...... Yes......... PRR=3.7-6.2*
1. (2.7-14)
Roto (1984) Ex. 26-666...... Meat cutting... F/R/P? Job title...... Yes......... PRR=3.1*
(1.4-6.7)
McCormack (1990) Ex. 26-1334 Textile........ F/R/P? Job title...... Yes......... PRR=0.4-3.0*
(1.4-6.4)
----------------------------------------------------------------------------------------------------------------
F=forceful exertions; R=repetitive motion; P=awkward posture; ?=presence of risk factor unclear.
IR=incidence rate; PRR=prevalence ratios;
*=p0.05.
\1\ 95% confidence interval expressed for the upper end of the risk measure range.
Of the five studies with the most reliably documented exposure,
four reported statistically significant increases in the prevalence of
hand/wrist tendinitis in workers exposed to physical risk factors
(Armstrong et al.1987, Ex. 26-48; Luopajarvi et al.1979, Ex. 26-56;
Bystrom et al.1995, Ex. 26-897; Kurppa et al.1991, Ex.26-53). In their
review, NIOSH (1997, Ex. 27-1) chose the prevalence ratio (PR) to
represent an estimate of relative risk rather than the more commonly
reported OR for hand/wrist tendinitis, because the OR can overestimate
relative risk when prevalence rates among unexposed groups are high. A
few of the studies on work-related tendinitis reported prevalence rates
greater than 25 percent in exposed groups and greater than 10 percent
in unexposed groups.
The Armstrong et al.(Ex. 26-48) study was able to divide industrial
workers at seven manufacturing plants into a low force/low repetition
group, a high force/low repetition group, low force/high repetition
group, and a high force/high repetition group based on EMG measurements
and observed cycle times. They found exposure-related increases in the
prevalence of tenosynovitis (including stenosing tenovanginitis). The
high-force/low-repetition group and low-force/high-repetition group had
PRs of 4.8 (95% CI 0.6-39.7) and 5.5 (95% CI 0.7-46.3), respectively,
compared to the low-force/low-repetition group, while the high-force/
high-repetition group had a PR of 17.0 (2.3-126.2). The Kourinka et
al.(Ex. 26-639) study of mostly female scissors makers found a non-
statistically significant increase in the prevalence of tenosynovitis
(including peritendinitis) with an increase in the number of pieces
handled per year. The PR was 1.4 (95% CI 0.8-2.5) among all exposed
workers compared to a referent group of department store assistants. In
this study, it is unclear whether cashiers (a potentially exposed
group) were included in the referent population; if so, this would tend
to diminish the association between exposure and outcome. The results
of these two studies suggest the presence of a positive exposure-
response relationship between exposure to biomechanical risk
[[Page 68460]]
factors and the risk of hand/wrist tendinitis.
Luopajarvi et al.(Ex. 26-56) found a significant increase in PR
(4.1; 95% CI 2.6-6.5) of tenosynovitis (including peritendinitis) among
female assembly line food packers compared to department store
assistants (cashiers excluded from the unexposed group). Bystrom et
al.(Ex. 26-897) found a significant increase in PR (2.5; 95% CI 1.0-
6.2) of DeQuervain's syndrome among automobile assembly line workers
compared to randomly selected subjects (adjusted for potential
confounders) from the general population. The prospective cohort study
by Kurppa et al.(Ex. 26-53) found a significant increase in the
incidence of tenosynovitis (including peritendinitis and DeQuervain's
syndrome) over a 31-month period in meat processing workers (primarily
cutters and packers) engaged in strenuous compared to non-strenuous
work (primarily office work). They reported relative risks ranging from
14.0 to 38.5 for different job categories, but these may be
overestimated since recurrences of tendinitis were counted as new cases
and case ascertainment was different for the exposed and referent
groups. This study does provide evidence of a temporal relationship
between exposure to physical work factors and development of
tendinitis. Confounders, such as gender and age, were adequately
controlled for in the key studies.
Two studies that address physical work factors and tenosynovitis
were submitted to the OSHA docket following publication of the proposal
(Moore 2000, Ex. 26-1364; Latko et al.1999, Ex. 38-123). Summary
results of these studies also appear in Table V-4. Moore (Ex. 500-71-
41) found a significant increase in the prevalence of stenosing
tenovanginitis as a result of jobs requiring repetitive and forceful
use of hand tools compared to jobs without exposure to this risk
factor. Latko et al.(Ex. 38-123) reported a significant linear trend
between repetitive work and hand/wrist tendinitis (p0.01) in a cross-
sectional study of 438 manufacturing workers. Worker exposure to
physical work factors were directly observed and measured in this study
and tendinitis cases were confirmed through physical examination by an
occupational physician in both the Moore and Latko studies.
