[Code of Federal Regulations]
[Title 29, Volume 7]
[Revised as of July 1, 2005]
From the U.S. Government Printing Office via GPO Access
[CITE: 29CFR1915.1001]
[Page 119-196]
TITLE 29--LABOR
CHAPTER XVII--OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT
OF LABOR (CONTINUED)
PART 1915_OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD
EMPLOYMENT--Table of Contents
Subpart Z_Toxic and Hazardous Substances
Sec. 1915.1001 Asbestos.
(a) Scope and application. This section regulates asbestos exposure
in all shipyard employment work as defined in 29 CFR part 1915,
including but not limited to the following:
(1) Demolition or salvage of structures, vessels, and vessel
sections where asbestos is present;
(2) Removal or encapsulation of materials containing asbestos;
(3) Construction, alteration, repair, maintenance, or renovation of
vessels, vessel sections, structures, substrates, or portions thereof,
that contain asbestos;
(4) Installation of products containing asbestos;
(5) Asbestos spill/emergency cleanup; and
(6) Transportation, disposal, storage, containment of and
housekeeping activities involving asbestos or products containing
asbestos, on the site or location at which construction activities are
performed.
(7) Coverage under this standard shall be based on the nature of the
work operation involving asbestos exposure.
(8) This section does not apply to asbestos-containing asphalt roof
cements, coatings and mastics.
(b) Definitions.
Aggressive method means removal or disturbance of building/vessel
materials by sanding, abrading, grinding, or other method that breaks,
crumbles, or otherwise disintegrates intact ACM.
Amended water means water to which surfactant (wetting agent) has
been added to increase the ability of the liquid to penetrate ACM.
Asbestos includes chrysotile, amosite, crocidolite, tremolite
asbestos, anthophyllite asbestos, actinolite asbestos, and any of these
minerals that has been chemically treated and/or altered. For purposes
of this standard, asbestos includes PACM, as defined below.
Asbestos-containing material, (ACM) means any material containing
more than one percent asbestos.
Assistant Secretary means the Assistant Secretary of Labor for
Occupational Safety and Health, U.S. Department of Labor, or designee.
Authorized person means any person authorized by the employer and
required by work duties to be present in regulated areas.
Building/facility/vessel owner is the legal entity, including a
lessee, which exercises control over management and record keeping
functions relating to a building, facility, and/or vessel in which
activities covered by this standard take place.
Certified Industrial Hygienist (CIH) means one certified in the
practice of industrial hygiene by the American Board of Industrial
Hygiene.
Class I asbestos work means activities involving the removal of
thermal system insulation or surfacing ACM/PACM.
Class II asbestos work means activities involving the removal of ACM
which is neither TSI or surfacing ACM. This includes, but is not limited
to, the removal of asbestos-containing wallboard, floor tile and
sheeting, roofing and siding shingles, and construction mastics.
Class III asbestos work means repair and maintenance operations,
where ``ACM'', including TSI and surfacing ACM and PACM, is likely to be
disturbed.
Class IV asbestos work means maintenance and custodial activities
during which employees contact but do not disturb ACM or PACM and
activities to clean up dust, waste and debris resulting from Class I,
II, and III activities.
Clean room means an uncontaminated room having facilities for the
storage of employees' street clothing and uncontaminated materials and
equipment.
Closely resemble means that the major workplace conditions which
have contributed to the levels of historic asbestos exposure, are no
more protective than conditions of the current workplace.
Competent person see qualified person.
Critical barrier means one or more layers of plastic sealed over all
openings into a work area or any other physical barrier sufficient to
prevent airborne asbestos in a work area from migrating to an adjacent
area.
Decontamination area means an enclosed area adjacent and connected
to the regulated area and consisting of an
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equipment room, shower area, and clean room, which is used for the
decontamination of workers, materials, and equipment that are
contaminated with asbestos.
Demolition means the wrecking or taking out of any load-supporting
structural member and any related razing, removing, or stripping of
asbestos products.
Director means the Director, National Institute for Occupational
Safety and Health, U.S. Department of Health and Human Services, or
designee.
Disturbance means activities that disrupt the matrix of ACM or PACM,
crumble or pulverize ACM or PACM, or generate visible debris from ACM or
PACM. Disturbance includes cutting away small amounts of ACM and PACM,
no greater than the amount which can be contained in one standard sized
glove bag or waste bag, in order to access a building or vessel
component. In no event shall the amount of ACM or PACM so disturbed
exceed that which can be contained in one glove bag or waste bag which
shall not exceed 60 inches in length and width.
Employee exposure means that exposure to airborne asbestos that
would occur if the employee were not using respiratory protective
equipment.
Equipment room (change room) means a contaminated room located
within the decontamination area that is supplied with impermeable bags
or containers for the disposal of contaminated protective clothing and
equipment.
Fiber means a particulate form of asbestos, 5 micrometers or longer,
with a length-to-diameter ratio of at least 3 to 1.
Glovebag means not more than a 60x60 inch impervious plastic bag-
like enclosure affixed around an asbestos-containing material, with
glove-like appendages through which material and tools may be handled.
High-efficiency particulate air (HEPA) filter means a filter capable
of trapping and retaining at least 99.97 percent of all mono-dispersed
particles of 0.3 micrometers in diameter.
Homogeneous area means an area of surfacing material or thermal
system insulation that is uniform in color and texture.
Industrial hygienist means a professional qualified by education,
training, and experience to anticipate, recognize, evaluate and develop
controls for occupational health hazards.
Intact means that the ACM has not crumbled, been pulverized, or
otherwise deteriorated so that the asbestos is no longer likely to be
bound with its matrix.
Modification for purposes of paragraph (g)(6)(ii) of this section
means a changed or altered procedure, material or component of a control
system, which replaces a procedure, material or component of a required
system. Omitting a procedure or component, or reducing or diminishing
the stringency or strength of a material or component of the control
system is not a ``modification'' for purposes of paragraph (g)(6) of
this section.
Negative Initial Exposure Assessment means a demonstration by the
employer, which complies with the criteria in paragraph (f)(2)(iii) of
this section, that employee exposure during an operation is expected to
be consistently below the PELs.
PACM means presumed asbestos containing material.
Presumed asbestos containing material means thermal system
insulation and surfacing material found in buildings, vessels, and
vessel sections constructed no later than 1980. The designation of a
material as ``PACM'' may be rebutted pursuant to paragraph (k)(5) of
this section.
Project Designer means a person who has successfully completed the
training requirements for an abatement project designer established by
40 U.S.C. Sec. 763.90(g).
Qualified person means, in addition to the definition in 29 CFR
1926.32(f), one who is capable of identifying existing asbestos hazards
in the workplace and selecting the appropriate control strategy for
asbestos exposure, who has the authority to take prompt corrective
measures to eliminate them, as specified in 29 CFR 1926.32(f); in
addition, for Class I and Class II work who is specially trained in a
training course which meets the criteria of EPA's Model Accreditation
Plan (40 CFR part 763) for supervisor, or its equivalent, and for Class
III and Class IV work,
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who is trained in a manner consistent with EPA requirements for training
of local education agency maintenance and custodial staff as set forth
at 40 CFR 763.92(a)(2).
Regulated area means an area established by the employer to
demarcate areas where Class I, II, and III asbestos work is conducted,
and any adjoining area where debris and waste from such asbestos work
accumulate; and a work area within which airborne concentrations of
asbestos, exceed or can reasonably be expected to exceed the permissible
exposure limit. Requirements for regulated areas are set out in
paragraph (e) of this section.
Removal means all operations where ACM and/or PACM is taken out or
stripped from structures or substrates, and includes demolition
operations.
Renovation means the modifying of any existing vessel, vessel
section, structure, or portion thereof.
Repair means overhauling, rebuilding, reconstructing, or
reconditioning of vessels, vessel sections, structures or substrates,
including encapsulation or other repair of ACM or PACM attached to
structures or substrates.
Surfacing material means material that is sprayed, troweled-on or
otherwise applied to surfaces (such as acoustical plaster on ceilings
and fireproofing materials on structural members, or other materials on
surfaces for acoustical, fireproofing, and other purposes).
Surfacing ACM means surfacing material which contains more than 1%
asbestos.
Thermal system insulation (TSI) means ACM applied to pipes,
fittings, boilers, breeching, tanks, ducts or other structural
components to prevent heat loss or gain.
Thermal system insulation ACM is thermal system insulation which
contains more than 1% asbestos.
(c) Permissible exposure limits (PELS)--(1) Time-weighted average
limit (TWA). The employer shall ensure that no employee is exposed to an
airborne concentration of asbestos in excess of 0.1 fiber per cubic
centimeter of air as an eight (8) hour time-weighted average (TWA), as
determined by the method prescribed in appendix A to this section, or by
an equivalent method.
(2) Excursion limit. The employer shall ensure that no employee is
exposed to an airborne concentration of asbestos in excess of 1.0 fiber
per cubic centimeter of air (1 f/cc) as averaged over a sampling period
of thirty (30) minutes, as determined by the method prescribed in
appendix A to this section, or by an equivalent method.
(d) Multi-employer worksites. (1) On multi-employer worksites, an
employer performing work requiring the establishment of a regulated area
shall inform other employers on the site of the nature of the employer's
work with asbestos and/or PACM, of the existence of and requirements
pertaining to regulated areas, and the measures taken to ensure that
employees of such other employers are not exposed to asbestos.
(2) Asbestos hazards at a multi-employer worksite shall be abated by
the contractor who created or controls the source of asbestos
contamination. For example, if there is a significant breach of an
enclosure containing Class I work, the employer responsible for erecting
the enclosure shall repair the breach immediately.
(3) In addition, all employers of employees exposed to asbestos
hazards shall comply with applicable protective provisions to protect
their employees. For example, if employees working immediately adjacent
to a Class I asbestos job are exposed to asbestos due to the inadequate
containment of such job, their employer shall either remove the
employees from the area until the enclosure breach is repaired; or
perform an initial exposure assessment pursuant to paragraph (f) of this
section.
(4) All employers of employees working adjacent to regulated areas
established by another employer on a multi-employer worksite shall take
steps on a daily basis to ascertain the integrity of the enclosure and/
or the effectiveness of the control method relied on by the primary
asbestos contractor to assure that asbestos fibers do not migrate to
such adjacent areas.
(5) All general contractors on a shipyard project which includes
work covered by this standard shall be deemed to exercise general
supervisory authority over the work covered by this
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standard, even though the general contractor is not qualified to serve
as the asbestos ``qualified person'' as defined by paragraph (b) of this
section. As supervisor of the entire project, the general contractor
shall ascertain whether the asbestos contractor is in compliance with
this standard, and shall require such contractor to come into compliance
with this standard when necessary.
(e) Regulated areas. (1) All Class I, II and III asbestos work shall
be conducted within regulated areas. All other operations covered by
this standard shall be conducted within a regulated area where airborne
concentrations of asbestos exceed, or there is a reasonable possibility
they may exceed a PEL. Regulated areas shall comply with the
requirements of paragraphs (e) (2), (3), (4) and (5) of this section.
(2) Demarcation. The regulated area shall be demarcated in any
manner that minimizes the number of persons within the area and protects
persons outside the area from exposure to airborne asbestos. Where
critical barriers or negative pressure enclosures are used, they may
demarcate the regulated area. Signs shall be provided and displayed
pursuant to the requirements of paragraph (k)(7) of this section.
(3) Access. Access to regulated areas shall be limited to authorized
persons and to persons authorized by the Act or regulations issued
pursuant thereto.
(4) Respirators. All persons entering a regulated area where
employees are required pursuant to paragraph (h)(1) of this section to
wear respirators shall be supplied with a respirator selected in
accordance with paragraph (h)(2) of this section.
(5) Prohibited activities. The employer shall ensure that employees
do not eat, drink, smoke, chew tobacco or gum, or apply cosmetics in the
regulated area.
(6) Qualified persons. The employer shall ensure that all asbestos
work performed within regulated areas is supervised by a qualified
person, as defined in paragraph (b) of this section. The duties of the
qualified person are set out in paragraph (o) of this section.
(f) Exposure assessments and monitoring--(1) General monitoring
criteria. (i) Each employer who has a workplace or work operation where
exposure monitoring is required under this section shall perform
monitoring to determine accurately the airborne concentrations of
asbestos to which employees may be exposed.
(ii) Determinations of employee exposure shall be made from
breathing zone air samples that are representative of the 8-hour TWA and
30-minute short-term exposures of each employee.
(iii) Representative 8-hour TWA employee exposure shall be
determined on the basis of one or more samples representing full-shift
exposure for employees in each work area. Representative 30-minute
short-term employee exposures shall be determined on the basis of one or
more samples representing 30 minute exposures associated with operations
that are most likely to produce exposures above the excursion limit for
employees in each work area.
(2) Initial exposure assessment. (i) Each employer who has a
workplace or work operation covered by this standard shall ensure that a
``qualified person'' conducts an exposure assessment immediately before
or at the initiation of the operation to ascertain expected exposures
during that operation or workplace. The assessment must be completed in
time to comply with requirements which are triggered by exposure data or
the lack of a ``negative exposure assessment,'' and to provide
information necessary to assure that all control systems planned are
appropriate for that operation and will work properly.
(ii) Basis of initial exposure assessment. Unless a negative
exposure assessment has been made pursuant to paragraph (f)(2)(iii) of
this section, the initial exposure assessment shall, if feasible, be
based on monitoring conducted pursuant to paragraph (f)(1)(iii) of this
section. The assessment shall take into consideration both the
monitoring results and all observations, information or calculations
which indicate employee exposure to asbestos, including any previous
monitoring conducted in the workplace, or of the operations of the
employer which indicate the levels of airborne asbestos likely to be
encountered on the job. For Class I asbestos work, until the employer
conducts exposure monitoring and documents
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that employees on that job will not be exposed in excess of the PELs, or
otherwise makes a negative exposure assessment pursuant to paragraph
(f)(2)(iii) of this section, the employer shall presume that employees
are exposed in excess of the TWA and excursion limit.
(iii) Negative initial exposure assessment. For any one specific
asbestos job which will be performed by employees who have been trained
in compliance with the standard, the employer may demonstrate that
employee exposures will be below the PELs by data which conform to the
following criteria:
(A) Objective data demonstrating that the product or material
containing asbestos minerals or the activity involving such product or
material cannot release airborne fibers in concentrations exceeding the
TWA and excursion limit under those work conditions having the greatest
potential for releasing asbestos; or
(B) Where the employer has monitored prior asbestos jobs for the PEL
and the excursion limit within 12 months of the current or projected
job, the monitoring and analysis were performed in compliance with the
asbestos standard in effect; and the data were obtained during work
operations conducted under workplace conditions ``closely resembling''
the processes, type of material, control methods, work practices, and
environmental conditions used and prevailing in the employer's current
operations, the operations were conducted by employees whose training
and experience are no more extensive than that of employees performing
the current job, and these data show that under the conditions
prevailing and which will prevail in the current workplace there is a
high degree of certainty that employee exposures will not exceed the TWA
and excursion limit; or
(C) The results of initial exposure monitoring of the current job
made from breathing zone air samples that are representative of the 8-
hour TWA and 30-minute short-term exposures of each employee covering
operations which are most likely during the performance of the entire
asbestos job to result in exposures over the PELs.
(3) Periodic monitoring--(i) Class I and II operations. The employer
shall conduct daily monitoring that is representative of the exposure of
each employee who is assigned to work within a regulated area who is
performing Class I or II work, unless the employer pursuant to paragraph
(f)(2)(iii) of this section, has made a negative exposure assessment for
the entire operation.
(ii) All operations under the standard other than Class I and II
operations. The employer shall conduct periodic monitoring of all work
where exposures are expected to exceed a PEL, at intervals sufficient to
document the validity of the exposure prediction.
(iii) Exception. When all employees required to be monitored daily
are equipped with supplied-air respirators operated in the pressure
demand mode, or other positive pressure mode respirator, the employer
may dispense with the daily monitoring required by this paragraph.
However, employees performing Class I work using a control method which
is not listed in paragraph (g)(4) (i), (ii), or (iii) of this section or
using a modification of a listed control method, shall continue to be
monitored daily even if they are equipped with supplied-air respirators.
(4) Termination of monitoring. (i) If the periodic monitoring
required by paragraph (f)(3) of this section reveals that employee
exposures, as indicated by statistically reliable measurements, are
below the permissible exposure limit and excursion limit the employer
may discontinue monitoring for those employees whose exposures are
represented by such monitoring.
(ii) Additional monitoring. Notwithstanding the provisions of
paragraph (f) (2) and (3), and (f)(4) of this section, the employer
shall institute the exposure monitoring required under paragraph (f)(3)
of this section whenever there has been a change in process, control
equipment, personnel or work practices that may result in new or
additional exposures above the permissible exposure limit and/or
excursion limit or when the employer has any reason to suspect that a
change may result in new or additional exposures above the permissible
exposure limit and/or excursion limit. Such additional monitoring is
required regardless of whether
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a ``negative exposure assessment'' was previously produced for a
specific job.
(5) Employee notification of monitoring results. The employer must,
as soon as possible but no later than 5 days after the receipt of the
results of any monitoring performed under this section, notify each
affected employee of these results either individually in writing or by
posting the results in an appropriate location that is accessible to
employees.
(6) Observation of monitoring. (i) The employer shall provide
affected employees and their designated representatives an opportunity
to observe any monitoring of employee exposure to asbestos conducted in
accordance with this section.
(ii) When observation of the monitoring of employee exposure to
asbestos requires entry into an area where the use of protective
clothing or equipment is required, the observer shall be provided with
and be required to use such clothing and equipment and shall comply with
all other applicable safety and health procedures.
(g) Methods of compliance--(1) Engineering controls and work
practices for all operations covered by this section. The employer shall
use the following engineering controls and work practices in all
operations covered by this section, regardless of the levels of
exposure:
(i) Vacuum cleaners equipped with HEPA filters to collect all debris
and dust containing ACM and PACM, except as provided in paragraph
(g)(8)(ii) of this section in the case of roofing material;
(ii) Wet methods, or wetting agents, to control employee exposures
during asbestos handling, mixing, removal, cutting, application, and
cleanup, except where employers demonstrate that the use of wet methods
is infeasible due to for example, the creation of electrical hazards,
equipment malfunction, and, in roofing, except as provided in paragraph
(g)(8)(ii) of this section; and
(iii) Prompt clean-up and disposal of wastes and debris contaminated
with asbestos in leak-tight containers except in roofing operations,
where the procedures specified in paragraph (g)(8)(ii) of this section
apply.
(2) In addition to the requirements of paragraph (g)(1) of this
section above, the employer shall use the following control methods to
achieve compliance with the TWA permissible exposure limit and excursion
limit prescribed by paragraph (c) of this section;
(i) Local exhaust ventilation equipped with HEPA filter dust
collection systems;
(ii) Enclosure or isolation of processes producing asbestos dust;
(iii) Ventilation of the regulated area to move contaminated air
away from the breathing zone of employees and toward a filtration or
collection device equipped with a HEPA filter;
(iv) Use of other work practices and engineering controls that the
Assistant Secretary can show to be feasible.
(v) Wherever the feasible engineering and work practice controls
described above are not sufficient to reduce employee exposure to or
below the permissible exposure limit and/or excursion limit prescribed
in paragraph (c) of this section, the employer shall use them to reduce
employee exposure to the lowest levels attainable by these controls and
shall supplement them by the use of respiratory protection that complies
with the requirements of paragraph (h) of this section.
(3) Prohibitions. The following work practices and engineering
controls shall not be used for work related to asbestos or for work
which disturbs ACM or PACM, regardless of measured levels of asbestos
exposure or the results of initial exposure assessments:
(i) High-speed abrasive disc saws that are not equipped with point
of cut ventilator or enclosures with HEPA filtered exhaust air.
(ii) Compressed air used to remove asbestos, or materials containing
asbestos, unless the compressed air is used in conjunction with an
enclosed ventilation system designed to capture the dust cloud created
by the compressed air.
(iii) Dry sweeping, shoveling or other dry clean-up of dust and
debris containing ACM and PACM.
(iv) Employee rotation as a means of reducing employee exposure to
asbestos.
(4) Class I requirements. In addition to the provisions of
paragraphs (g) (1) and
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(2) of this section, the following engineering controls and work
practices and procedures shall be used.
(i) All Class I work, including the installation and operation of
the control system shall be supervised by a qualified person as defined
in paragraph (b) of this section;
(ii) For all Class I jobs involving the removal of more than 25
linear or 10 square feet of TSI or surfacing ACM or PACM; for all other
Class I jobs, where the employer cannot produce a negative exposure
assessment pursuant to paragraph (f)(2)(iii) of this section, or where
employees are working in areas adjacent to the regulated area, while the
Class I work is being performed, the employer shall use one of the
following methods to ensure that airborne asbestos does not migrate from
the regulated area:
(A) Critical barriers shall be placed over all the openings to the
regulated area, except where activities are performed outdoors; or
(B) The employer shall use another barrier or isolation method which
prevents the migration of airborne asbestos from the regulated area, as
verified by perimeter area surveillance during each work shift at each
boundary of the regulated area, showing no visible asbestos dust; and
perimeter area monitoring showing that clearance levels contained in 40
CFR part 763, subpart E of the EPA Asbestos in Schools Rule are met, or
that perimeter area levels, measured by Phase Contrast Microscopy (PCM)
are no more than background levels representing the same area before the
asbestos work began. The results of such monitoring shall be made known
to the employer no later than 24 hours from the end of the work shift
represented by such monitoring. Exception: For work completed outdoors
where employees are not working in areas adjacent to the regulated
areas, this paragraph (g)(4)(ii) is satisfied when the specific control
methods in paragraph (g)(5) of this section are used.
(iii) For all Class I jobs, HVAC systems shall be isolated in the
regulated area by sealing with a double layer of 6 mil plastic or the
equivalent;
(iv) For all Class I jobs, impermeable dropcloths shall be placed on
surfaces beneath all removal activity;
(v) For all Class I jobs, all objects within the regulated area
shall be covered with impermeable dropcloths or plastic sheeting which
is secured by duct tape or an equivalent.
(vi) For all Class I jobs where the employer cannot produce a
negative exposure assessment or where exposure monitoring shows the PELs
are exceeded, the employer shall ventilate the regulated area to move
contaminated air away from the breathing zone of employees toward a HEPA
filtration or collection device.
(5) Specific control systems for Class I work. In addition, Class I
asbestos work shall be performed using one or more of the following
control methods pursuant to the limitations stated below:
(i) Negative pressure enclosure (NPE) systems. NPE systems may be
used where the configuration of the work area does not make the erection
of the enclosure infeasible, with the following specifications and work
practices.
(A) Specifications--(1) The negative pressure enclosure (NPE) may be
of any configuration,
(2) At least 4 air changes per hour shall be maintained in the NPE,
(3) A minimum of -0.02 column inches of water pressure differential,
relative to outside pressure, shall be maintained within the NPE as
evidenced by manometric measurements,
(4) The NPE shall be kept under negative pressure throughout the
period of its use, and
(5) Air movement shall be directed away from employees performing
asbestos work within the enclosure, and toward a HEPA filtration or a
collection device.
(B) Work practices--(1) Before beginning work within the enclosure
and at the beginning of each shift, the NPE shall be inspected for
breaches and smoke-tested for leaks, and any leaks sealed.
(2) Electrical circuits in the enclosure shall be deactivated,
unless equipped with ground-fault circuit interrupters.
(ii) Glove bag systems may be used to remove PACM and/or ACM from
straight runs of piping and elbows and
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other connections with the following specifications and work practices:
(A) Specifications--(1) Glovebags shall be made of 6 mil thick
plastic and shall be seamless at the bottom.
(2) Glovebags used on elbows and other connections must be designed
for that purpose and used without modifications.
(B) Work practices--(1) Each glovebag shall be installed so that it
completely covers the circumference of pipes or other structures where
the work is to be done.
(2) Glovebags shall be smoke-tested for leaks and any leaks sealed
prior to use.
(3) Glovebags may be used only once and may not be moved.
(4) Glovebags shall not be used on surfaces whose temperature
exceeds 150 [deg]F.
(5) Prior to disposal, glovebags shall be collapsed by removing air
within them using a HEPA vacuum.
(6) Before beginning the operation, loose and friable material
adjacent to the glovebag/box operation shall be wrapped and sealed in
two layers of six mil plastic or otherwise rendered intact.
(7) Where a system uses an attached waste bag, such bag shall be
connected to a collection bag using hose or other material which shall
withstand the pressure of ACM waste and water without losing its
integrity.
(8) A sliding valve or other device shall separate the waste bag
from the hose to ensure no exposure when the waste bag is disconnected.
(9) At least two persons shall perform Class I glovebag removal
operations.
(iii) Negative pressure glove bag systems. Negative pressure glove
bag systems may be used to remove ACM or PACM from piping.
(A) Specifications: In addition to the specifications for glove bag
systems above, negative pressure glove bag systems shall attach the HEPA
vacuum system or other device to the bag to prevent collapse during
removal.
(B) Work practices--(1) The employer shall comply with the work
practices for glove bag systems in paragraph (g)(5)(ii)(B)(4) of this
section,
(2) The HEPA vacuum cleaner or other device used to prevent collapse
of bag during removal shall run continually during the operation until
it is completed at which time the bag shall be collapsed prior to
removal of the bag from the pipe.
(3) Where a separate waste bag is used along with a collection bag
and discarded after one use, the collection bag may be reused if rinsed
clean with amended water before reuse.
(iv) Negative pressure glove box systems. Negative pressure glove
boxes may be used to remove ACM or PACM from pipe runs with the
following specifications and work practices.
(A) Specifications--(1) Glove boxes shall be constructed with rigid
sides and made from metal or other material which can withstand the
weight of the ACM and PACM and water used during removal:
(2) A negative pressure generator shall be used to create negative
pressure in the system:
(3) An air filtration unit shall be attached to the box:
(4) The box shall be fitted with gloved apertures:
(5) An aperture at the base of the box shall serve as a bagging
outlet for waste ACM and water:
(6) A back-up generator shall be present on site:
(7) Waste bags shall consist of 6 mil thick plastic double-bagged
before they are filled or plastic thicker than 6 mil.
(B) Work practices--(1) At least two persons shall perform the
removal:
(2) The box shall be smoke-tested for leaks and any leaks sealed
prior to each use.
(3) Loose or damaged ACM adjacent to the box shall be wrapped and
sealed in two layers of 6 mil plastic prior to the job, or otherwise
made intact prior to the job.
(4) A HEPA filtration system shall be used to maintain pressure
barrier in box.
(v) Water spray process system. A water spray process system may be
used for removal of ACM and PACM from cold line piping if, employees
carrying out such process have completed a 40-hour separate training
course in its use, in addition to training required for employees
performing Class I work. The system shall meet the following
specifications and shall be performed
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by employees using the following work practices.
(A) Specifications--(1) Piping from which insulation will be removed
shall be surrounded on 3 sides by rigid framing,
(2) A 360 degree water spray, delivered through nozzles supplied by
a high pressure separate water line, shall be formed around the piping.
(3) The spray shall collide to form a fine aerosol which provides a
liquid barrier between workers and the ACM and PACM.
(B) Work practices--(1) The system shall be run for at least 10
minutes before removal begins.
(2) All removal shall take place within the barrier.
(3) The system shall be operated by at least three persons, one of
whom shall not perform removal but shall check equipment, and ensure
proper operation of the system.
(4) After removal, the ACM and PACM shall be bagged while still
inside the water barrier.
(vi) A small walk-in enclosure which accommodates no more than two
persons (mini-enclosure) may be used if the disturbance or removal can
be completely contained by the enclosure, with the following
specifications and work practices.
(A) Specifications--(1) The fabricated or job-made enclosure shall
be constructed of 6 mil plastic or equivalent:
(2) The enclosure shall be placed under negative pressure by means
of a HEPA filtered vacuum or similar ventilation unit:
(B) Work practices--(1) Before use, the mini-enclosure shall be
inspected for leaks and smoketested to detect breaches, and any breaches
sealed.
(2) Before reuse, the interior shall be completely washed with
amended water and HEPA-vacuumed.
(3) During use, air movement shall be directed away from the
employee's breathing zone within the mini-enclosure.
(6) Alternative control methods for Class I work. Class I work may
be performed using a control method which is not referenced in paragraph
(g)(5) of this section, or which modifies a control method referenced in
paragraph (g)(5) of this section, if the following provisions are
complied with:
(i) The control method shall enclose, contain or isolate the
processes or source of airborne asbestos dust, or otherwise capture or
redirect such dust before it enters the breathing zone of employees.
(ii) A certified industrial hygienist or licensed professional
engineer who is also qualified as a project designer as defined in
paragraph (b) of this section, shall evaluate the work area, the
projected work practices and the engineering controls and shall certify
in writing that: the planned control method is adequate to reduce direct
and indirect employee exposure to below the PELs under worst-case
conditions of use, and that the planned control method will prevent
asbestos contamination outside the regulated area, as measured by
clearance sampling which meets the requirements of EPA's Asbestos in
Schools Rule issued under AHERA, or perimeter monitoring which meets the
criteria in paragraph (g)(4)(ii)(B) of this section.
(A) Where the TSI or surfacing material to be removed is 25 linear
or 10 square feet or less , the evaluation required in paragraph (g)(6)
of this section may be performed by a ``qualified person'', and may omit
consideration of perimeter or clearance monitoring otherwise required.
(B) The evaluation of employee exposure required in paragraph (g)(6)
of this section, shall include and be based on sampling and analytical
data representing employee exposure during the use of such method under
worst-case conditions and by employees whose training and experience are
equivalent to employees who are to perform the current job.
(7) Work practices and engineering controls for Class II work. (i)
All Class II work shall be supervised by a qualified person as defined
in paragraph (b) of this section.
(ii) For all indoor Class II jobs, where the employer has not
produced a negative exposure assessment pursuant to paragraph
(f)(2)(iii) of this section, or where during the job, changed conditions
indicate there may be exposure above the PEL or where the employer
[[Page 128]]
does not remove the ACM in a substantially intact state, the employer
shall use one of the following methods to ensure that airborne asbestos
does not migrate from the regulated area;
(A) Critical barriers shall be placed over all openings to the
regulated area; or,
(B) The employer shall use another barrier or isolation method which
prevents the migration of airborne asbestos from the regulated area, as
verified by perimeter area monitoring or clearance monitoring which
meets the criteria set out in paragraph (g)(4)(ii)(B) of this section.
(C) Impermeable dropcloths shall be placed on surfaces beneath all
removal activity;
(iii) [Reserved]
(iv) All Class II asbestos work shall be performed using the work
practices and requirements set out above in paragraph (g)(1)(i) through
(g)(1)(iii) of this section.
(8) Additional controls for Class II work. Class II asbestos work
shall also be performed by complying with the work practices and
controls designated for each type of asbestos work to be performed, set
out in this paragraph. Where more than one control method may be used
for a type of asbestos work, the employer may choose one or a
combination of designated control methods. Class II work also may be
performed using a method allowed for Class I work, except that glove
bags and glove boxes are allowed if they fully enclose the Class II
material to be removed.
(i) For removing vinyl and asphalt flooring/deck materials which
contain ACM or for which in buildings constructed not later than 1980,
the employer has not verified the absence of ACM pursuant to paragraph
(g)(8)(i)(I): the employer shall ensure that employees comply with the
following work practices and that employees are trained in these
practices pursuant to paragraph (k)(9) of this section:
(A) Flooring/deck materials or its backing shall not be sanded.
(B) Vacuums equipped with HEPA filter, disposable dust bag, and
metal floor tool (no brush) shall be used to clean floors.
(C) Resilient sheeting shall be removed by cutting with wetting of
the snip point and wetting during delamination. Rip-up of resilient
sheet floor material is prohibited.
(D) All scraping of residual adhesive and/or backing shall be
performed using wet methods.
(E) Dry sweeping is prohibited.
(F) Mechanical chipping is prohibited unless performed in a negative
pressure enclosure which meets the requirements of paragraph (g)(5)(i)
of this section.
(G) Tiles shall be removed intact, unless the employer demonstrates
that intact removal is not possible.
(H) When tiles are heated and can be removed intact, wetting may be
omitted.
(I) Resilient flooring/deck material in buildings/vessels
constructed no later than 1980, including associated mastic and backing
shall be assumed to be asbestos-containing unless an industrial
hygienist determines that it is asbestos-free using recognized
analytical techniques.
(ii) For removing roofing material which contains ACM the employer
shall ensure that the following work practices are followed:
(A) Roofing material shall be removed in an intact state to the
extent feasible.
(B) Wet methods shall be used to remove roofing materials that are
not intact, or that will be rendered not intact during removal, unless
such wet methods are not feasible or will create safety hazards.
(C) Cutting machines shall be continuously misted during use, unless
a competent person determines that misting substantially decreases
worker safety.
(D) When removing built-up roofs with asbestos-containing roofing
felts and an aggregate surface using a power roof cutter, all dust
resulting from the cutting operation shall be collected by a HEPA dust
collector, or shall be HEPA vacuumed by vacuuming along the cut line.
When removing built-up roofs with asbestos-containing roofing felts and
a smooth surface using a power roof cutter, the dust resulting from the
cutting operation shall be collected either by a HEPA dust collector
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or HEPA vacuuming along the cut line, or by gently sweeping and then
carefully and completely wiping up the still-wet dust and debris left
along the cut line. The dust and debris shall be immediately bagged or
placed in covered containers.
(E) Asbestos-containing material that has been removed from a roof
shall not be dropped or thrown to the ground. Unless the material is
carried or passed to the ground by hand, it shall be lowered to the
ground via covered, dust-tight chute, crane or hoist:
(1) Any ACM that is not intact shall be lowered to the ground as
soon as is practicable, but in any event no later than the end of the
work shift. While the material remains on the roof it shall either be
kept wet, placed in an impermeable waste bag, or wrapped in plastic
sheeting.
(2) Intact ACM shall be lowered to the ground as soon as is
practicable, but in any event no later than the end of the work shift.
(F) Upon being lowered, unwrapped material shall be transferred to a
closed receptacle in such manner so as to preclude the dispersion of
dust.
(G) Roof level heating and ventilation air intake sources shall be
isolated or the ventilation system shall be shut down.
(H) Notwithstanding any other provision of this section, removal or
repair of sections of intact roofing less than 25 square feet in area
does not require use of wet methods or HEPA vacuuming as long as manual
methods which do not render the material non-intact are used to remove
the material and no visible dust is created by the removal method used.
In determining whether a job involves less than 25 square feet, the
employer shall include all removal and repair work performed on the same
roof on the same day.
(iii) When removing cementitious asbestos-containing siding and
shingles or transite panels containing ACM on building exteriors (other
than roofs, where paragraph (g)(8)(ii) of this section applies) the
employer shall ensure that the following work practices are followed:
(A) Cutting, abrading or breaking siding, shingles, or transite
panels shall be prohibited unless the employer can demonstrate that
methods less likely to result in asbestos fiber release cannot be used.
(B) Each panel or shingle shall be sprayed with amended water prior
to removal.
(C) Unwrapped or unbagged panels or shingles shall be immediately
lowered to the ground via a covered dust-tight chute, crane or hoist, or
be placed in an impervious waste bag or wrapped in plastic sheeting and
lowered to the ground no later than the end of the work shift.
(D) Nails shall be cut with flat, sharp instruments.
(iv) When removing gaskets containing ACM, the employer shall ensure
that the following work practices are followed:
(A) If a gasket is visibly deteriorated and unlikely to be removed
intact, removal shall be undertaken within a glovebag as described in
paragraph (g)(5)(ii) of this section.
(B) [Reserved]
(C) The gasket shall be immediately placed in a disposal container.
(D) Any scraping to remove residue must be performed wet.
(v) When performing any other Class II removal of asbestos
containing material for which specific controls have not been listed in
paragraph (g)(8)(iv) (A) through (D) of this section, the employer shall
ensure that the following work practices are complied with.
(A) The material shall be thoroughly wetted with amended water prior
to and during its removal.
(B) The material shall be removed in an intact state unless the
employer demonstrates that intact removal is not possible.
(C) Cutting, abrading or breaking the material shall be prohibited
unless the employer can demonstrate that methods less likely to result
in asbestos fiber release are not feasible.
(D) Asbestos-containing material removed, shall be immediately
bagged or wrapped, or kept wetted until transferred to a closed
receptacle, no later than the end of the work shift.
(vi) Alternative work practices and controls. Instead of the work
practices and controls listed in paragraphs (g)(8) (i) through (v) of
this section, the employer may use different or modified
[[Page 130]]
engineering and work practice controls if the following provisions are
complied with.
(A) The employer shall demonstrate by data representing employee
exposure during the use of such method under conditions which closely
resemble the conditions under which the method is to be used, that
employee exposure will not exceed the PELs under any anticipated
circumstances.
(B) A qualified person shall evaluate the work area, the projected
work practices and the engineering controls, and shall certify in
writing, that the different or modified controls are adequate to reduce
direct and indirect employee exposure to below the PELs under all
expected conditions of use and that the method meets the requirements of
this standard. The evaluation shall include and be based on data
representing employee exposure during the use of such method under
conditions which closely resemble the conditions under which the method
is to be used for the current job, and by employees whose training and
experience are equivalent to employees who are to perform the current
job.
(9) Work practices and engineering controls for Class III asbestos
work. Class III asbestos work shall be conducted using engineering and
work practice controls which minimize the exposure to employees
performing the asbestos work and to bystander employees.
(i) The work shall be performed using wet methods.
(ii) To the extent feasible, the work shall be performed using local
exhaust ventilation.
(iii) Where the disturbance involves drilling, cutting, abrading,
sanding, chipping, breaking, or sawing of thermal system insulation or
surfacing material, the employer shall use impermeable dropcloths and
shall isolate the operation using mini-enclosures or glove bag systems
pursuant to paragraph (g)(5) of this section or another isolation
method.
(iv) Where the employer does not demonstrate by a negative exposure
assessment performed in compliance with paragraph (f)(2)(iii) of this
section that the PELs will not be exceeded, or where monitoring results
show exceedances of a PEL, the employer shall contain the area using
impermeable dropcloths and plastic barriers or their equivalent, or
shall isolate the operation using mini-enclosure or glove bag systems
pursuant to paragraph (g)(5) of this section.
(v) Employees performing Class III jobs which involve the
disturbance of TSI or surfacing ACM or PACM or where the employer does
not demonstrate by a ``negative exposure assessment'' in compliance with
paragraph (f)(2)(iii) of this section that the PELs will not be exceeded
or where monitoring results show exceedances of the PEL, shall wear
respirators which are selected, used and fitted pursuant to provisions
of paragraph (h) of this section.
(10) Class IV asbestos work. Class IV asbestos jobs shall be
conducted by employees trained pursuant to the asbestos awareness
training program set out in paragraph (k)(9) of this section. In
addition, all Class IV jobs shall be conducted in conformity with the
requirements set out in paragraph (g)(1) of this section, mandating wet
methods, HEPA vacuums, and prompt clean up of debris containing ACM or
PACM.
(i) Employees cleaning up debris and waste in a regulated area where
respirators are required shall wear respirators which are selected, used
and fitted pursuant to provisions of paragraph (h) of this section.
(ii) Employers of employees cleaning up waste and debris in an area
where friable TSI or surfacing ACM/PACM is accessible, shall assume that
such waste and debris contain asbestos.
(11) Specific compliance methods for brake and clutch repair--(i)
Engineering controls and work practices for brake and clutch repair and
service. During automotive brake and clutch inspection, disassembly,
repair and assembly operations, the employer shall institute engineering
controls and work practices to reduce employee exposure to materials
containing asbestos using a negative pressure enclosure/HEPA vacuum
system method or low pressure/wet cleaning method, which meets the
detailed requirements set out in appendix L to this section. The
employer may also comply using an equivalent method which follows
written procedures which the employer demonstrates can
[[Page 131]]
achieve results equivalent to Method A. For facilities in which no more
than 5 pair of brakes or 5 clutches are inspected, disassembled,
repaired, or assembled per week, the method set for in paragraph [D] of
appendix L to this section may be used.
(ii) The employer may also comply by using an equivalent method
which follows written procedures, which the employer demonstrates can
achieve equivalent exposure reductions as do the two ``preferred
methods.'' Such demonstration must include monitoring data conducted
under workplace conditions closely resembling the process, type of
asbestos containing materials, control method, work practices and
environmental conditions which the equivalent method will be used, or
objective data, which document that under all reasonably foreseeable
conditions of brake and clutch repair applications, the method results
in exposures which are equivalent to the methods set out in appendix L
to this section.
(12) Alternative methods of compliance for installation, removal,
repair, and maintenance of certain roofing and pipeline coating
materials. Notwithstanding any other provision of this section, an
employer who complies with all provisions of this paragraph (g)(12) when
installing, removing, repairing, or maintaining intact pipeline
asphaltic wrap, or roof flashings which contain asbestos fibers
encapsulated or coated by bituminous or resinous compounds shall be
deemed to be in compliance with this section. If an employer does not
comply with all provisions of this paragraph (g)(12) or if during the
course of the job the material does not remain intact, the provisions of
paragraph (g)(8) of this section apply instead of this paragraph
(g)(12).
(i) Before work begins and as needed during the job, a qualified
person who is capable of identifying asbestos hazards in the workplace
and selecting the appropriate control strategy for asbestos exposure,
and who has the authority to take prompt corrective measures to
eliminate such hazards, shall conduct an inspection of the worksite and
determine that the roofing material is intact and will likely remain
intact.
(ii) All employees performing work covered by this paragraph (g)(12)
shall be trained in a training program that meets the requirements of
paragraph (k)(9)(viii) of this section.
(iii) The material shall not be sanded, abraded, or ground. Manual
methods which do not render the material non-intact shall be used.
(iv) Material that has been removed from a roof shall not be dropped
or thrown to the ground. Unless the material is carried or passed to the
ground by hand, it shall be lowered to the ground via covered, dust-
tight chute, crane or hoist. All such material shall be removed from the
roof as soon as is practicable, but in any event no later than the end
of the work shift.
(v) Where roofing products which have been labeled as containing
asbestos pursuant to paragraph (k)(8) of this section are installed on
non-residential roofs during operations covered by this paragraph
(g)(12), the employer shall notify the building owner of the presence
and location of such materials no later than the end of the job.
(vi) All removal or disturbance of pipeline asphaltic wrap shall be
performed using wet methods.
(h) Respiratory protection--(1) General. The employer shall provide
respirators, and ensure that they are used, where required by this
section. Respirators shall be used in the following circumstances:
(i) During all Class I asbestos jobs.
(ii) During all Class II work where the ACM is not removed in a
substantially intact state.
(iii) During all Class II and III work which is not performed using
wet methods, provided, however, that respirators need not be worn during
removal of ACM from sloped roofs when a negative exposure assessment has
been made and the ACM is removed in an intact state.
(iv) During all Class II and III asbestos jobs where the employer
does not produce a ``negative exposure assessment.''
(v) During all Class III jobs where TSI or surfacing ACM or PACM is
being disturbed.
(vi) During all Class IV work performed within regulated areas where
[[Page 132]]
employees performing other work are required to wear respirators.
(vii) During all work covered by this section where employees are
exposed above the TWA or excursion limit.
(viii) In emergencies.
(2) Respirator selection. (i) Where respirators are used, the
employer shall select and provide, at no cost to the employee, the
appropriate respirator as specified in table 1, or in paragraph
(h)(2)(iii) of this section, and shall ensure that the employee uses the
respirator provided.
(ii) The employer shall select respirators from among those jointly
approved as being acceptable for protection by the Mine Safety and
Health Administration (MSHA) and the National Institute for Occupational
Safety and Health (NIOSH) under the provisions of 30 CFR part 11.
(iii)(A) The employer shall provide a tight fitting powered, air-
purifying respirator in lieu of any negative-pressure respirator
specified in table 1 whenever:
(1) An employee chooses to use this type of respirator; and
(2) This respirator will provide adequate protection to the
employee.
(B) The employer shall inform any employee required to wear a
respirator under this paragraph that the employee may require the
employer to provide a powered, air-purifying respirator in lieu of a
negative pressure respirator.
Table 1--Respiratory Protection for Asbestos Fibers
------------------------------------------------------------------------
Airborne concentration of asbestos or
conditions of use Required respirator
------------------------------------------------------------------------
Not in excess of 1 f/cc (10 X PEL), or Half-mask air purifying
otherwise as required independent of respirator other than a
exposure pursuant to paragraph disposable respirator,
(h)(2)(iv) of this section. equipped with high efficiency
filters.
Not in excess of 5 f/xx (50 X PEL)..... Full facepiece air-purifying
respirator equipped with high
efficiency filters.
Not in excess of 10 f/cc (100 X PEL)... Any powered air-purifying
respirator equipped with high
efficiency filters or any
supplied air respirator
operated in continuous flow
mode.
Not in excess of 100 f/cc (1,000 X PEL) Full facepiece supplied air
respirator operated in
pressure demand mode.
Greater than 100 f/cc (1,000 X PEL) or Full facepiece supplied air
unknown concentration. respirator operated in
pressure demand mode, equipped
with an auxiliary positive
pressure self-contained
breathing apparatus.
------------------------------------------------------------------------
Note: a. Respirators assigned for high environmental concentrations may
be used at lower concentrations, or when required respirator use is
independent of concentration.
b. A high efficiency filter means a filter that is at least 99.97
percent efficient against mono-dispersed particles of 0.3 micrometers
in diameter or larger.