Biomechanical Evidence
Static and dynamic biomechanical models of the wrist have been used
to estimate tensile, normal, and frictional forces in finger flexor
tendons during static and dynamic work involving the hand (Exs. 26-582,
38-418). Pinching and gripping activities produce tensile forces on the
tendons that are three to four times the normal force on the fingers.
Static biomechanical models predict that additional compressive and
frictional forces are exerted on the tendon when the wrist deviates
from a neutral position as the tendon sheaths slide against the bones
of the carpal tunnel and flexor retinaculum. These predictions have
been confirmed by cadaver studies of forces on the tendons, ligaments,
and bones of the hand. A laboratory study showed that peak tensile
forces in the flexor tendons were approximately doubled during a
simulated caulking task with a straight wrist and approximately tripled
during the same task with a flexed wrist (Moore et al.1991, Ex. 26-
183).
When a dynamic component is added to the biomechanical model, it is
predicted that tensile and normal forces on the finger flexor tendons
increase rapidly during rapid wrist accelerations. These predictions
are supported by a preliminary surveillance study that found wrist
acceleration to be substantially higher in jobs with a high rate of
upper extremity cumulative trauma disorders (Marras and Shoenmarklin
1993, Ex. 26-172). The biomechanical and laboratory evidence provides
additional support that biomechanical risk factors, such as sustained/
repetitive forceful exertions and flexion/extension of the wrist, can
create internal strain on tendons that could result in injury
consistent with tenosynovitis.
Conclusion
The 1997 NIOSH report concluded the following with regard to the
relationship between work-related physical risk factors and hand/wrist
tendinitis: ``There is strong evidence that job tasks that require a
combination of risk factors (e.g., highly repetitious, forceful hand/
wrist exertions) increase risk for hand/wrist tendinitis'' (Ex. 26-1).
OSHA also finds clear epidemiologic evidence of a relationship between
a combination of physical risk factors, such as repetitive and forceful
hand activities with a flexed wrist, and tenosynovitis. This evidence
is from the consistently positive associations in the epidemiological
studies described above. There are also laboratory studies that confirm
that hand-intensive work, particularly with a bent wrist, produces
significant load and strain on the flexor tendons. The biomechanical
evidence is consistent with the pathophysiology of tenosynovitis where
sustained and elevated internal force on the tendon sheaths can be
expected to cause synovial fluid accumulation, thickening of the
sheath, tendon entrapment, and other physiological responses that lead
to clinical symptoms associated with this MSD. These biomechanical
studies demonstrate that the increased risk of hand/wrist tendinitis
seen among workers exposed to forceful and repetitive hand activities
is biologically plausible and consistent with the epidemiologic
evidence. OSHA therefore concludes that workers exposed to these risk
factors are at increased risk of developing hand/wrist tendinitis.
Carpal Tunnel Syndrome (CTS)
CTS is a disorder that results from compression of the median nerve
at the point of passage through the carpal tunnel, the narrow opening
in the hand consisting of carpal bones of the wrist on the bottom and
the carpal ligament on top. The carpal tunnel is a relatively ``tight''
compartment filled with flexor tendons as well as the median nerve that
serve to move and enervate the fingers. Forceful contraction of the
flexor tendons in the fingers that occur during repetitive hand tasks
increase the pressure within the carpal tunnel (Ex. 38-444). Chronic
intracarpal pressure limits the vascular flow to the median nerve and
surrounding tissue leading to swelling of the tendon sheath. The
epineural edema leads to compression of the median nerve against the
carpal ligament. The ensuing loss of nerve function initially results
in painful tingling and numbness in the hand. After several years,
eventually the tendon tissue can become fibrotic and result in muscle
weakness, reduced grip strength and loss of finger movement. CTS is
often accompanied by tenosynovitis, which is not surprising given their
common pathophysiology. CTS is a disabling condition that has
frequently required surgery to provide the affected individual with
relief. For example, in Washington State in 1996, more than one-third
of all CTS workers' compensation claimants required surgery as part of
their treatment (Ex. 500-71-47, P. 12). Histologic studies of flexor
tendon sheaths sampled during carpal tunnel surgery support the above
model since vascular changes consistent with ischemia and tissue edema
are commonly observed (Ex. 26-838).
National and international surveillance data have consistently
indicated that the highest rates of CTS occur in occupations and job
tasks (meat processing, assembly line work, intensive use of hand and
power tools, etc.) requiring repeated wrist movements, forceful
exertions, and
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