(iv) In addition to the above selection criterion, the employer
shall provide a half-mask air purifying respirator, other than a
disposable respirator, equipped with high efficiency filters whenever
the employee performs the following activities: Class II and III
asbestos jobs where the employer does not produce a negative exposure
assessment; and Class III jobs where TSI or surfacing ACM or PACM is
being disturbed.
(v) In addition to the selection criteria in paragraph (h)(2)(i)
through (iv), the employer shall provide a tight-fitting powered air
purifying respirator equipped with high efficiency filters or a full
facepiece supplied air respirator operated in the pressure demand mode
equipped with HEPA egress cartridges or an auxiliary positive pressure
self-contained breathing apparatus for all employees within the
regulated area where Class I work is being performed for which a
negative exposure assessment has not been produced and, the exposure
assessment indicates the exposure level will not exceed 1 f/cc as an 8-
hour time weighted average. A full facepiece supplied air respirator
operated in the pressure demand mode equipped with an auxiliary positive
pressure self-contained breathing apparatus shall be provided under such
conditions, if the exposure assessment indicates exposure levels above 1
f/cc as an 8-hour time weighted average.
(3) Respirator program. (i) Where respiratory protection is used,
the employer shall institute a respirator program in accordance with 29
CFR 1910.134(b), (d), (e), and (f).
[[Page 133]]
(ii) The employer shall permit each employee who uses a filter
respirator to change the filter elements whenever an increase in
breathing resistance is detected and shall maintain an adequate supply
of filter elements for this purpose.
(iii) Employees who wear respirators shall be permitted to leave
work areas to wash their faces and respirator facepieces whenever
necessary to prevent skin irritation associated with respirator use.
(iv) No employee shall be assigned to tasks requiring the use of
respirators if, based on his or her most recent examination, an
examining physician determines that the employee will be unable to
function normally wearing a respirator, or that the safety or health of
the employee or of other employees will be impaired by the use of a
respirator. Such employees shall be assigned to another job or given the
opportunity to transfer to a different position, the duties of which he
or she is able to perform with the same employer, in the same
geographical area, and with the same seniority, status, and rate of pay
and other job benefits he or she had just prior to such transfer, if
such a different position is available.
(4) Respirator fit testing. (i) The employer shall ensure that the
respirator issued to the employee exhibits the least possible facepiece
leakage and that the respirator is fitted properly.
(ii) Employers shall perform either quantitative or qualitative face
fit tests at the time of initial fitting and at least every 6 months
thereafter for each employee wearing a negative-pressure respirator. The
qualitative fit tests may be used only for testing the fit of half-mask
respirators where they are permitted to be worn, or of full-facepiece
air purifying respirators where they are worn at levels at which half-
facepiece air purifying respirators are permitted. Qualitative and
quantitative fit tests shall be conducted in accordance with appendix C
to this section. The tests shall be used to select facepieces that
provide the required protection as prescribed in table 1, in paragraph
(h)(2)(i) of this section.
(i) Protective clothing--(1) General. The employer shall provide and
require the use of protective clothing, such as coveralls or similar
whole-body clothing, head coverings, gloves, and foot coverings for any
employee exposed to airborne concentrations of asbestos that exceed the
TWA and/or excursion limit prescribed in paragraph (c) of this section,
or for which a required negative exposure assessment is not produced, or
for any employee performing Class I operations which involve the removal
of over 25 linear or 10 square feet of TSI or surfacing ACM or PACM.
(2) Laundering. (i) The employer shall ensure that laundering of
contaminated clothing is done so as to prevent the release of airborne
asbestos in excess of the TWA or excursion limit prescribed in paragraph
(c) of this section.
(ii) Any employer who gives contaminated clothing to another person
for laundering shall inform such person of the requirement in paragraph
(i)(2)(i) of this section to effectively prevent the release of airborne
asbestos in excess of the TWA excursion limit prescribed in paragraph
(c) of this section.
(3) Contaminated clothing. Contaminated clothing shall be
transported in sealed impermeable bags, or other closed, impermeable
containers, and be labeled in accordance with paragraph (k) of this
section.
(4) Inspection of protective clothing. (i) The qualified person
shall examine worksuits worn by employees at least once per workshift
for rips or tears that may occur during the performance of work.
(ii) When rips or tears are detected while an employee is working,
rips and tears shall be immediately mended, or the worksuit shall be
immediately replaced.
(j) Hygiene facilities and practices for employees. (1) Requirements
for employees performing Class I asbestos jobs involving over 25 linear
or 10 square feet of TSI or surfacing ACM and PACM.
(i) Decontamination areas. For all Class I jobs involving over 25
linear or 10 square feet of TSI or surfacing ACM or PACM, the employer
shall establish a decontamination area that is adjacent and connected to
the regulated area for the decontamination of such employees. The
decontamination area shall consist of an equipment room, shower area,
and clean room in series.
[[Page 134]]
The employer shall ensure that employees enter and exit the regulated
area through the decontamination area.
(A) Equipment room. The equipment room shall be supplied with
impermeable, labeled bags and containers for the containment and
disposal of contaminated protective equipment.
(B) Shower area. Shower facilities shall be provided which comply
with 29 CFR 1910.141(d)(3), unless the employer can demonstrate that
they are not feasible. The showers shall be adjacent both to the
equipment room and the clean room, unless the employer can demonstrate
that this location is not feasible. Where the employer can demonstrate
that it is not feasible to locate the shower between the equipment room
and the clean room, or where the work is performed outdoors, or when the
work involving asbestos exposure takes place on board a ship, the
employers shall ensure that employees:
(1) Remove asbestos contamination from their worksuits in the
equipment room using a HEPA vacuum before proceeding to a shower that is
not adjacent to the work area; or
(2) Remove their contaminated worksuits in the equipment room, then
don clean worksuits, and proceed to a shower that is not adjacent to the
work area.
(C) Clean change room. The clean room shall be equipped with a
locker or appropriate storage container for each employee's use. When
the employer can demonstrate that it is not feasible to provide a clean
change area adjacent to the work area, or where the work is performed
outdoors, or when the work takes place aboard a ship, the employer may
permit employees engaged in Class I asbestos jobs to clean their
protective clothing with a portable HEPA-equipped vacuum before such
employees leave the regulated area. Following showering, such employees
however must then change into street clothing in clean change areas
provided by the employer which otherwise meet the requirements of this
section.
(ii) Decontamination area entry procedures. The employer shall
ensure that employees:
(A) Enter the decontamination area through the clean room;
(B) Remove and deposit street clothing within a locker provided for
their use; and
(C) Put on protective clothing and respiratory protection before
leaving the clean room.
(D) Before entering the regulated area, the employer shall ensure
that employees pass through the equipment room.
(iii) Decontamination area exit procedures. The employer shall
ensure that:
(A) Before leaving the regulated area, employees shall remove all
gross contamination and debris from their protective clothing.
(B) Employees shall remove their protective clothing in the
equipment room and deposit the clothing in labeled impermeable bags or
containers.
(C) Employees shall not remove their respirators in the equipment
room.
(D) Employees shall shower prior to entering the clean room.
(E) After showering, employees shall enter the clean room before
changing into street clothes.
(iv) Lunch areas. Whenever food or beverages are consumed at the
worksite where employees are performing Class I asbestos work, the
employer shall provide lunch areas in which the airborne concentrations
of asbestos are below the permissible exposure limit and/or excursion
limit.
(2) Requirements for Class I work involving less than 25 linear or
10 square feet of TSI or surfacing and PACM, and for Class II and Class
III asbestos work operations where exposures exceed a PEL or where there
is no negative exposure assessment produced before the operation. (i)
The employer shall establish an equipment room or area that is adjacent
to the regulated area for the decontamination of employees and their
equipment which is contaminated with asbestos which shall consist of an
area covered by a impermeable drop cloth on the floor/deck or horizontal
working surface.
(ii) The area must be of sufficient size as to accommodate cleaning
of equipment and removing personal protective equipment without
spreading contamination beyond the area (as determined by visible
accumulations).
[[Page 135]]
(iii) Work clothing must be cleaned with a HEPA vacuum before it is
removed.
(iv) All equipment and surfaces of containers filled with ACM must
be cleaned prior to removing them from the equipment room or area.
(v) The employer shall ensure that employees enter and exit the
regulated area through the equipment room or area.
(3) Requirements for Class IV work. Employers shall ensure that
employees performing Class IV work within a regulated area comply with
the hygiene practice required of employees performing work which has a
higher classification within that regulated area. Otherwise employers of
employees cleaning up debris and material which is TSI or surfacing ACM
or identified as PACM shall provide decontamination facilities for such
employees which are required by paragraph (j)(2) of this section.
(4) Smoking in work areas. The employer shall ensure that employees
do not smoke in work areas where they are occupationally exposed to
asbestos because of activities in that work area.
(k) Communication of hazards. (1) This section applies to the
communication of information concerning asbestos hazards in shipyard
employment activities to facilitate compliance with this standard. Most
asbestos-related shipyard activities involve previously installed
building materials. Building/vessel owners often are the only and/or
best sources of information concerning them. Therefore, they, along with
employers of potentially exposed employees, are assigned specific
information conveying and retention duties under this section. Installed
Asbestos Containing Building/Vessel Material: Employers and building/
vessel owners shall identify TSI and sprayed or troweled on surfacing
materials as asbestos-containing unless the employer, by complying with
paragraph (k)(5) of this section determines that the material is not
asbestos-containing. Asphalt or vinyl flooring/decking material
installed in buildings or vessels no later than 1980 must also be
considered as asbestos containing unless the employer/owner, pursuant to
paragraph (g)(8)(i)(I) of this section, determines it is not asbestos
containing. If the employer or building/vessel owner has actual
knowledge or should have known, through the exercise of due diligence,
that materials other than TSI and sprayed-on or troweled-on surfacing
materials are asbestos-containing, they must be treated as such. When
communicating information to employees pursuant to this standard, owners
and employers shall identify ``PACM'' as ACM. Additional requirements
relating to communication of asbestos work on multi- employer worksites
are set out in paragraph (d) of this standard.
(2) Duties of building/vessel and facility owners. (i) Before work
subject to this standard is begun, building/vessel and facility owners
shall determine the presence, location, and quantity of ACM and/or PACM
at the work site pursuant to paragraph (k)(1) of this section.
(ii) Building/vessel and/or facility owners shall notify the
following persons of the presence, location and quantity of ACM or PACM,
at work sites in their buildings/facilities/vessels. Notification either
shall be in writing or shall consist of a personal communication between
the owner and the person to whom notification must be given or their
authorized representatives:
(A) Prospective employers applying or bidding for work whose
employees reasonably can be expected to work in or adjacent to areas
containing such material;
(B) Employees of the owner who will work in or adjacent to areas
containing such material:
(C) On multi-employer worksites, all employers of employees who will
be performing work within or adjacent to areas containing such
materials;
(D) Tenants who will occupy areas containing such materials.
(3) Duties of employers whose employees perform work subject to this
standard in or adjacent to areas containing ACM and PACM. Building/
vessel and facility owners whose employees perform such work shall
comply with these provisions to the extent applicable.
(i) Before work in areas containing ACM and PACM is begun, employers
shall identify the presence, location, and quantity of ACM, and/or PACM
[[Page 136]]
therein pursuant to paragraph (k)(1) of this section.
(ii) Before work under this standard is performed employers of
employees who will perform such work shall inform the following persons
of the location and quantity of ACM and/or PACM present at the worksite
and the precautions to be taken to ensure that airborne asbestos is
confined to the area.
(iii) Within 10 days of the completion of such work, the employer
whose employees have performed work subject to this standard, shall
inform the building/vessel or facility owner and employers of employees
who will be working in the area of the current location and quantity of
PACM and/or ACM remaining in the former regulated area and final
monitoring results, if any.
(4) In addition to the above requirements, all employers who
discover ACM and/or PACM on a work site shall convey information
concerning the presence, location and quantity of such newly discovered
ACM and/or PACM to the owner and to other employers of employees working
at the work site, within 24 hours of the discovery.
(5) Criteria to rebut the designation of installed material as PACM.
(i) At any time, an employer and/or building/vessel owner may
demonstrate, for purposes of this standard, that PACM does not contain
asbestos. Building/vessel owners and/or employers are not required to
communicate information about the presence of building material for
which such a demonstration pursuant to the requirements of paragraph
(k)(5)(ii) of this section has been made. However, in all such cases,
the information, data and analysis supporting the determination that
PACM does not contain asbestos, shall be retained pursuant to paragraph
(n) of this section.
(ii) An employer or owner may demonstrate that PACM does not contain
more than 1% asbestos by the following:
(A) Having completed an inspection conducted pursuant to the
requirements of AHERA (40 CFR part 763, subpart E) which demonstrates
that the material is not ACM; or
(B) Performing tests of the material containing PACM which
demonstrate that no ACM is present in the material. Such tests shall
include analysis of bulk samples collected in the manner described in 40
CFR 763.86. The tests, evaluation and sample collection shall be
conducted by an accredited inspector or by a CIH. Analysis of samples
shall be performed by persons or laboratories with proficiency
demonstrated by current successful participation in a nationally
recognized testing program such as the National Voluntary Laboratory
Accreditation Program (NVLAP) or the National Institute for Standards
and Technology (NIST) or the Round Robin for bulk samples administered
by the American Industrial Hygiene Association (AIHA), or an equivalent
nationally-recognized round robin testing program.
(iii) The employer and/or building/vessel owner may demonstrate that
flooring material including associated mastic and backing does not
contain asbestos, by a determination of an industrial hygienist based
upon recognized analytical techniques showing that the material is not
ACM.
(6) At the entrance to mechanical rooms/areas in which employees
reasonably can be expected to enter and which contain ACM and/or PACM,
the building/vessel owner shall post signs which identify the material
which is present, its location, and appropriate work practices which, if
followed, will ensure that ACM and/or PACM will not be disturbed. The
employer shall ensure, to the extent feasible, that employees who come
in contact with these signs can comprehend them. Means to ensure
employee comprehension may include the use of foreign languages,
pictographs, graphics, and awareness training.
(7) Signs. (i) Warning signs that demarcate the regulated area shall
be provided and displayed at each location where a regulated area is
required to be established by paragraph (e) of this section. Signs shall
be posted at such a distance from such a location that an employee may
read the signs and take necessary protective steps before entering the
area marked by the signs.
(ii)(A) The warning signs required by paragraph (k)(7) of this
section shall bear the following information:
[[Page 137]]
DANGER
ASBESTOS
CANCER AND LUNG DISEASE HAZARD
AUTHORIZED PERSONNEL ONLY
(B) In addition, where the use of respirators and protective
clothing is required in the regulated area under this section, the
warning signs shall include the following:
RESPIRATORS AND PROTECTIVE CLOTHING ARE REQUIRED IN THIS AREA
(iii) The employer shall ensure that employees working in and
contiguous to regulated areas comprehend the warning signs required to
be posted by paragraph (k)(7)(i) of this section. Means to ensure
employee comprehension may include the use of foreign languages,
pictographs and graphics.
(8) Labels. (i) Labels shall be affixed to all products containing
asbestos and to all containers containing such products, including waste
containers. Where feasible, installed asbestos products shall contain a
visible label.
(ii) Labels shall be printed in large, bold letters on a contrasting
background.
(iii) Labels shall be used in accordance with the requirements of 29
CFR 1910.1200(f) of OSHA's Hazard Communication standard, and shall
contain the following information:
DANGER
CONTAINS ASBESTOS FIBERS
AVOID CREATING DUST
CANCER AND LUNG DISEASE HAZARD
(iv) [Reserved]
(v) Labels shall contain a warning statement against breathing
asbestos fibers.
(vi) The provisions for labels required by paragraphs (k)(8) (i)
through (k)(8) (iii) of this section do not apply where:
(A) Asbestos fibers have been modified by a bonding agent, coating,
binder, or other material, provided that the manufacturer can
demonstrate that, during any reasonably foreseeable use, handling,
storage, disposal, processing, or transportation, no airborne
concentrations of asbestos fibers in excess of the permissible exposure
limit and/or excursion limit will be released, or
(B) Asbestos is present in a product in concentrations less than 1.0
percent.
(vii) When a building/vessel owner or employer identifies previously
installed PACM and/or ACM, labels or signs shall be affixed or posted so
that employees will be notified of what materials contain PACM and/or
ACM. The employer shall attach such labels in areas where they will
clearly be noticed by employees who are likely to be exposed, such as at
the entrance to mechanical room/areas. Signs required by paragraph
(k)(6) of this section may be posted in lieu of labels so long as they
contain information required for labelling. The employer shall ensure,
to the extent feasible, that employees who come in contact with these
signs or labels can comprehend them. Means to ensure employee
comprehension may include the use of foreign languages, pictographs,
graphics, and awareness training.
(9) Employee information and training. (i) The employer shall, at no
cost to the employee, institute a training program for all employees who
are likely to be exposed in excess of a PEL and for all employees who
perform Class I through IV asbestos operations, and shall ensure their
participation in the program.
(ii) Training shall be provided prior to or at the time of initial
assignment and at least annually thereafter.
(iii) Training for Class I operations and for Class II operations
that require the use of critical barriers (or equivalent isolation
methods) and/or negative pressure enclosures under this section shall be
the equivalent in curriculum, training method and length to the EPA
Model Accreditation Plan (MAP) asbestos abatement workers training (40
CFR part 763, subpart E, appendix C).
(iv) Training for other Class II work.
(A) For work with asbestos containing roofing materials, flooring
materials, siding materials, ceiling tiles, or transite panels, training
shall include at a minimum all the elements included in paragraph
(k)(9)(viii) of this section and in addition, the specific work
practices and engineering
[[Page 138]]
controls set forth in paragraph (g) of this section which specifically
relate to that category. Such course shall include ``hands-on'' training
and shall take at least 8 hours.
(B) An employee who works with more than one of the categories of
material specified in paragraph (k)(9)(iv)(A) of this section shall
receive training in the work practices applicable to each category of
material that the employee removes and each removal method that the
employee uses.
(C) For Class II operations not involving the categories of material
specified in paragraph (k)(9)(iv)(A) of this section, training shall be
provided which shall include at a minimum all the elements included in
paragraph (k)(9)(viii) of this section and in addition, the specific
work practices and engineering controls set forth in paragraph (g) of
this section which specifically relate to the category of material being
removed, and shall include ``hands-on'' training in the work practices
applicable to each category of material that the employee removes and
each removal method that the employee uses.
(v) Training for Class III employees shall be consistent with EPA
requirements for training of local education agency maintenance and
custodial staff as set forth at 40 CFR 763.92(a)(2). Such a course shall
also include ``hands-on'' training and shall take at least 16 hours.
Exception: For Class III operations for which the competent person
determines that the EPA curriculum does not adequately cover the
training needed to perform that activity, training shall include as a
minimum all the elements included in paragraph (k)(9)(viii) of this
section and in addition, the specific work practices and engineering
controls set forth in paragraph (g) of this section which specifically
relate to that activity, and shall include ``hands-on'' training in the
work practices applicable to each category of material that the employee
disturbs.
(vi) Training for employees performing Class IV operations shall be
consistent with EPA requirements for training of local education agency
maintenance and custodial staff as set forth at 40 CFR 763.92(a)(1).
Such a course shall include available information concerning the
locations of thermal system insulation and surfacing ACM/PACM, and
asbestos-containing flooring material, or flooring material where the
absence of asbestos has not yet been certified; and instruction in the
recognition of damage, deterioration, and delamination of asbestos
containing building materials. Such a course shall take at least 2
hours.
(vii) Training for employees who are likely to be exposed in excess
of the PEL and who are not otherwise required to be trained under
paragraph (k)(9) (iii) through (vi) of this section, shall meet the
requirements of paragraph (k)(9)(viii) of this section.
(viii) The training program shall be conducted in a manner that the
employee is able to understand. In addition to the content required by
the provisions in paragraphs (k)(9)(iii) through (vi) of this section,
the employer shall ensure that each such employee is informed of the
following:
(A) Methods of recognizing asbestos, including the requirement in
paragraph (k)(1) of this section to presume that certain building
materials contain asbestos;
(B) The health effects associated with asbestos exposure;
(C) The relationship between smoking and asbestos in producing lung
cancer;
(D) The nature of operations that could result in exposure to
asbestos, the importance of necessary protective controls to minimize
exposure including, as applicable, engineering controls, work practices,
respirators, housekeeping procedures, hygiene facilities, protective
clothing, decontamination procedures, emergency procedures, and waste
disposal procedures, and any necessary instruction in the use of these
controls and procedures; where Class III and IV work will be or is
performed, the contents of EPA 20T-2003, ``Managing Asbestos In-Place''
July 1990 or its equivalent in content;
(E) The purpose, proper use, fitting instructions, and limitations
of respirators as required by 29 CFR 1910.134;
(F) The appropriate work practices for performing the asbestos job;
[[Page 139]]
(G) Medical surveillance program requirements;
(H) The content of this standard including appendices;
(I) The names, addresses and phone numbers of public health
organizations which provide information, materials and/or conduct
programs concerning smoking cessation. The employer may distribute the
list of such organizations contained in appendix J to this section, to
comply with this requirement; and
(J) The requirements for posting signs and affixing labels and the
meaning of the required legends for such signs and labels.
(10) Access to training materials. (i) The employer shall make
readily available to affected employees without cost, written materials
relating to the employee training program, including a copy of this
regulation.
(ii) The employer shall provide to the Assistant Secretary and the
Director, upon request, all information and training materials relating
to the employee information and training program.
(iii) The employer shall inform all employees concerning the
availability of self-help smoking cessation program material. Upon
employee request, the employer shall distribute such material,
consisting of NIH Publication No, 89-1647, or equivalent self-help
material, which is approved or published by a public health organization
listed in appendix J to this section.
(l) Housekeeping--(1) Vacuuming. Where vacuuming methods are
selected, HEPA filtered vacuuming equipment must be used. The equipment
shall be used and emptied in a manner that minimizes the reentry of
asbestos into the workplace.
(2) Waste disposal. Asbestos waste, scrap, debris, bags, containers,
equipment, and contaminated clothing consigned for disposal shall be
collected and disposed of in sealed, labeled, impermeable bags or other
closed, labeled, impermeable containers except in roofing operations,
where the procedures specified in paragraph (g)(8)(ii) of this section
apply.
(3) Care of asbestos-containing flooring/deck material. (i) All
vinyl and asphalt flooring/deck material shall be maintained in
accordance with this paragraph unless the building/facility owner
demonstrates, pursuant to paragraph (g)(8)(i)(I) of this section that
the flooring/deck does not contain asbestos.
(ii) Sanding of flooring/deck material is prohibited.
(iii) Stripping of finishes shall be conducted using low abrasion
pads at speeds lower than 300 rpm and wet methods.
(iv) Burnishing or dry buffing may be performed only on flooring/
deck which has sufficient finish so that the pad cannot contact the
flooring/deck material.
(4) Waste and debris and accompanying dust in an area containing
accessible thermal system insulation or surfacing ACM/PACM or visibly
deteriorated ACM:
(i) Shall not be dusted or swept dry, or vacuumed without using a
HEPA filter;
(ii) Shall be promptly cleaned up and disposed of in leak tight
containers.
(m) Medical surveillance--(1) General--(i) Employees covered. (A)
The employer shall institute a medical surveillance program for all
employees who for a combined total of 30 or more days per year are
engaged in Class I, II and III work or are exposed at or above a
permissible exposure limit. For purposes of this paragraph, any day in
which a worker engages in Class II or Class III operations or a
combination thereof on intact material for one hour or less (taking into
account the entire time spent on the removal operation, including
cleanup) and, while doing so, adheres fully to the work practices
specified in this standard, shall not be counted.
(B) For employees otherwise required by this standard to wear a
negative pressure respirator, employers shall ensure employees are
physically able to perform the work and use the equipment. This
determination shall be made under the supervision of a physician.
(ii) Examination. (A) The employer shall ensure that all medical
examinations and procedures are performed by or under the supervision of
a licensed physician, and are provided at no cost
[[Page 140]]
to the employee and at a reasonable time and place.
(B) Persons other than such licensed physicians who administer the
pulmonary function testing required by this section shall complete a
training course in spirometry sponsored by an appropriate academic or
professional institution.
(2) Medical examinations and consultations--(i) Frequency. The
employer shall make available medical examinations and consultations to
each employee covered under paragraph (m)(1)(i) of this section on the
following schedules:
(A) Prior to assignment of the employee to an area where negative-
pressure respirators are worn;
(B) When the employee is assigned to an area where exposure to
asbestos may be at or above the permissible exposure limit for 30 or
more days per year, or engage in Class I, II, or III work for a combined
total of 30 or more days per year, a medical examination must be given
within 10 working days following the thirtieth day of exposure;
(C) And at least annually thereafter.
(D) If the examining physician determines that any of the
examinations should be provided more frequently than specified, the
employer shall provide such examinations to affected employees at the
frequencies specified by the physician.
(E) Exception: No medical examination is required of any employee if
adequate records show that the employee has been examined in accordance
with this paragraph within the past 1-year period.
(ii) Content. Medical examinations made available pursuant to
paragraphs (m)(2)(i) (A) through (m)(2)(i) (C) of this section shall
include:
(A) A medical and work history with special emphasis directed to the
pulmonary, cardiovascular, and gastrointestinal systems.
(B) On initial examination, the standardized questionnaire contained
in part 1 of appendix D to this section and, on annual examination, the
abbreviated standardized questionnaire contained in part 2 of appendix D
to this section.
(C) A physical examination directed to the pulmonary and
gastrointestinal systems, including a chest x-ray to be administered at
the discretion of the physician, and pulmonary function tests of forced
vital capacity (FVC) and forced expiratory volume at one second
(FEV(1)). Interpretation and classification of chest roentgenogram shall
be conducted in accordance with appendix E to this section.
(D) Any other examinations or tests deemed necessary by the
examining physician.
(3) Information provided to the physician. The employer shall
provide the following information to the examining physician:
(i) A copy of this standard and appendices D, E, and I to this
section;
(ii) A description of the affected employee's duties as they relate
to the employee's exposure;
(iii) The employee's representative exposure level or anticipated
exposure level;
(iv) A description of any personal protective and respiratory
equipment used or to be used; and
(v) Information from previous medical examinations of the affected
employee that is not otherwise available to the examining physician.
(4) Physician's written opinion. (i) The employer shall obtain a
written opinion from the examining physician. This written opinion shall
contain the results of the medical examination and shall include:
(A) The physician's opinion as to whether the employee has any
detected medical conditions that would place the employee at an
increased risk of material health impairment from exposure to asbestos;
(B) Any recommended limitations on the employee or on the use of
personal protective equipment such as respirators; and
(C) A statement that the employee has been informed by the physician
of the results of the medical examination and of any medical conditions
that may result from asbestos exposure.
(D) A statement that the employee has been informed by the physician
of the increased risk of lung cancer attributable to the combined effect
of smoking and asbestos exposure.
(ii) The employer shall instruct the physician not to reveal in the
written opinion given to the employer specific
[[Page 141]]
findings or diagnoses unrelated to occupational exposure to asbestos.
(iii) The employer shall provide a copy of the physician's written
opinion to the affected employee within 30 days from its receipt.
(n) Recordkeeping--(1) Objective data relied on pursuant to
paragraph (f) of this section. (i) Where the employer has relied on
objective data that demonstrates that products made from or containing
asbestos or the activity involving such products or material are not
capable of releasing fibers of asbestos in concentrations at or above
the permissible exposure limit and/or excursion limit under the expected
conditions of processing, use, or handling to satisfy the requirements
of paragraph (f) of this section, the employer shall establish and
maintain an accurate record of objective data reasonably relied upon in
support of the exemption.
(ii) The record shall include at least the following information:
(A) The product qualifying for exemption;
(B) The source of the objective data;
(C) The testing protocol, results of testing, and/or analysis of the
material for the release of asbestos;
(D) A description of the operation exempted and how the data support
the exemption; and
(E) Other data relevant to the operations, materials, processing, or
employee exposures covered by the exemption.
(iii) The employer shall maintain this record for the duration of
the employer's reliance upon such objective data.
(2) Exposure measurements. (i) The employer shall keep an accurate
record of all measurements taken to monitor employee exposure to
asbestos as prescribed in paragraph (f) of this section. Note: The
employer may utilize the services of qualified organizations such as
industry trade associations and employee associations to maintain the
records required by this section.
(ii) This record shall include at least the following information:
(A) The date of measurement;
(B) The operation involving exposure to asbestos that is being
monitored;
(C) Sampling and analytical methods used and evidence of their
accuracy;
(D) Number, duration, and results of samples taken;
(E) Type of protective devices worn, if any; and
(F) Name, social security number, and exposure of the employees
whose exposures are represented.
(iii) The employer shall maintain this record for at least thirty
(30) years, in accordance with 29 CFR 1910.20.
(3) Medical surveillance. (i) The employer shall establish and
maintain an accurate record for each employee subject to medical
surveillance by paragraph (m) of this section, in accordance with 29 CFR
1910.20.
(ii) The record shall include at least the following information:
(A) The name and social security number of the employee;
(B) A copy of the employee's medical examination results, including
the medical history, questionnaire responses, results of any tests, and
physician's recommendations.
(C) Physician's written opinions;
(D) Any employee medical complaints related to exposure to asbestos;
and
(E) A copy of the information provided to the physician as required
by paragraph (m) of this section.
(iii) The employer shall ensure that this record is maintained for
the duration of employment plus thirty (30) years, in accordance with 29
CFR 1910.20.
(4) Training records. The employer shall maintain all employee
training records for one (1) year beyond the last date of employment by
that employer.
(5) Data to rebut PACM. (i) Where the building owner and employer
have relied on data to demonstrate that PACM is not asbestos-containing,
such data shall be maintained for as long as they are relied upon to
rebut the presumption.
(ii) [Reserved]
(6) Records of required notification. (i) Where the building/vessel
owner has communicated and received information concerning the identity,
location and quantity of ACM and PACM, written records of such
notifications and their content shall be maintained by
[[Page 142]]
the owner for the duration of ownership and shall be transferred to
successive owners of such buildings/facilities/vessels.
(ii) [Reserved]
(7) Availability. (i) The employer, upon written request, shall make
all records required to be maintained by this section available to the
Assistant Secretary and the Director for examination and copying.
(ii) The employer, upon request, shall make any exposure records
required by paragraphs (f) and (n) of this section available for
examination and copying to affected employees, former employees,
designated representatives, and the Assistant Secretary, in accordance
with 29 CFR 1910.20(a) through (e) and (g) through (i).
(iii) The employer, upon request, shall make employee medical
records required by paragraphs (m) and (n) of this section available for
examination and copying to the subject employee, anyone having the
specific written consent of the subject employee, and the Assistant
Secretary, in accordance with 29 CFR 1910.20.
(8) Transfer of records. (i) The employer shall comply with the
requirements concerning transfer of records set forth in 29 CFR 1910.20
(h).
(ii) Whenever the employer ceases to do business and there is no
successor employer to receive and retain the records for the prescribed
period, the employer shall notify the Director at least 90 days prior to
disposal and, upon request, transmit them to the Director.
(o) Qualified person--(1) General. On all shipyard worksites covered
by this standard, the employer shall designate a qualified person,
having the qualifications and authority for ensuring worker safety and
health required by subpart C, General Safety and Health Provisions for
Construction (29 CFR 1926.20 through 1926.32).
(2) Required inspections by the qualified person. Sec.
1926.20(b)(2) which requires health and safety prevention programs to
provide for frequent and regular inspections of the job sites,
materials, and equipment to be made by qualified persons, is
incorporated.
(3) Additional inspections. In addition, the qualified person shall
make frequent and regular inspections of the job sites, in order to
perform the duties set out in paragraph (o)(3)(i) of this section. For
Class I jobs, on-site inspections shall be made at least once during
each work shift, and at any time at employee request. For Class II, III
and IV jobs, on-site inspections shall be made at intervals sufficient
to assess whether conditions have changed, and at any reasonable time at
employee request.
(i) On all worksites where employees are engaged in Class I or II
asbestos work, the qualified person designated in accordance with
paragraph (e)(6) of this section shall perform or supervise the
following duties, as applicable:
(A) Set up the regulated area, enclosure, or other containment;
(B) Ensure (by on-site inspection) the integrity of the enclosure or
containment;
(C) Set up procedures to control entry to and exit from the
enclosure and/or area;
(D) Supervise all employee exposure monitoring required by this
section and ensure that it is conducted as required by paragraph (f) of
this section;
(E) Ensure that employees working within the enclosure and/or using
glove bags wear respirators and protective clothing as required by
paragraphs (h) and (i) of this section;
(F) Ensure through on-site supervision, that employees set up, use,
and remove engineering controls, use work practices and personal
protective equipment in compliance with all requirements;
(G) Ensure that employees use the hygiene facilities and observe the
decontamination procedures specified in paragraph (j) of this section;
(H) Ensure that through on-site inspection, engineering controls are
functioning properly and employees are using proper work practices; and
(I) Ensure that notification requirements in paragraph (k) of this
section are met.
(4) Training for the competent person. (i) For Class I and II
asbestos work the qualified person shall be trained in all
[[Page 143]]
aspects of asbestos removal and handling, including: Abatement,
installation, removal and handling; the contents of this standard; the
identification of asbestos; removal procedures, where appropriate; and
other practices for reducing the hazard. Such training shall be obtained
in a comprehensive course for supervisors, that meets the criteria of
EPA's Model Accreditation Plan (40 CFR part 763, subpart E, appendix C),
such as a course conducted by an EPA-approved or state-approved training
provider, certified by EPA or a state, or a course equivalent in
stringency, content, and length.
(ii) For Class III and IV asbestos work, the qualified person shall
be trained in aspects of asbestos handling appropriate for the nature of
the work, to include procedures for setting up glove bags and mini-
enclosures, practices for reducing asbestos exposures, use of wet
methods, the contents of this standard, and the identification of
asbestos. Such training shall include successful completion of a course
that is consistent with EPA requirements for training of local education
agency maintenance and custodial staff as set forth at 40 CFR
763.92(a)(2), or its equivalent in stringency, content, and length.
Qualified persons for Class III and Class IV work may also be trained
pursuant to the requirements of paragraph (o)(4)(i) of this section.
(p) Appendices. (1) Appendices A, C, D, and E to this section are
incorporated as part of this section and the contents of these
appendices are mandatory.
(2) Appendices B, F, H, I, J, and K to this section are
informational and are not intended to create any additional obligations
not otherwise imposed or to detract from any existing obligations.
(q) Dates. (1) This standard shall become effective October 11,
1994.
(2) The provisions of 29 CFR 1926.58 and 29 CFR 1910.1001 remain in
effect until the start-up dates of the equivalent provisions of this
standard.
(3) Start-up dates. All obligations of this standard commence on the
effective date except as follows:
(i) Methods of compliance. The engineering and work practice
controls required by paragraph (g) of this section shall be implemented
by October 1, 1995.
(ii) Respiratory protection. Respiratory protection required by
paragraph (h) of this section shall be provided by October 1, 1995.
(iii) Hygiene facilities and practices for employees. Hygiene
facilities and practices required by paragraph (j) of this section shall
be provided by October 1, 1995.
(iv) Communication of hazards. Identification, notification,
labeling and sign posting, and training required by paragraph (k) of
this section shall be provided by October 1, 1995.
(v) Housekeeping. Housekeeping practices and controls required by
paragraph (1) of this section shall be provided by October 1, 1995.
(vi) Medical surveillance required by paragraph (m) of this section
shall be provided by October 1, 1995.
(vii) The designation and training of qualified persons required by
paragraph (o) of this section shall be completed by October 1, 1995.
Appendix A to Sec. 1915.1001--OSHA Reference Method (Mandatory)
This mandatory appendix specifies the procedure for analyzing air
samples for asbestos, and specifies quality control procedures that must
be implemented by laboratories performing the analysis. The sampling and
analytical methods described below represent the elements of the
available monitoring methods (such as appendix B to this section, the
most current version of the OSHA method ID-160, or the most current
version of the NIOSH Method 7400) which OSHA considers to be essential
to achieve adequate employee exposure monitoring while allowing
employers to use methods that are already established within their
organizations. All employers who are required to conduct air monitoring
under paragraph (f) of this section are required to utilize analytical
laboratories that use this procedure, or an equivalent method, for
collecting and analyzing samples.
Sampling and Analytical Procedure
1. The sampling medium for air samples shall be mixed cellulose
ester filter membranes. These shall be designated by the manufacturer as
suitable for asbestos counting. See below for rejection of blanks.
2. The preferred collection device shall be the 25-mm diameter
cassette with an open-faced 50-mm extension cowl. The 37-mm cassette may
be used if necessary but only if written justification for the need to
use the
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37-mm filter cassette accompanies the sample results in the employee's
exposure monitoring record. Other cassettes such as the Bell-mouth may
be used within the limits of their validation. Do not reuse or reload
cassettes for asbestos sample collection.
3. An air flow rate between 0.5 liter/min and 5 liters/min shall be
selected for the 25-mm cassette. If the 37-mm cassette is used, an air
flow rate between 1 liter/min and 5 liters/min shall be selected.
4. Where possible, a sufficient air volume for each air sample shall
be collected to yield between 100 and 1,300 fibers per square millimeter
on the membrane filter. If a filter darkens in appearance or if loose
dust is seen on the filter, a second sample shall be started.
5. Ship the samples in a rigid container with sufficient packing
material to prevent dislodging the collected fibers. Packing material
that has a high electrostatic charge on its surface (e.g., expanded
polystyrene) cannot be used because such material can cause loss of
fibers to the sides of the cassette.
6. Calibrate each personal sampling pump before and after use with a
representative filter cassette installed between the pump and the
calibration devices.
7. Personal samples shall be taken in the ``breathing zone'' of the
employee (i.e., attached to or near the collar or lapel near the
worker's face).
8. Fiber counts shall be made by positive phase contrast using a
microscope with an 8 to 10 X eyepiece and a 40 to 45 X objective for a
total magnification of approximately 400 X and a numerical aperture of
0.65 to 0.75. The microscope shall also be fitted with a green or blue
filter.
9. The microscope shall be fitted with a Walton-Beckett eyepiece
graticule calibrated for a field diameter of 100 micrometers (2 micrometers).
10. The phase-shift detection limit of the microscope shall be about
3 degrees measured using the HSE phase shift test slide as outlined
below.
a. Place the test slide on the microscope stage and center it under
the phase objective.
b. Bring the blocks of grooved lines into focus.
Note: The slide consists of seven sets of grooved lines (ca. 20
grooves to each block) in descending order of visibility from sets 1 to
7, seven being the least visible. The requirements for asbestos,
tremolite, anthophyllite, and actinolite counting are that the
microscope optics must resolve the grooved lines in set 3 completely,
although they may appear somewhat faint, and that the grooved lines in
sets 6 and 7 must be invisible. Sets 4 and 5 must be at least partially
visible but may vary slightly in visibility between microscopes. A
microscope that fails to meet these requirements has either too low or
too high a resolution to be used for asbestos, tremolite, anthophyllite,
and actinolite counting.
c. If the image deteriorates, clean and adjust the microscope
optics. If the problem persists, consult the microscope manufacturer.
11. Each set of samples taken will include 10% field blanks or a
minimum of 2 field blanks. These blanks must come from the same lot as
the filters used for sample collection. The field blank results shall be
averaged and subtracted from the analytical results before reporting. A
set consists of any sample or group of samples for which an evaluation
for this standard must be made. Any samples represented by a field blank
having a fiber count in excess of the detection limit of the method
being used shall be rejected.
12. The samples shall be mounted by the acetone/triacetin method or
a method with an equivalent index of refraction and similar clarity.
13. Observe the following counting rules.
a. Count only fibers equal to or longer than 5 micrometers. Measure
the length of curved fibers along the curve.
b. In the absence of other information, count all particles as
asbestos that have a length-to-width ratio (aspect ratio) of 3 to 1 or
greater.
c. Fibers lying entirely within the boundary of the Walton-Beckett
graticule field shall receive a count of 1. Fibers crossing the boundary
once, having one end within the circle, shall receive the count of one
half (\1/2\). Do not count any fiber that crosses the graticule boundary
more than once. Reject and do not count any other fibers even though
they may be visible outside the graticule area.
d. Count bundles of fibers as one fiber unless individual fibers can
be identified by observing both ends of an individual fiber.
e. Count enough graticule fields to yield 100 fibers. Count a
minimum of 20 fields; stop counting at 100 fields regardless of fiber
count.
14. Blind recounts shall be conducted at the rate of 10 percent.
Quality Control Procedures
1. Intra-laboratory program. Each laboratory and/or each company
with more than one microscopist counting slides shall establish a
statistically designed quality assurance program involving blind
recounts and comparisons between microscopists to monitor the
variability of counting by each microscopist and between microscopists.
In a company with more than one laboratory, the program shall include
all laboratories and shall also evaluate the laboratory-to-laboratory
variability.
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2. a. Interlaboratory program. Each laboratory analyzing asbestos,
tremolite, anthophyllite, and actinolite samples for compliance
determination shall implement an interlaboratory quality assurance
program that as a minimum includes participation of at least two other
independent laboratories. Each laboratory shall participate in round
robin testing at least once every 6 months with at least all the other
laboratories in its interlaboratory quality assurance group. Each
laboratory shall submit slides typical of its own work load for use in
this program. The round robin shall be designed and results analyzed
using appropriate statistical methodology.
b. All laboratories should participate in a national sample testing
scheme such as the Proficiency Analytical Testing Program (PAT), the
Asbestos Registry sponsored by the American Industrial Hygiene
Association (AIHA).
3. All individuals performing asbestos, tremolite, anthophyllite,
and actinolite analysis must have taken the NIOSH course for sampling
and evaluating airborne asbestos, tremolite, anthophyllite, and
actinolite dust or an equivalent course.
4. When the use of different microscopes contributes to differences
between counters and laboratories, the effect of the different
microscope shall be evaluated and the microscope shall be replaced, as
necessary.
5. Current results of these quality assurance programs shall be
posted in each laboratory to keep the microscopists informed.
Appendix B to Sec. 1915.1001--Detailed Procedures for Asbestos Sampling
and Analysis (Non-mandatory)
Matrix: Air
OSHA Permissible Exposure Limits:
Time Weighted Average............... 0.1 fiber/cc
Excursion Level (30 minutes)........ 1.0 fiber/cc
Collection Procedure:
A known volume of air is drawn through a 25-mm diameter cassette
containing a mixed-cellulose ester filter. The cassette must be equipped
with an electrically conductive 50-mm extension cowl. The sampling time
and rate are chosen to give a fiber density of between 100 to 1,300
fibers/mm\2\ on the filter.
Recommended Sampling Rate............... 0.5 to 5.0 liters/minute (L/
min)
Recommended Air Volumes:
Minimum............................. 25 L
Maximum............................. 2,400 L
------------------------------------------------------------------------
Analytical Procedure: A portion of the sample filter is cleared and
prepared for asbestos fiber counting by Phase Contrast Microscopy (PCM)
at 400X.
Commercial manufacturers and products mentioned in this method are
for descriptive use only and do not constitute endorsements by USDOL-
OSHA. Similar products from other sources can be substituted.
1. Introduction
This method describes the collection of airborne asbestos fibers
using calibrated sampling pumps with mixed-cellulose ester (MCE) filters
and analysis by phase contrast microscopy (PCM). Some terms used are
unique to this method and are defined below: Asbestos: A term for
naturally occurring fibrous minerals. Asbestos includes chrysotile,
crocidolite, amosite (cummingtonite-grunerite asbestos), tremolite
asbestos, actinolite asbestos, anthophyllite asbestos, and any of these
minerals that have been chemically treated and/or altered. The precise
chemical formulation of each species will vary with the location from
which it was mined. Nominal compositions are listed:
Chrysotile................................ Mg3Si2O5(OH)4
Crocidolite............................... Na2Fe32+Fe23+Si8O22(OH)2
Amosite................................... (Mg,Fe)7Si8O22(OH)2
Tremolite-actinolite...................... Ca2(Mg,Fe)5Si8O22(OH)2
Anthophyllite............................. (Mg,Fe)7Si8O22(OH)2
Asbestos Fiber: A fiber of asbestos which meets the criteria
specified below for a fiber.
Aspect Ratio: The ratio of the length of a fiber to it's diameter
(e.g. 3:1, 5:1 aspect ratios).
Cleavage Fragments: Mineral particles formed by comminution of
minerals, especially those characterized by parallel sides and a
moderate aspect ratio (usually less than 20:1).
Detection Limit: The number of fibers necessary to be 95% certain
that the result is greater than zero.
Differential Counting: The term applied to the practice of excluding
certain kinds of fibers from the fiber count because they do not appear
to be asbestos.
Fiber: A particle that is 5 [micro]m or longer, with a length-to-
width ratio of 3 to 1 or longer.
Field: The area within the graticule circle that is superimposed on
the microscope image.
Set: The samples which are taken, submitted to the laboratory,
analyzed, and for which, interim or final result reports are generated.
Tremolite, Anthophyllite, and Actinolite: The non-asbestos form of
these minerals which meet the definition of a fiber. It includes any
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of these minerals that have been chemically treated and/or altered.
Walton-Beckett Graticule: An eyepiece graticule specifically
designed for asbestos fiber counting. It consists of a circle with a
projected diameter of 100 2 [micro]m (area of
about 0.00785 mm\2\) with a crosshair having tic-marks at 3-[micro]m
intervals in one direction and 5-[micro]m in the orthogonal direction.
There are marks around the periphery of the circle to demonstrate the
proper sizes and shapes of fibers. This design is reproduced in figure
1. The disk is placed in one of the microscope eyepieces so that the
design is superimposed on the field of view.
1.1. History
Early surveys to determine asbestos exposures were conducted using
impinger counts of total dust with the counts expressed as million
particles per cubic foot. The British Asbestos Research Council
recommended filter membrane counting in 1969. In July 1969, the Bureau
of Occupational Safety and Health published a filter membrane method for
counting asbestos fibers in the United States. This method was refined
by NIOSH and published as P & CAM 239. On May 29, 1971, OSHA specified
filter membrane sampling with phase contrast counting for evaluation of
asbestos exposures at work sites in the United States. The use of this
technique was again required by OSHA in 1986. Phase contrast microscopy
has continued to be the method of choice for the measurement of
occupational exposure to asbestos.
1.2. Principle
Air is drawn through a MCE filter to capture airborne asbestos
fibers. A wedge shaped portion of the filter is removed, placed on a
glass microscope slide and made transparent. A measured area (field) is
viewed by PCM. All the fibers meeting defined criteria for asbestos are
counted and considered a measure of the airborne asbestos concentration.
1.3. Advantages and Disadvantages
There are four main advantages of PCM over other methods:
(1) The technique is specific for fibers. Phase contrast is a fiber
counting technique which excludes non-fibrous particles from the
analysis.
(2) The technique is inexpensive and does not require specialized
knowledge to carry out the analysis for total fiber counts.
(3) The analysis is quick and can be performed on-site for rapid
determination of air concentrations of asbestos fibers.
(4) The technique has continuity with historical epidemiological
studies so that estimates of expected disease can be inferred from long-
term determinations of asbestos exposures.
The main disadvantage of PCM is that it does not positively identify
asbestos fibers. Other fibers which are not asbestos may be included in
the count unless differential counting is performed. This requires a
great deal of experience to adequately differentiate asbestos from non-
asbestos fibers. Positive identification of asbestos must be performed
by polarized light or electron microscopy techniques. A further
disadvantage of PCM is that the smallest visible fibers are about 0.2
[micro]m in diameter while the finest asbestos fibers may be as small as
0.02 [micro]m in diameter. For some exposures, substantially more fibers
may be present than are actually counted.
1.4. Workplace Exposure
Asbestos is used by the construction industry in such products as
shingles, floor tiles, asbestos cement, roofing felts, insulation and
acoustical products. Non-construction uses include brakes, clutch
facings, paper, paints, plastics, and fabrics. One of the most
significant exposures in the workplace is the removal and encapsulation
of asbestos in schools, public buildings, and homes. Many workers have
the potential to be exposed to asbestos during these operations.
About 95% of the asbestos in commercial use in the United States is
chrysotile. Crocidolite and amosite make up most of the remainder.
Anthophyllite and tremolite or actinolite are likely to be encountered
as contaminants in various industrial products.
1.5. Physical Properties
Asbestos fiber possesses a high tensile strength along its axis, is
chemically inert, non-combustible, and heat resistant. It has a high
electrical resistance and good sound absorbing properties. It can be
weaved into cables, fabrics or other textiles, and also matted into
asbestos papers, felts, or mats.
2. Range and Detection Limit
2.1. The ideal counting range on the filter is 100 to 1,300 fibers/
mm\2\. With a Walton-Beckett graticule this range is equivalent to 0.8
to 10 fibers/field. Using NIOSH counting statistics, a count of 0.8
fibers/field would give an approximate coefficient of variation (CV) of
0.13.
2.2. The detection limit for this method is 4.0 fibers per 100
fields or 5.5 fibers/mm\2\. This was determined using an equation to
estimate the maximum CV possible at a specific concentration (95%
confidence) and a Lower Control Limit of zero. The CV value was then
used to determine a corresponding concentration from historical CV vs
fiber relationships. As an example:
Lower Control Limit (95% Confidence) = AC--1.645(CV)(AC)
Where:
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AC = Estimate of the airborne fiber concentration (fibers/cc) Setting
the Lower Control Limit = 0 and solving for CV:
0 = AC--1.645(CV)(AC)
CV = 0.61
This value was compared with CV vs. count curves. The count at which
CV = 0.61 for Leidel-Busch counting statistics (8.9.) or for an OSHA
Salt Lake Technical Center (OSHA-SLTC) CV curve (see appendix A for
further information) was 4.4 fibers or 3.9 fibers per 100 fields,
respectively. Although a lower detection limit of 4 fibers per 100
fields is supported by the OSHA-SLTC data, both data sets support the
4.5 fibers per 100 fields value.
3. Method Performance--Precision and Accuracy
Precision is dependent upon the total number of fibers counted and
the uniformity of the fiber distribution on the filter. A general rule
is to count at least 20 and not more than 100 fields. The count is
discontinued when 100 fibers are counted, provided that 20 fields have
already been counted. Counting more than 100 fibers results in only a
small gain in precision. As the total count drops below 10 fibers, an
accelerated loss of precision is noted.
At this time, there is no known method to determine the absolute
accuracy of the asbestos analysis. Results of samples prepared through
the Proficiency Analytical Testing (PAT) Program and analyzed by the
OSHA-SLTC showed no significant bias when compared to PAT reference
values. The PAT samples were analyzed from 1987 to 1989 (N=36) and the
concentration range was from 120 to 1,300 fibers/mm\2\.
4. Interferences
Fibrous substances, if present, may interfere with asbestos
analysis.
Some common fibers are:
fiberglass
anhydrate
plant fibers
perlite veins
gypsum
some synthetic fibers
membrane structures
sponge spicules
diatoms
microorganism
wollastonite
The use of electron microscopy or optical tests such as polarized
light, and dispersion staining may be used to differentiate these
materials from asbestos when necessary.
5. Sampling
5.1. Equipment
5.1.1. Sample assembly (The assembly is shown in figure 3).
Conductive filter holder consisting of a 25-mm diameter, 3-piece
cassette having a 50-mm long electrically conductive extension cowl.
Backup pad, 25-mm, cellulose. Membrane filter, mixed-cellulose ester
(MCE), 25-mm, plain, white, 0.4 to 1.2-[micro]m pore size.
Notes: (a) DO NOT RE-USE CASSETTES.
(b) Fully conductive cassettes are required to reduce fiber loss to
the sides of the cassette due to electrostatic attraction.
(c) Purchase filters which have been selected by the manufacturer
for asbestos counting or analyze representative filters for fiber
background before use. Discard the filter lot if more than 4 fibers/100
fields are found.
(d) To decrease the possibility of contamination, the sampling
system (filter-backup pad-cassette) for asbestos is usually preassembled
by the manufacturer.
(e) Other cassettes, such as the Bell-mouth, may be used within the
limits of their validation.
5.1.2. Gel bands for sealing cassettes.
5.1.3. Sampling pump.
Each pump must be a battery operated, self-contained unit small
enough to be placed on the monitored employee and not interfere with the
work being performed. The pump must be capable of sampling at the
collection rate for the required sampling time.
5.1.4. Flexible tubing, 6-mm bore.
5.1.5. Pump calibration.
Stopwatch and bubble tube/burette or electronic meter.
5.2. Sampling Procedure
5.2.1. Seal the point where the base and cowl of each cassette meet
with a gel band or tape.
5.2.2. Charge the pumps completely before beginning.
5.2.3. Connect each pump to a calibration cassette with an
appropriate length of 6-mm bore plastic tubing. Do not use luer
connectors--the type of cassette specified above has built-in adapters.
5.2.4. Select an appropriate flow rate for the situation being
monitored. The sampling flow rate must be between 0.5 and 5.0 L/min for
personal sampling and is commonly set between 1 and 2 L/min. Always
choose a flow rate that will not produce overloaded filters.
5.2.5. Calibrate each sampling pump before and after sampling with a
calibration cassette in-line (Note: This calibration cassette should be
from the same lot of cassettes used for sampling). Use a primary
standard (e.g. bubble burette) to calibrate each pump. If possible,
calibrate at the sampling site.
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Note: If sampling site calibration is not possible, environmental
influences may affect the flow rate. The extent is dependent on the type
of pump used. Consult with the pump manufacturer to determine dependence
on environmental influences. If the pump is affected by temperature and
pressure changes, correct the flow rate by using the formula shown in
the section ``Sampling Pump Flow Rate Corrections'' at the end of this
appendix.
5.2.6. Connect each pump to the base of each sampling cassette with
flexible tubing. Remove the end cap of each cassette and take each air
sample open face. Assure that each sample cassette is held open side
down in the employee's breathing zone during sampling. The distance from
the nose/mouth of the employee to the cassette should be about 10 cm.
Secure the cassette on the collar or lapel of the employee using spring
clips or other similar devices.
5.2.7. A suggested minimum air volume when sampling to determine TWA
compliance is 25 L. For Excursion Limit (30 min sampling time)
evaluations, a minimum air volume of 48 L is recommended.
5.2.8. The most significant problem when sampling for asbestos is
overloading the filter with non-asbestos dust. Suggested maximum air
sample volumes for specific environments are:
------------------------------------------------------------------------
Environment Air vol. (L)
------------------------------------------------------------------------
Asbestos removal operations (visible dust).. 100
Asbestos removal operations (little dust)... 240
Office environments......................... 400 to 2,400
------------------------------------------------------------------------
Caution: Do not overload the filter with dust. High levels of non-
fibrous dust particles may obscure fibers on the filter and lower the
count or make counting impossible. If more than about 25 to 30% of the
field area is obscured with dust, the result may be biased low. Smaller
air volumes may be necessary when there is excessive non-asbestos dust
in the air.
While sampling, observe the filter with a small flashlight. If there
is a visible layer of dust on the filter, stop sampling, remove and seal
the cassette, and replace with a new sampling assembly. The total dust
loading should not exceed 1 mg.
5.2.9. Blank samples are used to determine if any contamination has
occurred during sample handling. Prepare two blanks for the first 1 to
20 samples. For sets containing greater than 20 samples, prepare blanks
as 10% of the samples. Handle blank samples in the same manner as air
samples with one exception: Do not draw any air through the blank
samples. Open the blank cassette in the place where the sample cassettes
are mounted on the employee. Hold it open for about 30 seconds. Close
and seal the cassette appropriately. Store blanks for shipment with the
sample cassettes.
5.2.10. Immediately after sampling, close and seal each cassette
with the base and plastic plugs. Do not touch or puncture the filter
membrane as this will invalidate the analysis.
5.2.11 Attach and secure a sample seal around each sample cassette
in such a way as to assure that the end cap and base plugs cannot be
removed without destroying the seal. Tape the ends of the seal together
since the seal is not long enough to be wrapped end-to-end. Also wrap
tape around the cassette at each joint to keep the seal secure.
5.3. Sample Shipment
5.3.1. Send the samples to the laboratory with paperwork requesting
asbestos analysis. List any known fibrous interferences present during
sampling on the paperwork. Also, note the workplace operation(s)
sampled.
5.3.2. Secure and handle the samples in such that they will not
rattle during shipment nor be exposed to static electricity. Do not ship
samples in expanded polystyrene peanuts, vermiculite, paper shreds, or
excelsior. Tape sample cassettes to sheet bubbles and place in a
container that will cushion the samples in such a manner that they will
not rattle.
5.3.3. To avoid the possibility of sample contamination, always ship
bulk samples in separate mailing containers.
6. Analysis
6.1. Safety Precautions
6.1.1. Acetone is extremely flammable and precautions must be taken
not to ignite it. Avoid using large containers or quantities of acetone.
Transfer the solvent in a ventilated laboratory hood. Do not use acetone
near any open flame. For generation of acetone vapor, use a spark free
heat source.
6.1.2. Any asbestos spills should be cleaned up immediately to
prevent dispersal of fibers. Prudence should be exercised to avoid
contamination of laboratory facilities or exposure of personnel to
asbestos. Asbestos spills should be cleaned up with wet methods and/or a
High Efficiency Particulate-Air (HEPA) filtered vacuum.
Caution: Do not use a vacuum without a HEPA filter--It will disperse
fine asbestos fibers in the air.
6.2. Equipment
6.2.1. Phase contrast microscope with binocular or trinocular head.
6.2.2. Widefield or Huygenian 10X eyepieces (NOTE: The eyepiece
containing the graticule must be a focusing eyepiece. Use a 40X phase
objective with a numerical aperture of 0.65 to 0.75).
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6.2.3. Kohler illumination (if possible) with green or blue filter.
6.2.4. Walton-Beckett Graticule, type G-22 with 100 2 [micro]m projected diameter.
6.2.5. Mechanical stage. A rotating mechanical stage is convenient
for use with polarized light.
6.2.6. Phase telescope.
6.2.7. Stage micrometer with 0.01-mm subdivisions.
6.2.8. Phase-shift test slide, mark II (Available from PTR optics
Ltd., and also McCrone).
6.2.9. Precleaned glass slides, 25 mmx75 mm. One end can be frosted
for convenience in writing sample numbers, etc., or paste-on labels can
be used.
6.2.10. Cover glass 1\1/2\.
6.2.11. Scalpel (10, curved blade).
6.2.12. Fine tipped forceps.
6.2.13. Aluminum block for clearing filter (see appendix D and
figure 4).
6.2.14. Automatic adjustable pipette, 100- to 500-[micro]L.
6.2.15. Micropipette, 5 [micro]L.
6.3. Reagents
6.3.1. Acetone (HPLC grade).
6.3.2. Triacetin (glycerol triacetate).
6.3.3. Lacquer or nail polish.
6.4. Standard Preparation
A way to prepare standard asbestos samples of known concentration
has not been developed. It is possible to prepare replicate samples of
nearly equal concentration. This has been performed through the PAT
program. These asbestos samples are distributed by the AIHA to
participating laboratories.
Since only about one-fourth of a 25-mm sample membrane is required
for an asbestos count, any PAT sample can serve as a ``standard'' for
replicate counting.
6.5. Sample Mounting
Note: See Safety Precautions in Section 6.1. before proceeding. The
objective is to produce samples with a smooth (non-grainy) background in
a medium with a refractive index of approximately 1.46. The technique
below collapses the filter for easier focusing and produces permanent
mounts which are useful for quality control and interlaboratory
comparison.
An aluminum block or similar device is required for sample
preparation.
6.5.1. Heat the aluminum block to about 70 [deg]C. The hot block
should not be used on any surface that can be damaged by either the heat
or from exposure to acetone.
6.5.2. Ensure that the glass slides and cover glasses are free of
dust and fibers.
6.5.3. Remove the top plug to prevent a vacuum when the cassette is
opened. Clean the outside of the cassette if necessary. Cut the seal
and/or tape on the cassette with a razor blade. Very carefully separate
the base from the extension cowl, leaving the filter and backup pad in
the base.
6.5.4. With a rocking motion cut a triangular wedge from the filter
using the scalpel. This wedge should be one-sixth to one-fourth of the
filter. Grasp the filter wedge with the forceps on the perimeter of the
filter which was clamped between the cassette pieces. DO NOT TOUCH the
filter with your finger. Place the filter on the glass slide sample side
up. Static electricity will usually keep the filter on the slide until
it is cleared.
6.5.5. Place the tip of the micropipette containing about 200
[micro]L acetone into the aluminum block. Insert the glass slide into
the receiving slot in the aluminum block. Inject the acetone into the
block with slow, steady pressure on the plunger while holding the
pipette firmly in place. Wait 3 to 5 seconds for the filter to clear,
then remove the pipette and slide from the aluminum block.
6.5.6. Immediately (less than 30 seconds) place 2.5 to 3.5 [micro]L
of triacetin on the filter (Note: Waiting longer than 30 seconds will
result in increased index of refraction and decreased contrast between
the fibers and the preparation. This may also lead to separation of the
cover slip from the slide).
6.5.7. Lower a cover slip gently onto the filter at a slight angle
to reduce the possibility of forming air bubbles. If more than 30
seconds have elapsed between acetone exposure and triacetin application,
glue the edges of the cover slip to the slide with lacquer or nail
polish.
6.5.8. If clearing is slow, warm the slide for 15 min on a hot plate
having a surface temperature of about 50 [deg]C to hasten clearing. The
top of the hot block can be used if the slide is not heated too long.
6.5.9. Counting may proceed immediately after clearing and mounting
are completed.
6.6. Sample Analysis
Completely align the microscope according to the manufacturer's
instructions. Then, align the microscope using the following general
alignment routine at the beginning of every counting session and more
often if necessary.
6.6.1. Alignment
(1) Clean all optical surfaces. Even a small amount of dirt can
significantly degrade the image.
(2) Rough focus the objective on a sample.
(3) Close down the field iris so that it is visible in the field of
view. Focus the image of the iris with the condenser focus. Center the
image of the iris in the field of view.
(4) Install the phase telescope and focus on the phase rings.
Critically center the rings. Misalignment of the rings results in
astigmatism which will degrade the image.
[[Page 150]]
(5) Place the phase-shift test slide on the microscope stage and
focus on the lines. The analyst must see line set 3 and should see at
least parts of 4 and 5 but, not see line set 6 or 6. A microscope/
microscopist combination which does not pass this test may not be used.
6.6.2. Counting Fibers
(1) Place the prepared sample slide on the mechanical stage of the
microscope. Position the center of the wedge under the objective lens
and focus upon the sample.
(2) Start counting from one end of the wedge and progress along a
radial line to the other end (count in either direction from perimeter
to wedge tip). Select fields randomly, without looking into the
eyepieces, by slightly advancing the slide in one direction with the
mechanical stage control.
(3) Continually scan over a range of focal planes (generally the
upper 10 to 15 [micro]m of the filter surface) with the fine focus
control during each field count. Spend at least 5 to 15 seconds per
field.
(4) Most samples will contain asbestos fibers with fiber diameters
less than 1 [micro]m. Look carefully for faint fiber images. The small
diameter fibers will be very hard to see. However, they are an important
contribution to the total count.
(5) Count only fibers equal to or longer than 5 [micro]m. Measure
the length of curved fibers along the curve.
(6) Count fibers which have a length to width ratio of 3:1 or
greater.
(7) Count all the fibers in at least 20 fields. Continue counting
until either 100 fibers are counted or 100 fields have been viewed;
whichever occurs first. Count all the fibers in the final field.
(8) Fibers lying entirely within the boundary of the Walton-Beckett
graticule field shall receive a count of 1. Fibers crossing the boundary
once, having one end within the circle shall receive a count of \1/2\.
Do not count any fiber that crosses the graticule boundary more than
once. Reject and do not count any other fibers even though they may be
visible outside the graticule area. If a fiber touches the circle, it is
considered to cross the line.
(9) Count bundles of fibers as one fiber unless individual fibers
can be clearly identified and each individual fiber is clearly not
connected to another counted fiber. See figure 1 for counting
conventions.
(10) Record the number of fibers in each field in a consistent way
such that filter non-uniformity can be assessed.
(11) Regularly check phase ring alignment.
(12) When an agglomerate (mass of material) covers more than 25% of
the field of view, reject the field and select another. Do not include
it in the number of fields counted.
(13) Perform a ``blind recount'' of 1 in every 10 filter wedges
(slides). Re-label the slides using a person other than the original
counter.
6.7. Fiber Identification
As previously mentioned in Section 1.3., PCM does not provide
positive confirmation of asbestos fibers. Alternate differential
counting techniques should be used if discrimination is desirable.
Differential counting may include primary discrimination based on
morphology, polarized light analysis of fibers, or modification of PCM
data by Scanning Electron or Transmission Electron Microscopy.
A great deal of experience is required to routinely and correctly
perform differential counting. It is discouraged unless it is legally
necessary. Then, only if a fiber is obviously not asbestos should it be
excluded from the count. Further discussion of this technique can be
found in reference 8.10.
If there is a question whether a fiber is asbestos or not, follow
the rule:
``WHEN IN DOUBT, COUNT.''
6.8. Analytical Recommendations--Quality Control System
6.8.1. All individuals performing asbestos analysis must have taken
the NIOSH course for sampling and evaluating airborne asbestos or an
equivalent course.
6.8.2. Each laboratory engaged in asbestos counting shall set up a
slide trading arrangement with at least two other laboratories in order
to compare performance and eliminate inbreeding of error. The slide
exchange occurs at least semiannually. The round robin results shall be
posted where all analysts can view individual analyst's results.
6.8.3. Each laboratory engaged in asbestos counting shall
participate in the Proficiency Analytical Testing Program, the Asbestos
Analyst Registry or equivalent.
6.8.4. Each analyst shall select and count prepared slides from a
``slide bank''. These are quality assurance counts. The slide bank shall
be prepared using uniformly distributed samples taken from the workload.
Fiber densities should cover the entire range routinely analyzed by the
laboratory. These slides are counted blind by all counters to establish
an original standard deviation. This historical distribution is compared
with the quality assurance counts. A counter must have 95% of all
quality control samples counted within three standard deviations of the
historical mean. This count is then integrated into a new historical
mean and standard deviation for the slide.
The analyses done by the counters to establish the slide bank may be
used for an interim quality control program if the data are treated in a
proper statistical fashion.
[[Page 151]]
7. Calculations
7.1. Calculate the estimated airborne asbestos fiber concentration
on the filter sample using the following formula:
[GRAPHIC] [TIFF OMITTED] TR10AU94.027
Where:
AC = Airborne fiber concentration
FB = Total number of fibers greater than 5 [micro]m counted
FL = Total number of fields counted on the filter
BFB = Total number of fibers greater than 5 [micro]m counted in the
blank
BFL = Total number of fields counted on the blank
ECA = Effective collecting area of filter (385 mm\2\ nominal for a 25-mm
filter.)
FR = Pump flow rate (L/min)
MFA = Microscope count field area (mm\2\ ). This is 0.00785 mm\2\ for a
Walton-Beckett Graticule.
T = Sample collection time (min)
1,000 = Conversion of L to cc
Note: The collection area of a filter is seldom equal to 385 mm\2\.
It is appropriate for laboratories to routinely monitor the exact
diameter using an inside micrometer. The collection area is calculated
according to the formula:
Area = [pi](d/2) \2\
7.2. Short-cut Calculation
Since a given analyst always has the same interpupillary distance,
the number of fields per filter for a particular analyst will remain
constant for a given size filter. The field size for that analyst is
constant (i.e. the analyst is using an assigned microscope and is not
changing the reticle).
For example, if the exposed area of the filter is always 385 mm\2\
and the size of the field is always 0.00785 mm\2\, the number of fields
per filter will always be 49,000. In addition it is necessary to convert
liters of air to cc. These three constants can then be combined such
that ECA/(1,000xMFA) = 49. The previous equation simplifies to:
[GRAPHIC] [TIFF OMITTED] TR10AU94.028
7.3. Recount Calculations
As mentioned in step 13 of Section 6.6.2., a ``blind recount'' of
10% of the slides is performed. In all cases, differences will be
observed between the first and second counts of the same filter wedge.
Most of these differences will be due to chance alone, that is, due to
the random variability (precision) of the count method. Statistical
recount criteria enables one to decide whether observed differences can
be explained due to chance alone or are probably due to systematic
differences between analysts, microscopes, or other biasing factors.
The following recount criterion is for a pair of counts that
estimate AC in fibers/cc. The criterion is given at the type-I error
level. That is, there is 5% maximum risk that we will reject a pair of
counts for the reason that one might be biased, when the large observed
difference is really due to chance.
Reject a pair of counts if:
[GRAPHIC] [TIFF OMITTED] TR29JN95.001
Where:
AC1 = lower estimated airborne fiber concentration
AC2 = higher estimated airborne fiber concentration
ACavg = average of the two concentration estimates
CVFB = CV for the average of the two concentration estimates
If a pair of counts are rejected by this criterion then, recount the
rest of the filters in the submitted set. Apply the test and reject any
other pairs failing the test. Rejection shall include a memo to the
industrial hygienist stating that the sample failed a statistical test
for homogeneity and the true air concentration may be significantly
different than the reported value.
7.4. Reporting Results
Report results to the industrial hygienist as fibers/cc. Use two
significant figures. If multiple analyses are performed on a sample, an
average of the results is to be reported unless any of the results can
be rejected for cause.
8. References
8.1. Dreesen, W.C., et al, U.S. Public Health Service: A Study of
Asbestosis in the Asbestos Textile Industry, (Public Health Bulletin No.
241), US Treasury Dept., Washington, DC, 1938.
8.2. Asbestos Research Council: The Measurement of Airborne Asbestos
Dust by the Membrane Filter Method (Technical Note), Asbestos Research
Council, Rockdale, Lancashire, Great Britain, 1969.
8.3. Bayer, S.G., Zumwalde, R.D., Brown, T.A., Equipment and
Procedure for Mounting Millipore Filters and Counting Asbestos Fibers
[[Page 152]]
by Phase Contrast Microscopy, Bureau of Occupational Health, U.S. Dept.
of Health, Education and Welfare, Cincinnati,OH,1969.
8.4. NIOSH Manual of Analytical Methods, 2nd ed., Vol. 1 (DHEW/NIOSH
Pub. No. 77-157-A). National Institute for Occupational Safety and
Health, Cincinnati, OH, 1977.pp.239-1-239-21.
8.5. Asbestos, Code of Federal Regulations 29 CFR 1910.1001. 1971.
8.6. Occupational Exposure to Asbestos, Tremolite, Anthophyllite,
and Actinolite. Final Rule, Federal Register 51: 119 (20 June 1986).
pp.22612-22790.
8.7. Asbestos, Tremolite, Anthophyllite, and Actinolite, Code of
Federal Regulations 1910.1001. 1988. pp 711-752.
8.8. Criteria for a Recommended Standard--Occupational Exposure to
Asbestos (DHEW/NIOSH Pub. No. HSM 72-10267), National Institute for
Occupational Safety and Health NIOSH, Cincinnati, OH, 1972. pp. III-1-
III-24.
8.9. Leidel, N.A., Bayer, S.G., Zumwalde, R.D., Busch, K.A., USPHS/
NIOSH Membrane Filter Method for Evaluating Airborne Asbestos Fibers
(DHEW/NIOSH Pub. No. 79-127). National Institute for Occupational Safety
and Health, Cincinnati, OH, 1979.
8.10. Dixon, W.C., Applications of Optical Microscopy in Analysis of
Asbestos and Quartz, Analytical Techniques in Occupational Health
Chemistry, edited by D.D. Dollberg and A.W. Verstuyft. Wash. D.C.:
American Chemical Society, (ACS Symposium Series 120) 1980. pp. 13-41.
Quality Control
The OSHA asbestos regulations require each laboratory to establish a
quality control program. The following is presented as an example of how
the OSHA-SLTC constructed its internal CV curve as part of meeting this
requirement. Data is from 395 samples collected during OSHA compliance
inspections and analyzed from October 1980 through April 1986.
Each sample was counted by 2 to 5 different counters independently
of one another. The standard deviation and the CV statistic was
calculated for each sample. This data was then plotted on a graph of CV
vs. fibers/mm\2\. A least squares regression was performed using the
following equation:
CV =
antilog10[A(log10(x))\2\+B(log10(x))+C]
Where:
x = the number of fibers/mm\2\
Application of least squares gave:
A = 0.182205
B = -0.973343
C = 0.327499
Using these values, the equation becomes:
CV = antilog10[0.182205(log10 (x))\2\-0.973343(log
10(x))+0.327499]
Sampling Pump Flow Rate Corrections
This correction is used if a difference greater than 5% in ambient
temperature and/or pressure is noted between calibration and sampling
sites and the pump does not compensate for the differences.
[GRAPHIC] [TIFF OMITTED] TR10AU94.030
Where:
Qact = actual flow rate
Qcal = calibrated flow rate (if a rotameter was used, the
rotameter value)
Pcal = uncorrected air pressure at calibration
Pact = uncorrected air pressure at sampling site
Tact = temperature at sampling site (K)
Tcal = temperature at calibration (K)
Walton-Beckett Graticule
When ordering the Graticule for asbestos counting, specify the exact
disc diameter needed to fit the ocular of the microscope and the
diameter (mm) of the circular counting area. Instructions for measuring
the dimensions necessary are listed:
(1) Insert any available graticule into the focusing eyepiece and
focus so that the graticule lines are sharp and clear.
(2) Align the microscope.
(3) Place a stage micrometer on the microscope object stage and
focus the microscope on the graduated lines.
(4) Measure the magnified grid length, PL ([micro]m), using the
stage micrometer.
(5) Remove the graticule from the microscope and measure its actual
grid length, AL (mm). This can be accomplished by using a mechanical
stage fitted with verniers, or a jeweler's loupe with a direct reading
scale.
(6) Let D=100 [micro]m. Calculate the circle diameter, dc
(mm), for the Walton-Beckett graticule and specify the diameter when
making a purchase:
[GRAPHIC] [TIFF OMITTED] TR10AU94.031
Example: If PL=108 [micro]m, AL=2.93 mm and D=100 [micro]m, then,
[GRAPHIC] [TIFF OMITTED] TR10AU94.032
(7) Each eyepiece-objective-reticle combination on the microscope
must be calibrated. Should any of the three be changed (by zoom
adjustment, disassembly, replacement, etc.), the combination must be
recalibrated. Calibration may change if interpupillary distance is
changed.
[[Page 153]]
Measure the field diameter, D (acceptable range: 100 2 [micro]m) with a stage micrometer upon receipt of the
graticule from the manufacturer. Determine the field area (mm\2\).
Field Area= [pi](D/2)\2\
If D=100 [micro]m=0.1 mm, then
Field Area=[pi](0.1 mm/2)\2\=0.00785 mm\2\
The Graticule is available from: Graticules Ltd., Morley Road,
Tonbridge TN9 IRN, Kent, England (Telephone 011-44-732-359061). Also
available from PTR Optics Ltd., 145 Newton Street, Waltham, MA 02154
[telephone (617) 891-6000] or McCrone Accessories and Components, 2506
S. Michigan Ave., Chicago, IL 60616 [phone (312) 842-7100]. The
graticule is custom made for each microscope.
[GRAPHIC] [TIFF OMITTED] TR10AU94.008
Counts for the Fibers in the Figure
------------------------------------------------------------------------
Structure No. Count Explanation
------------------------------------------------------------------------
1 to 6....................... 1 Single fibers all contained
within the circle.
7............................ \1/2\ Fiber crosses circle once.
8............................ 0 Fiber too short.
9............................ 2 Two crossing fibers.
10........................... 0 Fiber outside graticule.
11........................... 0 Fiber crosses graticule twice.
12........................... \1/2\ Although split, fiber only
crosses once.
------------------------------------------------------------------------
[[Page 154]]
Appendix C to Sec. 1915.1001--Qualitative and Quantitative Fit Testing
Procedures. Mandatory
Qualitative Fit Test Protocols
I. Isoamyl Acetate Protocol
A. Odor threshold screening. 1. Three 1-liter glass jars with metal
lids (e.g. Mason or Bell jars) are required.
2. Odor-free water (e.g. distilled or spring water) at approximately
25 [deg]C shall be used for the solutions.
3. The isoamyl acetate (IAA) (also known as isopentyl acetate) stock
solution is prepared by adding 1 cc of pure IAA to 800 cc of odor free
water in a 1-liter jar and shaking for 30 seconds. This solution shall
be prepared new at least weekly.
4. The screening test shall be conducted in a room separate from the
room used for actual fit testing. The two rooms shall be well ventilated
but shall not be connected to the same recirculating ventilation system.
5. The odor test solution is prepared in a second jar by placing 0.4
cc of the stock solution into 500 cc of odor free water using a clean
dropper or pipette. Shake for 30 seconds and allow to stand for two to
three minutes so that the IAA concentration above the liquid may reach
equilibrium. This solution may be used for only one day.
6. A test blank is prepared in a third jar by adding 500 cc of odor
free water.
7. The odor test and test blank jars shall be labelled 1 and 2 for
jar identification. If the labels are put on the lids they can be
periodically peeled, dried off and switched to maintain the integrity of
the test.
8. The following instructions shall be typed on a card and placed on
the table in front of the two test jars (i.e. 1 and 2): ``The purpose of
this test is to determine if you can smell banana oil at a low
concentration. The two bottles in front of you contain water. One of
these bottles also contains a small amount of banana oil. Be sure the
covers are on tight, then shake each bottle for two seconds. Unscrew the
lid of each bottle, one at a time, and sniff at the mouth of the bottle.
Indicate to the test conductor which bottle contains banana oil.''
9. The mixtures used in the IAA odor detection test shall be
prepared in an area separate from where the test is performed, in order
to prevent olfactory fatigue in the subject.
10. If the test subject is unable to correctly identify the jar
containing the odor test solution, the IAA qualitative fit test may not
be used.
11. If the test subject correctly identifies the jar containing the
odor test solution, the test subject may proceed to respirator selection
and fit testing.
B. Respirator Selection. 1. The test subject shall be allowed to
pick the most comfortable respirator from a selection including
respirators of various sizes from different manufacturers. The selection
shall include at least five sizes of elastomeric half facepieces, from
at least two manufacturers.
2. The selection process shall be conducted in a room separate from
the fit-test chamber to prevent odor fatigue. Prior to the selection
process, the test subject shall be shown how to put on a respirator, how
it should be positioned on the face, how to set strap tension and how to
determine a ``comfortable'' respirator. A mirror shall be available to
assist the subject in evaluating the fit and positioning of the
respirator. This instruction may not constitute the subject's formal
training on respirator use, as it is only a review.
3. The test subject should understand that the employee is being
asked to select the respirator which provides the most comfortable fit.
Each respirator represents a different size and shape and, if fit
properly and used properly will provide adequate protection.
4. The test subject holds each facepiece up to the face and
eliminates those which obviously do not give a comfortable fit.
Normally, selection will begin with a half-mask and if a good fit cannot
be found, the subject will be asked to test the full facepiece
respirators. (A small percentage of users will not be able to wear any
half-mask.)
5. The more comfortable facepieces are noted; the most comfortable
mask is donned and worn at least five minutes to assess comfort. All
donning and adjustments of the facepiece shall be performed by the test
subject without assistance from the test conductor or other person.
Assistance in assessing comfort can be given by discussing the points in
6 below. If the test subject is not familiar with using a
particular respirator, the test subject shall be directed to don the
mask several times and to adjust the straps each time to become adept at
setting proper tension on the straps.
6. Assessment of comfort shall include reviewing the following
points with the test subject and allowing the test subject adequate time
to determine the comfort of the respirator:
Positioning of mask on nose.
Room for eye protection.
Room to talk.
Positioning mask on face and cheeks.
7. The following criteria shall be used to help determine the
adequacy of the respirator fit:
Chin properly placed.
Strap tension.
Fit across nose bridge.
Distance from nose to chin.
Tendency to slip.
Self-observation in mirror.
8. The test subject shall conduct the conventional negative and
positive-pressure fit
[[Page 155]]
checks (e.g. see ANSI Z88.2-1980). Before conducting the negative- or
positive-pressure test the subject shall be told to ``seat'' the mask by
rapidly moving the head from side-to-side and up and down, while taking
a few deep breaths.
9. The test subject is now ready for fit testing.
10. After passing the fit test, the test subject shall be questioned
again regarding the comfort of the respirator. If it has become
uncomfortable, another model of respirator shall be tried.
11. The employee shall be given the opportunity to select a
different facepiece and be retested if the chosen facepiece becomes
increasingly uncomfortable at any time.
C. Fit test. 1. The fit test chamber shall be similar to a clear 55
gal drum liner suspended inverted over a 2 foot diameter frame, so that
the top of the chamber is about 6 inches above the test subject's head.
The inside top center of the chamber shall have a small hook attached.
2. Each respirator used for the fitting and fit testing shall be
equipped with organic vapor cartridges or offer protection against
organic vapors. The cartridges or masks shall be changed at least
weekly.
3. After selecting, donning, and properly adjusting a respirator,
the test subject shall wear it to the fit testing room. This room shall
be separate from the room used for odor threshold screening and
respirator selection, and shall be well ventilated, as by an exhaust fan
or lab hood, to prevent general room contamination.
4. A copy of the following test exercises and rainbow passage shall
be taped to the inside of the test chamber:
Test Exercises
i. Breathe normally.
ii. Breathe deeply. Be certain breaths are deep and regular.
iii. Turn head all the way from one side to the other. Inhale on
each side. Be certain movement is complete. Do not bump the respirator
against the shoulders.
iv. Nod head up-and-down. Inhale when head is in the full up
position (looking toward ceiling). Be certain motions are complete and
made about every second. Do not bump the respirator on the chest.
v. Talking. Talk aloud and slowly for several minutes. The following
paragraph is called the Rainbow Passage. Reading it will result in a
wide range of facial movements, and thus be useful to satisfy this
requirement. Alternative passages which serve the same purpose may also
be used.
vi. Jogging in place.
vii. Breathe normally.
Rainbow Passage
When the sunlight strikes raindrops in the air, they act like a
prism and form a rainbow. The rainbow is a division of white light into
many beautiful colors. These take the shape of a long round arch, with
its path high above, and its two ends apparently beyond the horizon.
There is, according to legend, a boiling pot of gold at one end. People
look, but no one ever finds it. When a man looks for something beyond
reach, his friends say he is looking for the pot of gold at the end of
the rainbow.
5. Each test subject shall wear the respirator for at a least 10
minutes before starting the fit test.
6. Upon entering the test chamber, the test subject shall be given a
6 inch by 5 inch piece of paper towel or other porous absorbent single
ply material, folded in half and wetted with three-quarters of one cc of
pure IAA. The test subject shall hang the wet towel on the hook at the
top of the chamber.
7. Allow two minutes for the IAA test concentration to be reached
before starting the fit-test exercises. This would be an appropriate
time to talk with the test subject, to explain the fit test, the
importance of cooperation, the purpose for the head exercises, or to
demonstrate some of the exercises.
8. Each exercise described in 4 above shall be performed
for at least one minute.
9. If at any time during the test, the subject detects the banana-
like odor of IAA, the test has failed. The subject shall quickly exit
from the test chamber and leave the test area to avoid olfactory
fatigue.
10. If the test is failed, the subject shall return to the selection
room and remove the respirator, repeat the odor sensitivity test, select
and put on another respirator, return to the test chamber, and again
begin the procedure described in the c(4) through c(8) above. The
process continues until a respirator that fits well has been found.
Should the odor sensitivity test be failed, the subject shall wait about
5 minutes before retesting. Odor sensitivity will usually have returned
by this time.
11. If a person cannot pass the fit test described above wearing a
half-mask respirator from the available selection, full facepiece models
must be used.
12. When a respirator is found that passes the test, the subject
breaks the faceseal and takes a breath before exiting the chamber. This
is to assure that the reason the test subject is not smelling the IAA is
the good fit of the respirator facepiece seal and not olfactory fatigue.
13. When the test subject leaves the chamber, the subject shall
remove the saturated towel and return it to the person conducting the
test. To keep the area from becoming contaminated, the used towels shall
be kept in a self-sealing bag so there is no significant
[[Page 156]]
IAA concentration buildup in the test chamber during subsequent tests.
14. At least two facepieces shall be selected for the IAA test
protocol. The test subject shall be given the opportunity to wear them
for one week to choose the one which is more comfortable to wear.
15. Persons who have successfully passed this fit test with a half-
mask respirator may be assigned the use of the test respirator in
atmospheres with up to 10 times the PEL of airborne asbestos. In
atmospheres greater than 10 times, and less than 100 times the PEL (up
to 100 ppm), the subject must pass the IAA test using a full face
negative pressure respirator. (The concentration of the 1AA inside the
test chamber must be increased by ten times for QLFT of the full
facepiece.)
16. The test shall not be conducted if there is any hair growth
between the skin the facepiece sealing surface.
17. If hair growth or apparel interfere with a satisfactory fit,
then they shall be altered or removed so as to eliminate interference
and allow a satisfactory fit. If a satisfactory fit is still not
attained, the test subject must use a positive-pressure respirator such
as powered air-purifying respirators, supplied air respirator, or self-
contained breathing apparatus.
18. If a test subject exhibits difficulty in breathing during the
tests, she or he shall be referred to a physician trained in respirator
diseases or pulmonary medicine to determine whether the test subject can
wear a respirator while performing her or his duties.
19. Qualitative fit testing shall be repeated at least every six
months.
20. In addition, because the sealing of the respirator may be
affected, qualitative fit testing shall be repeated immediately when the
test subject has a:
(1) Weight change of 20 pounds or more,
(2) Significant facial scarring in the area of the facepiece seal,
(3) Significant dental changes; i.e.; multiple extractions without
prothesis, or acquiring dentures,
(4) Reconstructive or cosmetic surgery, or
(5) Any other condition that may interfere with facepiece sealing.
D. Recordkeeping. A summary of all test results shall be maintained
in each office for 3 years. The summary shall include:
(1) Name of test subject.
(2) Date of testing.
(3) Name of the test conductor.
(4) Respirators selected (indicate manufacturer, model, size and
approval number).
(5) Testing agent.
II. Saccharin Solution Aerosol Protocol
A. Respirator selection. Respirators shall be selected as described
in section IB (respirator selection) above, except that each respirator
shall be equipped with a particulate filter.
B. Taste Threshold Screening
1. An enclosure about head and shoulders shall be used for threshold
screening (to determine if the individual can taste saccharin) and for
fit testing. The enclosure shall be approximately 12 inches in diameter
by 14 inches tall with at least the front clear to allow free movement
of the head when a respirator is worn.
2. The test enclosure shall have a three-quarter inch hole in front
of the test subject's nose and mouth area to accommodate the nebulizer
nozzle.
3. The entire screening and testing procedure shall be explained to
the test subject prior to conducting the screening test.
4. During the threshold screening test, the test subject shall don
the test enclosure and breathe with open mouth with tongue extended.
5. Using a DeVilbiss Model 40 Inhalation Medication Nebulizer or
equivalent, the test conductor shall spray the threshold check solution
into the enclosure. This nebulizer shall be clearly marked to
distinguish it from the fit test solution nebulizer.
6. The threshold check solution consists of 0.83 grams of sodium
saccharin, USP in water. It can be prepared by putting 1 cc of the test
solution (see C 7 below) in 100 cc of water.
7. To produce the aerosol, the nebulizer bulb is firmly squeezed so
that it collapses completely, then is released and allowed to fully
expand.
8. Ten squeezes of the nebulizer bulb are repeated rapidly and then
the test subject is asked whether the saccharin can be tasted.
9. If the first response is negative, ten more squeezes of the
nebulizer bulb are repeated rapidly and the test subject is again asked
whether the saccharin can be tasted.
10. If the second response is negative ten more squeezes are
repeated rapidly and the test subject is again asked whether the
saccharin can be tasted.
11. The test conductor will take note of the number of squeezes
required to elicit a taste response.
12. If the saccharin is not tasted after 30 squeezes (Step 10), the
saccharin fit test cannot be performed on the test subject.
13. If a taste response is elicited, the test subject shall be asked
to take note of the taste for reference in the fit test.
14. Correct use of the nebulizer means that approximately 1 cc of
liquid is used at a time in the nebulizer body.
15. The nebulizer shall be thoroughly rinsed in water, shaken dry,
and refilled at least every four hours.
C. Fit test. 1. The test subject shall don and adjust the respirator
without the assistance from any person.
[[Page 157]]
2. The fit test uses the same enclosure described in IIB above.
3. Each test subject shall wear the respirator for a least 10
minutes before starting the fit test.
4. The test subject shall don the enclosure while wearing the
respirator selected in section IB above. This respirator shall be
properly adjusted and equipped with a particulate filter.
5. The test subject may not eat, drink (except plain water), or chew
gum for 15 minutes before the test.
6. A second DeVilbiss Model 40 Inhalation Medication Nebulizer is
used to spray the fit test solution into the enclosure. This nebulizer
shall be clearly marked to distinguish it from the screening test
solution nebulizer.
7. The fit test solution is prepared by adding 83 grams of sodium
saccharin to 100 cc of warm water.
8. As before, the test subject shall breathe with mouth open and
tongue extended.
9. The nebulizer is inserted into the hole in the front of the
enclosure and the fit test solution is sprayed into the enclosure using
the same technique as for the taste threshold screening and the same
number of squeezes required to elicit a taste response in the screening.
(See B8 through B10 above).
10. After generation of the aerosol read the following instructions
to the test subject. The test subject shall perform the exercises for
one minute each.
i. Breathe normally.
ii. Breathe deeply. Be certain breaths are deep and regular.
iii. Turn head all the way from one side to the other. Be certain
movement is complete. Inhale on each side. Do not bump the respirator
against the shoulders.
iv. Nod head up-and-down. Be certain motions are complete. Inhale
when head is in the full up position (when looking toward the ceiling).
Do not to bump the respirator on the chest.
v. Talking. Talk aloud and slowly for several minutes. The following
paragraph is called the Rainbow Passage. Reading it will result in a
wide range of facial movements, and thus be useful to satisfy this
requirement. Alternative passages which serve the same purpose may also
be used.
vi. Jogging in place.
vii. Breathe normally.
Rainbow Passage
When the sunlight strikes raindrops in the air, they act like a
prism and form a rainbow. The rainbow is a division of white light into
many beautiful colors. These take the shape of a long round arch, with
its path high above, and its two ends apparently beyond the horizon.
There is, according to legend, a boiling pot of gold at one end. People
look, but no one ever finds it. When a man looks for something beyond
his reach, his friends say he is looking for the pot of gold at the end
of the rainbow.
11. At the beginning of each exercise, the aerosol concentration
shall be replenished using one-half the number of squeezes as initially
described in C9.
12. The test subject shall indicate to the test conductor if at any
time during the fit test the taste of saccharin is detected.
13. If the saccharin is detected the fit is deemed unsatisfactory
and a different respirator shall be tried.
14. At least two facepieces shall be selected by the IAA test
protocol. The test subject shall be given the opportunity to wear them
for one week to choose the one which is more comfortable to wear.
15. Successful completion of the test protocol shall allow the use
of the half mask tested respirator in contaminated atmospheres up to 10
times the PEL of asbestos. In other words this protocol may be used to
assign protection factors no higher than ten.
16. The test shall not be conducted if there is any hair growth
between the skin and the facepiece sealing surface.
17. If hair growth or apparel interfere with a satisfactory fit,
then they shall be altered or removed so as to eliminate interference
and allow a satisfactory fit. If a satisfactory fit is still not
attained, the test subject must use a positive-pressure respirator such
as powered air-purifying respirators, supplied air respirator, or self-
contained breathing apparatus.
18. If a test subject exhibits difficulty in breathing during the
tests, she or he shall be referred to a physician trained in respirator
diseases or pulmonary medicine to determine whether the test subject can
wear a respirator while performing her or his duties.
19. Qualitative fit testing shall be repeated at least every six
months.
20. In addition, because the sealing of the respirator may be
affected, qualitative fit testing shall be repeated immediately when the
test subject has a:
(1) Weight change of 20 pounds or more,
(2) Significant facial scarring in the area of the facepiece seal,
(3) Significant dental changes; i.e.; multiple extractions without
prothesis, or acquiring dentures,
(4) Reconstructive or cosmetic surgery, or
(5) Any other condition that may interfere with facepiece sealing.
D. Recordkeeping. A summary of all test results shall be maintained
in each office for 3 years. The summary shall include:
(1) Name of test subject
(2) Date of testing.
(3) Name of test conductor.
(4) Respirators selected (indicate manufacturer, model, size and
approval number).
(5) Testing agent.
[[Page 158]]
III. Irritant Fume Protocol
A. Respirator selection. Respirators shall be selected as described
in section IB above, except that each respirator shall be equipped with
a combination of high-efficiency and acid-gas cartridges.
B. Fit test. 1. The test subject shall be allowed to smell a weak
concentration of the irritant smoke to familiarize the subject with the
characteristic odor.
2. The test subject shall properly don the respirator selected as
above, and wear it for at least 10 minutes before starting the fit test.
3. The test conductor shall review this protocol with the test
subject before testing.
4. The test subject shall perform the conventional positive pressure
and negative pressure fit checks (see ANSI Z88.2 1980). Failure of
either check shall be cause to select an alternate respirator.
5. Break both ends of a ventilation smoke tube containing stannic
oxychloride, such as the MSA part 5645, or equivalent. Attach a
short length of tubing to one end of the smoke tube. Attach the other
end of the smoke tube to a low pressure air pump set to deliver 200
milliliters per minute.
6. Advise the test subject that the smoke can be irritating to the
eyes and instruct the subject to keep the eyes closed while the test is
performed.
7. The test conductor shall direct the stream of irritant smoke from
the tube towards the faceseal area of the test subject. The person
conducting the test shall begin with the tube at least 12 inches from
the facepiece and gradually move to within one inch, moving around the
whole perimeter of the mask.
8. The test subject shall be instructed to do the following
exercises while the respirator is being challenged by the smoke. Each
exercise shall be performed for one minute.
i. Breathe normally.
ii. Breathe deeply. Be certain breaths are deep and regular.
iii. Turn head all the way from one side to the other. Be certain
movement is complete. Inhale on each side. Do not bump the respirator
against the shoulders.
iv. Nod head up-and-down. Be certain motions are complete and made
every second. Inhale when head is in the full up position (looking
toward ceiling). Do not bump the respirator against the chest.
v. Talking. Talk aloud and slowly for several minutes. The following
paragraph is called the Rainbow Passage. Reading it will result in a
wide range of facial movements, and thus be useful to satisfy this
requirement. Alternative passages which serve the same purpose may also
be used.
Rainbow Passage
When the sunlight strikes raindrops in the air, they act like a
prism and form a rainbow. The rainbow is a division of white light into
many beautiful colors. These take the shape of a long round arch, with
its path high above, and its two end apparently beyond the horizon.
There is, according to legend, a boiling pot of gold at one end. People
look, but no one ever finds it. When a man looks for something beyond
his reach, his friends say he is looking for the pot of gold at the end
of the rainbow.
vi. Jogging in Place.
vii. Breathe normally.
9. The test subject shall indicate to the test conductor if the
irritant smoke is detected. If smoke is detected, the test conductor
shall stop the test. In this case, the tested respirator is rejected and
another respirator shall be selected.
10. Each test subject passing the smoke test (i.e. without detecting
the smoke) shall be given a sensitivity check of smoke from the same
tube to determine if the test subject reacts to the smoke. Failure to
evoke a response shall void the fit test.
11. Steps B4, B9, B10 of this fit test protocol shall be performed
in a location with exhaust ventilation sufficient to prevent general
contamination of the testing area by the test agents.
12. At least two facepieces shall be selected by the IAA test
protocol. The test subject shall be given the opportunity to wear them
for one week to choose the one which is more comfortable to wear.
13. Respirators successfully tested by the protocol may be used in
contaminated atmospheres up to ten times the PEL of asbestos.
14. The test shall not be conducted if there is any hair growth
between the skin and the facepiece sealing surface.
15. If hair growth or apparel interfere with a satisfactory fit,
then they shall be altered or removed so as to eliminate interference
and allow a satisfactory fit. If a satisfactory fit is still not
attained, the test subject must use a positive-pressure respirator such
as powered air-purifying respirators, supplied air respirator, or self-
contained breathing apparatus.
16. If a test subject exhibits difficulty in breathing during the
tests, she or he shall be referred to a physician trained in respirator
diseases or pulmonary medicine to determine whether the test subject can
wear a respirator while performing her or his duties.
17. Qualitative fit testing shall be repeated at least every six
months.
18. In addition, because the sealing of the respirator may be
affected, qualitative fit testing shall be repeated immediately when the
test subject has a:
(1) Weight change of 20 pounds or more,
[[Page 159]]
(2) Significant facial scarring in the area of the facepiece seal,
(3) Significant dental changes; i.e.; multiple extractions without
prothesis, or acquiring dentures,
(4) Reconstructive or cosmetic surgery, or
(5) Any other condition that may interfere with facepiece sealing.
D. Recordkeeping. A summary of all test results shall be maintained
in each office for 3 years. The summary shall include:
(1) Name of test subject
(2) Date of testing.
(3) Name of test conductor.
(4) Respirators selected (indicate manufacturer, model, size and
approval number).
(5) Testing agent
Quantitative Fit Test Procedures
1. General
a. The method applies to negative-pressure non-powered air-purifying
respirators only.
b. The employer shall assign one individual who shall assume the
full responsibility for implementing the respirator quantitative fit
test program.
2. Definition
a. ``Quantitative Fit Test'' means the measurement of the
effectiveness of a respirator seal in excluding the ambient atmosphere.
The test is performed by dividing the measured concentration of
challenge agent in a test chamber by the measured concentration of the
challenge agent inside the respirator facepiece when the normal air
purifying element has been replaced by an essentially perfect purifying
element.
b. ``Challenge Agent'' means the air contaminant introduced into a
test chamber so that its concentration inside and outside the respirator
may be compared.
c. ``Test Subject'' means the person wearing the respirator for
quantitative fit testing.
d. ``Normal Standing Position'' means standing erect and straight
with arms down along the sides and looking straight ahead.
e. ``Fit Factor'' means the ratio of challenge agent concentration
outside with respect to the inside of a respirator inlet covering
(facepiece or enclosure).
3. Apparatus
a. Instrumentation. Corn oil, sodium chloride or other appropriate
aerosol generation, dilution, and measurement systems shall be used for
quantitative fit test.
b. Test chamber. The test chamber shall be large enough to permit
all test subjects to freely perform all required exercises without
distributing the challenge agent concentration or the measurement
apparatus. The test chamber shall be equipped and constructed so that
the challenge agent is effectively isolated from the ambient air yet
uniform in concentration throughout the chamber.
c. When testing air-purifying respirators, the normal filter or
cartridge element shall be replaced with a high-efficiency particular
filter supplied by the same manufacturer.
d. The sampling instrument shall be selected so that a strip chart
record may be made of the test showing the rise and fall of challenge
agent concentration with each inspiration and expiration at fit factors
of at least 2,000.
e. The combination of substitute air-purifying elements (if any),
challenge agent, and challenge agent concentration in the test chamber
shall be such that the test subject is not exposed in excess of PEL to
the challenge agent at any time during the testing process.
f. The sampling port on the test specimen respirator shall be placed
and constructed so that there is no detectable leak around the port, a
free air flow is allowed into the sampling line at all times and so
there is no interference with the fit or performance of the respirator.
g. The test chamber and test set-up shall permit the person
administering the test to observe one test subject inside the chamber
during the test.
h. The equipment generating the challenge atmosphere shall maintain
the concentration of challenge agent constant within a 10 percent
variation for the duration of the test.
i. The time lag (interval between an event and its being recorded on
the strip chart) of the instrumentation may not exceed 2 seconds.
j. The tubing for the test chamber atmosphere and for the respirator
sampling port shall be the same diameter, length and material. It shall
be kept as short as possible. The smallest diameter tubing recommended
by the manufacturer shall be used.
k. The exhaust flow from the test chamber shall pass through a high-
efficiency filter before release to the room.
l. When sodium chloride aerosol is used, the relative humidity
inside the test chamber shall not exceed 50 percent.
4. Procedural Requirements
a. The fitting of half-mask respirators should be started with those
having multiple sizes and a variety of interchangeable cartridges and
canisters such as the MSA Comfo II-M, Norton M, Survivair M, A-O M, or
Scott-M. Use either of the tests outlined below to assure that the
facepiece is properly adjusted.
(1) Positive pressure test. With the exhaust port(s) blocked, the
negative pressure of slight inhalation should remain constant for
several seconds.
(2) Negative pressure test. With the intake port(s) blocked, the
negative pressure slight
[[Page 160]]
inhalation should remain constant for several seconds.
b. After a facepiece is adjusted, the test subject shall wear the
facepiece for at least 5 minutes before conducting a qualitative test by
using either of the methods described below and using the exercise
regime described in 5.a., b., c., d. and e.
(1) Isoamyl acetate test. When using organic vapor cartridges, the
test subject who can smell the odor should be unable to detect the odor
of isoamyl acetate squirted into the air near the most vulnerable
portions of the facepiece seal. In a location which is separated from
the test area, the test subject shall be instructed to close her/his
eyes during the test period. A combination cartridge or canister with
organic vapor and high-efficiency filters shall be used when available
for the particular mask being tested. The test subject shall be given an
opportunity to smell the odor of isoamyl acetate before the test is
conducted.
(2) Irritant fume test. When using high-efficiency filters, the test
subject should be unable to detect the odor of irritant fume (stannic
chloride or titanium tetrachloride ventilation smoke tubes) squirted
into the air near the most vulnerable portions of the facepiece seal.
The test subject shall be instructed to close her/his eyes during the
test period.
c. The test subject may enter the quantitative testing chamber only
if she or he has obtained a satisfactory fit as stated in 4.b. of this
appendix.
d. Before the subject enters the test chamber, a reasonably stable
challenge agent concentration shall be measured in the test chamber.
e. Immediately after the subject enters the test chamber, the
challenge agent concentration inside the respirator shall be measured to
ensure that the peak penetration does not exceed 5 percent for a half-
mask and 1 percent for a full facepiece.
f. A stable challenge agent concentration shall be obtained prior to
the actual start of testing.
1. Respirator restraining straps may not be over-tightened for
testing. The straps shall be adjusted by the wearer to give a reasonably
comfortable fit typical of normal use.
5. Exercise Regime.
Prior to entering the test chamber, the test subject shall be given
complete instructions as to her/his part in the test procedures. The
test subject shall perform the following exercises, in the order given,
for each independent test.
a. Normal Breathing (NB). In the normal standing position, without
talking, the subject shall breathe normally for at least one minute.
b. Deep Breathing (DB). In the normal standing position the subject
shall do deep breathing for at least one minute pausing so as not to
hyperventilate.
c. Turning head side to side (SS). Standing in place the subject
shall slowly turn his/her head from side between the extreme positions
to each side. The head shall be held at each extreme position for at
least 5 seconds. Perform for at least three complete cycles.
d. Moving head up and down (UD). Standing in place, the subject
shall slowly move his/her head up and down between the extreme position
straight up and the extreme position straight down. The head shall be
held at each extreme position for at least 5 seconds. Perform for at
least three complete cycles.
e. Reading (R). The subject shall read out slowly and loud so as to
be heard clearly by the test conductor or monitor. The test subject
shall read the ``rainbow passage'' at the end of this section.
f. Grimace (G). The test subject shall grimace, smile, frown, and
generally contort the face using the facial muscles. Continue for at
least 15 seconds.
g. Bend over and touch toes (B). The test subject shall bend at the
waist and touch toes and return to upright position. Repeat for at least
30 seconds.
h. Jogging in place (J). The test subject shall perform jog in place
for at least 30 seconds.
i. Normal Breathing (NB). Same as exercise a.
Rainbow Passage
When the sunlight strikes raindrops in the air, they act like a
prism and form a rainbow. The rainbow is a division of white light into
many beautiful colors. These take the shape of a long round arch, with
its path high above, and its two ends apparently beyond the horizon.
There is, according to legend, a boiling pot of gold at one end. People
look, but no one ever finds it. When a man looks for something beyond
reach, his friends say he is looking for the pot of gold at the end of
the rainbow.
6. Test Termination.
The test shall be terminated whenever any single peak penetration
exceeds 5 percent for half-masks and 1 percent for full facepieces. The
test subject may be refitted and retested. If two of the three required
tests are terminated, the fit shall be deemed inadequate. (See paragraph
4.h)
6. The test shall be terminated whenever any single peak penetration
exceeds 5 percent for half-masks and 1 percent for full facepieces. The
test subject may be refitted and retested. If two the three required
tests are terminated, the fit shall be deemed inadequate. (See paragraph
4.h.).
[[Page 161]]
7. Calculation of Fit Factors
a. The fit factor determined by the quantitative fit test equals the
average concentration inside the respirator.
b. The average test chamber concentration is the arithmetic average
of the test chamber concentration at the beginning and of the end of the
test.
c. The average peak concentration of the challenge agent inside the
respirator shall be the arithmetic average peak concentrations for each
of the nine exercises of the test which are computed as the arithmetic
average of the peak concentrations found for each breath during the
exercise.
d. The average peak concentration for an exercise may be determined
graphically if there is not a great variation in the peak concentrations
during a single exercise.
8. Interpretation of Test Results.
The fit factor measured by the quantitative fit testing shall be the
lowest of the three protection factors resulting from three independent
tests.
9. Other Requirements
a. The test subject shall not be permitted to wear a half-mask or
full facepiece mask if the minimum fit factor of 100 or 1,000,
respectively, cannot be obtained. If hair growth or apparel interfere
with a satisfactory fit, then they shall be altered or removed so as to
eliminate interference and allow a satisfactory fit. If a satisfactory
fit is still not attained, the test subject must use a positive-pressure
respirator such as powered air-purifying respirators, supplied air
respirator, or self-contained breathing apparatus.
b. The test shall not be conducted if there is any hair growth
between the skin and the facepiece sealing surface.
c. If a test subject exhibits difficulty in breathing during the
tests, she or he shall be referred to a physician trained in respirator
diseases or pulmonary medicine to determine whether the test subject can
wear a respirator while performing her or his duties.
d. The test subject shall be given the opportunity to wear the
assigned respirator for one week. If the respirator does not provide a
satisfactory fit during actual use, the test subject may request another
QNFT which shall be performed immediately.
e. A respirator fit factor card shall be issued to the test subject
with the following information:
(1) Name
(2) Date of fit test.
(3) Protection factors obtained through each manufacturer, model and
approval number of respirator tested.
(4) Name and signature of the person that conducted the test.
f. Filters used for qualitative or quantitative fit testing shall be
replaced weekly, whenever increased breathing resistance is encountered,
or when the test agent has altered the integrity of the filter media.
Organic vapor cartridges/canisters shall be replaced daily or sooner if
there is any indication of breakthrough by the test agent.
10. In addition, because the sealing of the respirator may be
affected, quantitative fit testing shall be repeated immediately when
the test subject has a:
(1) Weight change of 20 pounds or more,
(2) Significant facial scarring in the area of the facepiece seal,
(3) Significant dental changes; i.e.; multiple extractions without
prothesis, or acquiring dentures,
(4) Reconstructive or cosmetic surgery, or
(5) Any other condition that may interfere with facepiece sealing.
11. Recordkeeping
A summary of all test results shall be maintained in for 3 years.
The summary shall include:
(1) Name of test subject
(2) Date of testing.
(3) Name of the test conductor.
(4) Fit factors obtained from every respirator tested (indicate
manufacturer, model, size and approval number).
Appendix D to Sec. 1915.1001--Medical Questionnaires. Mandatory
This mandatory appendix contains the medical questionnaires that
must be administered to all employees who are exposed to asbestos,
tremolite, anthophyllite, actinolite, or a combination of these minerals
above the permissible exposure limit (0.1 f/cc), and who will therefore
be included in their employer's medical surveillance program. Part 1 of
the appendix contains the Initial Medical Questionnaire, which must be
obtained for all new hires who will be covered by the medical
surveillance requirements. Part 2 includes the abbreviated Periodical
Medical Questionnaire, which must be administered to all employees who
are provided periodic medical examinations under the medical
surveillance provisions of the standard.
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Appendix E to Sec. 1915.1001--Interpret ation and Classification of
Chest Roentgenograms. Mandatory
(a) Chest roentgenograms shall be interpreted and classified in
accordance with a professionally accepted classification system and
recorded on an interpretation form following the format of the CDC/NIOSH
(M) 2.8 form. As a minimum, the content within the bold lines of this
form (items 1 through 4) shall be included. This form is not to be
submitted to NIOSH.
(b) Roentgenograms shall be interpreted and classified only by a B-
reader, a board eligible/certified radiologist, or an experienced
physician with known expertise in pneumoconioses.
(c) All interpreters, whenever interpreting chest roentgenograms
made under this section, shall have immediately available for reference
a complete set of the ILO-U/C International Classification of
Radiographs for Pneumoconioses, 1980.
Appendix F to Sec. 1915.1001--Work Practices and Engineering Controls
for Class I Asbestos Operations Non-Mandatory
This is a non-mandatory appendix to the asbestos standards for
construction and for shipyards. It describes criteria and procedures for
erecting and using negative pressure enclosures for Class I Asbestos
Work, when NPEs are used as an allowable control method to comply with
paragraph (g)(5) (i) of this section. Many small and variable details
are involved in the erection of a negative pressure enclosure. OSHA and
most participants in the rulemaking agreed that only the major, more
performance oriented criteria should be made mandatory. These criteria
are set out in paragraph (g) of this section. In addition, this appendix
includes these mandatory specifications and procedures in its guidelines
in order to make this appendix coherent and helpful. The mandatory
nature of the criteria which appear in the regulatory text is not
changed because they are included in this ``non-mandatory'' appendix.
Similarly, the additional criteria and procedures included as guidelines
in the appendix, do not become mandatory because mandatory criteria are
also included in these comprehensive guidelines.
In addition, none of the criteria, both mandatory and recommended,
are meant to specify or imply the need for use of patented or licensed
methods or equipment. Recommended specifications included in this
attachment should not discourage the use of creative alternatives which
can be shown to reliably achieve the objectives of negative-pressure
enclosures.
Requirements included in this appendix, cover general provisions to
be followed in all asbestos jobs, provisions which must be followed for
all Class I asbestos jobs, and provisions governing the construction and
testing of negative pressure enclosures. The first category includes the
requirement for use of wet methods, HEPA vacuums, and immediate bagging
of waste; Class I work must conform to the following provisions:
oversight by competent person
use of critical barriers over all openings to
work area
isolation of HVAC systems
use of impermeable dropcloths and coverage of all
objects within regulated areas
In addition, more specific requirements for NPEs include:
maintenance of -0.02 inches water gauge within
enclosure
manometric measurements
air movement away from employees performing
removal work
smoke testing or equivalent for detection of
leaks and air direction
deactivation of electrical circuits, if not
provided with ground-fault circuit interrupters.
Planning the Project
The standard requires that an exposure assessment be conducted
before the asbestos job is begun Sec. 1915.1001(f)(1). Information
needed for that assessment, includes data relating to prior similar
jobs, as applied to the specific variables of the current job. The
information needed to conduct the assessment will be useful in planning
the project, and in complying with any reporting requirements under this
standard, when significant changes are being made to a control system
listed in the standard, [see paragraph (k) of this section], as well as
those of USEPA (40 CFR part 61, subpart M). Thus, although the standard
does not explicitly require the preparation of a written asbestos
removal plan, the usual constituents of such a plan, i.e., a description
of the enclosure, the equipment, and the procedures to be used
throughout the project, must be determined before the enclosure can be
erected. The following information should be included in the planning of
the system:
A physical description of the work area;
A description of the approximate amount of material to be removed;
A schedule for turning off and sealing existing ventilation systems;
Personnel hygiene procedures;
A description of personal protective equipment and clothing to worn
by employees;
A description of the local exhaust ventilation systems to be used
and how they are to be tested;
A description of work practices to be observed by employees;
An air monitoring plan;
A description of the method to be used to transport waste material;
and
The location of the dump site.
[[Page 177]]
Materials and Equipment Necessary for Asbestos Removal
Although individual asbestos removal projects vary in terms of the
equipment required to accomplish the removal of the materials, some
equipment and materials are common to most asbestos removal operations.
Plastic sheeting used to protect horizontal surfaces, seal HVAC
openings or to seal vertical openings and ceilings should have a minimum
thickness of 6 mils. Tape or other adhesive used to attach plastic
sheeting should be of sufficient adhesive strength to support the weight
of the material plus all stresses encountered during the entire duration
of the project without becoming detached from the surface.
Other equipment and materials which should be available at the
beginning of each project are:
--HEPA Filtered Vacuum is essential for cleaning the work area after
the asbestos has been removed. It should have a long hose capable of
reaching out-of-the-way places, such as areas above ceiling tiles,
behind pipes, etc.
--Portable air ventilation systems installed to provide the negative
air pressure and air removal from the enclosure must be equipped with a
HEPA filter. The number and capacity of units required to ventilate an
enclosure depend on the size of the area to be ventilated. The filters
for these systems should be designed in such a manner that they can be
replaced when the air flow volume is reduced by the build-up of dust in
the filtration material. Pressure monitoring devices with alarms and
strip chart recorders attached to each system to indicate the pressure
differential and the loss due to dust buildup on the filter are
recommended.
--Water sprayers should be used to keep the asbestos material as
saturated as possible during removal; the sprayers will provide a fine
mist that minimizes the impact of the spray on the material.
--Water used to saturate the asbestos containing material can be amended
by adding at least 15 milliliters (\1/4\ ounce) of wetting agent in 1
liter (1 pint) of water. An example of a wetting agent is a 50/50
mixture of polyoxyethylene ether and polyoxyethylene polyglycol ester.
--Backup power supplies are recommended, especially for ventilation
systems.
--Shower and bath water should be with mixed hot and cold water faucets.
Water that has been used to clean personnel or equipment should either
be filtered or be collected and discarded as asbestos waste. Soap and
shampoo should be provided to aid in removing dust from the workers'
skin and hair.
--See paragraphs (h) and (i) of this section for appropriate respiratory
protection and protective clothing.
--See paragraph (k) of this section for required signs and labels.
Preparing the Work Area
Disabling HVAC Systems: The power to the heating, ventilation, and
air conditioning systems that service the restricted area must be
deactivated and locked off. All ducts, grills, access ports, windows and
vents must be sealed off with two layers of plastic to prevent
entrainment of contaminated air.
Operating HVAC Systems in the Restricted Area: If components of a
HVAC system located in the restricted area are connected to a system
that will service another zone during the project, the portion of the
duct in the restricted area must be sealed and pressurized. Necessary
precautions include caulking the duct joints, covering all cracks and
openings with two layers of sheeting, and pressurizing the duct
throughout the duration of the project by restricting the return air
flow. The power to the fan supplying the positive pressure should be
locked ``on'' to prevent pressure loss.
Sealing Elevators: If an elevator shaft is located in the restricted
area, it should be either shut down or isolated by sealing with two
layers of plastic sheeting. The sheeting should provide enough slack to
accommodate the pressure changes in the shaft without breaking the air-
tight seal.
Removing Mobile Objects: All movable objects should be cleaned and
removed from the work area before an enclosure is constructed unless
moving the objects creates a hazard. Mobile objects will be assumed to
be contaminated and should be either cleaned with amended water and a
HEPA vacuum and then removed from the area or wrapped and then disposed
of as hazardous waste.
Cleaning and Sealing Surfaces: After cleaning with water and a HEPA
vacuum, surfaces of stationary objects should be covered with two layers
of plastic sheeting. The sheeting should be secured with duct tape or an
equivalent method to provide a tight seal around the object.
Bagging Waste: In addition to the requirement for immediate bagging
of waste for disposal, it is further recommended that the waste material
be double-bagged and sealed in plastic bags designed for asbestos
disposal. The bags should be stored in a waste storage area that can be
controlled by the workers conducting the removal. Filters removed from
air handling units and rubbish removed from the area are to be bagged
and handled as hazardous waste.
Constructing the Enclosure
The enclosure should be constructed to provide an air-tight seal
around ducts and
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openings into existing ventilation systems and around penetrations for
electrical conduits, telephone wires, water lines, drain pipes, etc.
Enclosures should be both airtight and watertight except for those
openings designed to provide entry and/or air flow control.
Size: An enclosure should be the minimum volume to encompass all of
the working surfaces yet allow unencumbered movement by the worker(s),
provide unrestricted air flow past the worker(s), and ensure walking
surfaces can be kept free of tripping hazards.
Shape: The enclosure may be any shape that optimizes the flow of
ventilation air past the worker(s).
Structural Integrity: The walls, ceilings and floors must be
supported in such a manner that portions of the enclosure will not fall
down during normal use.
Openings: It is not necessary that the structure be airtight;
openings may be designed to direct air flow. Such openings should be
located at a distance from active removal operations. They should be
designed to draw air into the enclosure under all anticipated
circumstances. In the event that negative pressure is lost, they should
be fitted with either HEPA filters to trap dust or automatic trap doors
that prevent dust from escaping the enclosure. Openings for exits should
be controlled by an airlock or a vestibule.
Barrier Supports: Frames should be constructed to support all
unsupported spans of sheeting.
Sheeting: Walls, barriers, ceilings, and floors should be lined with
two layers of plastic sheeting having a thickness of at least 6 mil.
Seams: Seams in the sheeting material should be minimized to reduce
the possibilities of accidental rips and tears in the adhesive or
connections. All seams in the sheeting should overlap, be staggered and
not be located at corners or wall-to- floor joints. Areas Within an
Enclosure: Each enclosure consists of a work area, a decontamination
area, and waste storage area. The work area where the asbestos removal
operations occur should be separated from both the waste storage area
and the contamination control area by physical curtains, doors, and/or
airflow patterns that force any airborne contamination back into the
work area.
See paragraph (j) of Sec. 1915.1001 for requirements for hygiene
facilities.
During egress from the work area, each worker should step into the
equipment room, clean tools and equipment, and remove gross
contamination from clothing by wet cleaning and HEPA vacuuming. Before
entering the shower area, foot coverings, head coverings, hand
coverings, and coveralls are removed and placed in impervious bags for
disposal or cleaning. Airline connections from airline respirators with
HEPA disconnects and power cables from powered air-purifying respirators
(PAPRs) will be disconnected just prior to entering the shower room.
Establishing Negative Pressure Within the Enclosure
Negative Pressure: Air is to be drawn into the enclosure under all
anticipated conditions and exhausted through a HEPA filter for 24 hours
a day during the entire duration of the project.
Air Flow Tests: Air flow patterns will be checked before removal
operations begin, at least once per operating shift and any time there
is a question regarding the integrity of the enclosure. The primary test
for air flow is to trace air currents with smoke tubes or other visual
methods. Flow checks are made at each opening and at each doorway to
demonstrate that air is being drawn into the enclosure and at each
worker's position to show that air is being drawn away from the
breathing zone.
Monitoring Pressure Within the Enclosure: After the initial air flow
patterns have been checked, the static pressure must be monitored within
the enclosure. Monitoring may be made using manometers, pressure gauges,
or combinations of these devices. It is recommended that they be
attached to alarms and strip chart recorders at points identified by the
design engineer.
Corrective Actions: If the manometers or pressure gauges demonstrate
a reduction in pressure differential below the required level, work
should cease and the reason for the change investigated and appropriate
changes made. The air flow patterns should be retested before work
begins again.
Pressure Differential: The design parameters for static pressure
differentials between the inside and outside of enclosures typically
range from 0.02 to 0.10 inches of water gauge, depending on conditions.
All zones inside the enclosure must have less pressure than the ambient
pressure outside of the enclosure (-0.02 inches water gauge
differential). Design specifications for the differential vary according
to the size, configuration, and shape of the enclosure as well as
ambient and mechanical air pressure conditions around the enclosure.
Air Flow Patterns: The flow of air past each worker shall be
enhanced by positioning the intakes and exhaust ports to remove
contaminated air from the worker's breathing zone, by positioning HEPA
vacuum cleaners to draw air from the worker's breathing zone, by forcing
relatively uncontaminated air past the worker toward an exhaust port, or
by using a combination of methods to reduce the worker's exposure.
Air Handling Unit Exhaust: The exhaust plume from air handling units
should be located away from adjacent personnel and intakes for HVAC
systems.
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Air Flow Volume: The air flow volume (cubic meters per minute)
exhausted (removed) from the workplace must exceed the amount of makeup
air supplied to the enclosure. The rate of air exhausted from the
enclosure should be designed to maintain a negative pressure in the
enclosure and air movement past each worker. The volume of air flow
removed from the enclosure should replace the volume of the container at
every 5 to 15 minutes. Air flow volume will need to be relatively high
for large enclosures, enclosures with awkward shapes, enclosures with
multiple openings, and operations employing several workers in the
enclosure.
Air Flow Velocity: At each opening, the air flow velocity must
visibly ``drag'' air into the enclosure. The velocity of air flow within
the enclosure must be adequate to remove airborne contamination from
each worker's breathing zone without disturbing the asbestos-containing
material on surfaces.
Airlocks: Airlocks are mechanisms on doors and curtains that control
the air flow patterns in the doorways. If air flow occurs, the patterns
through doorways must be such that the air flows toward the inside of
the enclosure. Sometimes vestibules, double doors, or double curtains
are used to prevent air movement through the doorways. To use a
vestibule, a worker enters a chamber by opening the door or curtain and
then closing the entry before opening the exit door or curtain.
Airlocks should be located between the equipment room and shower
room, between the shower room and the clean room, and between the waste
storage area and the outside of the enclosure. The air flow between
adjacent rooms must be checked using smoke tubes or other visual tests
to ensure the flow patterns draw air toward the work area without
producing eddies.
Monitoring for Airborne Concentrations
In addition to the breathing zone samples taken as outlined in
paragraph (f) of Sec. 1915.1001 , samples of air should be taken to
demonstrate the integrity of the enclosure, the cleanliness of the clean
room and shower area, and the effectiveness of the HEPA filter. If the
clean room is shown to be contaminated, the room must be relocated to an
uncontaminated area.
Samples taken near the exhaust of portable ventilation systems must
be done with care.
General Work Practices
Preventing dust dispersion is the primary means of controlling the
spread of asbestos within the enclosure. Whenever practical, the point
of removal should be isolated, enclosed, covered, or shielded from the
workers in the area. Waste asbestos containing materials must be bagged
during or immediately after removal; the material must remain saturated
until the waste container is sealed.
Waste material with sharp points or corners must be placed in hard
air-tight containers rather than bags.
Whenever possible, large components should be sealed in plastic
sheeting and removed intact.
Bags or containers of waste will be moved to the waste holding area,
washed, and wrapped in a bag with the appropriate labels.
Cleaning the Work Area
Surfaces within the work area should be kept free of visible dust
and debris to the extent feasible. Whenever visible dust appears on
surfaces, the surfaces within the enclosure must be cleaned by wiping
with a wet sponge, brush, or cloth and then vacuumed with a HEPA vacuum.
All surfaces within the enclosure should be cleaned before the
exhaust ventilation system is deactivated and the enclosure is
disassembled. An approved encapsulant may be sprayed onto areas after
the visible dust has been removed.
Appendix G to Sec. 1915.1001 [Reserved]
Appendix H to Sec. 1915.1001--Substance Technical Information for
Asbestos. Non-Mandatory
I. Substance Identification
A. Substance: ``Asbestos'' is the name of a class of magnesium-
silicate minerals that occur in fibrous form. Minerals that are included
in this group are chrysotile, crocidolite, amosite, anthophyllite
asbestos, tremolite asbestos, and actinolite asbestos.
B. Asbestos is and was used in the manufacture of heat-resistant
clothing, automotive brake and clutch linings, and a variety of building
materials including floor tiles, roofing felts, ceiling tiles, asbestos-
cement pipe and sheet, and fire-resistant drywall. Asbestos is also
present in pipe and boiler insulation materials and in sprayed-on
materials located on beams, in crawlspaces, and between walls.
C. The potential for an asbestos-containing product to release
breathable fibers depends largely on its degree of friability. Friable
means that the material can be crumbled with hand pressure and is
therefore likely to emit fibers. The fibrous fluffy sprayed-on materials
used for fireproofing, insulation, or sound proofing are considered to
be friable, and they readily release airborne fibers if disturbed.
Materials such as vinyl-asbestos floor tile or roofing felt are
considered non-friable if intact and generally do not emit airborne
fibers unless subjected to sanding, sawing and other aggressive
operations. Asbestos--cement pipe or sheet can emit airborne fibers if
the materials are cut or sawed, or if they are broken.
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D. Permissible exposure: Exposure to airborne asbestos fibers may
not exceed 0.1 fibers per cubic centimeter of air (0.1 f/cc) averaged
over the 8-hour workday, and 1 fiber per cubic centimeter of air (1.0 f/
cc) averaged over a 30 minute work period.
II. Health Hazard Data
A. Asbestos can cause disabling respiratory disease and various
types of cancers if the fibers are inhaled. Inhaling or ingesting fibers
from contaminated clothing or skin can also result in these diseases.
The symptoms of these diseases generally do not appear for 20 or more
years after initial exposure.
B. Exposure to asbestos has been shown to cause lung cancer,
mesothelioma, and cancer of the stomach and colon. Mesothelioma is a
rare cancer of the thin membrane lining of the chest and abdomen.
Symptoms of mesothelioma include shortness of breath, pain in the walls
of the chest, and/or abdominal pain.
III. Respirators and Protective Clothing
A. Respirators: You are required to wear a respirator when
performing tasks that result in asbestos exposure that exceeds the
permissible exposure limit (PEL) of 0.1 f/cc and when performing certain
designated operations. Air-purifying respirators equipped with a high-
efficiency particulate air (HEPA) filter can be used where airborne
asbestos fiber concentrations do not exceed 1.0 f/cc; otherwise, more
protective respirators such as air-supplied, positive-pressure, full
facepiece respirators must be used. Disposable respirators or dust masks
are not permitted to be used for asbestos work. For effective
protection, respirators must fit your face and head snugly. Your
employer is required to conduct a fit test when you are first assigned a
respirator and every 6 months thereafter. Respirators should not be
loosened or removed in work situations where their use is required.
B. Protective Clothing: You are required to wear protective clothing
in work areas where asbestos fiber concentrations exceed the permissible
exposure limit (PEL) of 0.1 f/cc.
IV. Disposal Procedures and Clean-up
A. Wastes that are generated by processes where asbestos is present
include:
1. Empty asbestos shipping containers.
2. Process wastes such as cuttings, trimmings, or reject materials.
3. Housekeeping waste from wet-sweeping or HEPA-vacuuming.
4. Asbestos fireproofing or insulating material that is removed from
buildings.
5. Asbestos-containing building products removed during building
renovation or demolition.
6. Contaminated disposable protective clothing.
B. Empty shipping bags can be flattened under exhaust hoods and
packed into airtight containers for disposal. Empty shipping drums are
difficult to clean and should be sealed.
C. Vacuum bags or disposable paper filters should not be cleaned,
but should be sprayed with a fine water mist and placed into a labeled
waste container.
D. Process waste and housekeeping waste should be wetted with water
or a mixture of water and surfactant prior to packaging in disposable
containers.
E. Asbestos-containing material that is removed from buildings must
be disposed of in leak-tight 6-mil plastic bags, plastic-lined cardboard
containers, or plastic-lined metal containers. These wastes, which are
removed while wet, should be sealed in containers before they dry out to
minimize the release of asbestos fibers during handling.
V. Access to Information
A. Each year, your employer is required to inform you of the
information contained in this standard and appendices for asbestos. In
addition, your employer must instruct you in the proper work practices
for handling asbestos-containing materials, and the correct use of
protective equipment.
B. Your employer is required to determine whether you are being
exposed to asbestos. Your employer must treat exposure to thermal system
insulation and sprayed-on and troweled-on surfacing material as asbestos
exposure, unless results of laboratory analysis show that the material
does not contain asbestos. You or your representative has the right to
observe employee measurements and to record the results obtained. Your
employer is required to inform you of your exposure, and, if you are
exposed above the permissible exposure limit, he or she is required to
inform you of the actions that are being taken to reduce your exposure
to within the permissible limit.
C. Your employer is required to keep records of your exposures and
medical examinations. These exposure records must be kept for at least
thirty (30) years. Medical records must be kept for the period of your
employment plus thirty (30) years.
D. Your employer is required to release your exposure and medical
records to your physician or designated representative upon your written
request.
Appendix I to Sec. 1915.1001--Medical Surveillance Guidelines for
Asbestos, Non-Mandatory
I. Route of Entry
Inhalation, ingestion.
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II. Toxicology
Clinical evidence of the adverse effects associated with exposure to
asbestos is present in the form of several well- conducted
epidemiological studies of occupationally exposed workers, family
contacts of workers, and persons living near asbestos mines. These
studies have shown a definite association between exposure to asbestos
and an increased incidence of lung cancer, pleural and peritoneal
mesothelioma, gastrointestinal cancer, and asbestosis. The latter is a
disabling fibrotic lung disease that is caused only by exposure to
asbestos. Exposure to asbestos has also been associated with an
increased incidence of esophageal, kidney, laryngeal, pharyngeal, and
buccal cavity cancers. As with other known chronic occupational
diseases, disease associated with asbestos generally appears about 20
years following the first occurrence of exposure: There are no known
acute effects associated with exposure to asbestos.
Epidemiological studies indicate that the risk of lung cancer among
exposed workers who smoke cigarettes is greatly increased over the risk
of lung cancer among non-exposed smokers or exposed nonsmokers. These
studies suggest that cessation of smoking will reduce the risk of lung
cancer for a person exposed to asbestos but will not reduce it to the
same level of risk as that existing for an exposed worker who has never
smoked.
III. Signs and Symptoms of Exposure Related Disease
The signs and symptoms of lung cancer or gastrointestinal cancer
induced by exposure to asbestos are not unique, except that a chest X-
ray of an exposed patient with lung cancer may show pleural plaques,
pleural calcification, or pleural fibrosis. Symptoms characteristic of
mesothelioma include shortness of breath, pain in the walls of the
chest, or abdominal pain. Mesothelioma has a much longer latency period
compared with lung cancer (40 years versus 15-20 years), and
mesothelioma is therefore more likely to be found among workers who were
first exposed to asbestos at an early age. Mesothelioma is always fatal.
Asbestosis is pulmonary fibrosis caused by the accumulation of
asbestos fibers in the lungs. Symptoms include shortness of breath,
coughing, fatigue, and vague feelings of sickness. When the fibrosis
worsens, shortness of breath occurs even at rest. The diagnosis of
asbestosis is based on a history of exposure to asbestos, the presence
of characteristics radiologic changes, end-inspiratory crackles (rales),
and other clinical features of fibrosing lung disease. Pleural plaques
and thickening are observed on X-rays taken during the early sates of
the disease. Asbestosis is often a progressive disease even in the
absence of continued exposure, although this appears to be a highly
individualized characteristic. In severe cases, death may be caused by
respiratory or cardiac failure.
IV. Surveillance and Preventive Considerations
As noted above, exposure to asbestos have been linked to an
increased risk of lung cancer, mesothelioma, gastrointestinal cancer,
and asbestosis among occupationally exposed workers. Adequate screening
tests to determine an employee's potential for developing serious
chronic diseases, such as a cancer, from exposure to asbestos do not
presently exist. However, some tests, particularly chest X-rays and
pulmonary function tests, may indicate that an employee has been
overexposed to asbestos increasing his or her risk of developing
exposure related chronic diseases. It is important for the physician to
become familiar with the operating conditions in which occupational
exposure to asbestos is likely to occur. This is particularly important
in evaluating medical and work histories and in conducting physical
examinations. When an active employee has been identified as having been
overexposed to asbestos measures taken by the employer to eliminate or
mitigate further exposure should also lower the risk of serious long-
term consequences.
The employer is required to institute a medical surveillance program
for all employees who are or will be exposed to asbestos at or above the
permissible exposure limits (0.1 fiber per cubic centimeter of air) for
30 or more days per year and for all employees who are assigned to wear
a negative-pressure respirator. All examinations and procedures must be
performed by or under the supervision of licensed physician at a
reasonable time and place, and at no cost to the employee.
Although broad latitude is given to the physician in prescribing
specific tests to be included in the medical surveillance program, OSHA
requires inclusion of the following elements in the routine examination,
(i) Medical and work histories with special emphasis directed to
symptoms of the respiratory system, cardiovascular system, and digestive
tract.
(ii) Completion of the respiratory disease questionnaire contained
in appendix D to this section.
(iii) A physical examination including a chest roentgenogram and
pulmonary function test that include measurement of the employee's
forced vital capacity (FYC) and forced expiratory volume at one second
(FEV1).
(iv) Any laboratory or other test that the examining physician deems
by sound medical practice to be necessary.
The employer is required to make the prescribed tests available at
least annually to those employees covered; more often than specified if
recommended by the examining
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physician; and upon termination of employment.
The employer is required to provide the physician with the following
information: A copy of this standard and appendices; a description of
the employee's duties as they relate to asbestos exposure; the
employee's representative level of exposure to asbestos; a description
of any personal protective and respiratory equipment used; and
information from previous medical examinations of the affected employee
that is not otherwise available to the physician. Making this
information available to the physician will aid in the evaluation of the
employee's health in relation to assigned duties and fitness to wear
personal protective equipment, if required.
The employer is required to obtain a written opinion from the
examining physician containing the results of the medical examination;
the physician's opinion as to whether the employee has any detected
medical conditions that would place the employee at an increased risk of
exposure-related disease; any recommended limitations on the employee or
on the use of personal protective equipment; and a statement that the
employee has been informed by the physician of the results of the
medical examination and of any medical conditions related to asbestos
exposure that require further explanation or treatment. This written
opinion must not reveal specific findings or diagnoses unrelated to
exposure to asbestos, and a copy of the opinion must be provided to the
affected employee.
Appendix J to Sec. 1915.1001--Smoking Cessation Program Information for
Asbestos--Non-Mandatory
The following organizations provide smoking cessation information.
1. The National Cancer Institute operates a toll-free Cancer
Information Service (CIS) with trained personnel to help you. Call 1-
800-4-CANCER* to reach the CIS office serving your area, or write:
Office of Cancer Communications, National Cancer Institute, National
Institutes of Health, Building 31, Room 10A24, Bethesda, Maryland 20892.
2. American Cancer Society, 3340 Peachtree Road, N.E., Atlanta,
Georgia 30026, (404) 320-3333.
The American Cancer Society (ACS) is a voluntary organization
composed of 58 divisions and 3,100 local units. Through ``The Great
American Smokeout'' in November, the annual Cancer Crusade in April, and
numerous educational materials, ACS helps people learn about the health
hazards of smoking and become successful ex-smokers.
3. American Heart Association, 7320 Greenville Avenue, Dallas, Texas
75231, (214) 750-5300.
The American Heart Association (AHA) is a voluntary organization
with 130,000 members (physicians, scientists, and laypersons) in 55
state and regional groups. AHA produces a variety of publications and
audiovisual materials about the effects of smoking on the heart. AHA
also has developed a guidebook for incorporating a weight-control
component into smoking cessation programs.
4. American Lung Association, 1740 Broadway, New York, New York
10019, (212) 245-8000.
A voluntary organization of 7,500 members (physicians, nurses, and
laypersons), the American Lung Association (ALA) conducted numerous
public information programs about the health effects of smoking. ALA has
59 state and 85 local units. The organization actively supports
legislation and information campaigns for non-smokers' rights and
provides help for smokers who want to quit, for example, through
``Freedom From Smoking,'' a self-help smoking cessation program.
5. Office on Smoking and Health, U.S. Department of Health and Human
Services 5600 Fishers Lane, Park Building, Room 110, Rockville, Maryland
20857.
The Office on Smoking and Health (OSHA) is the Department of Health
and Human Services' lead agency in smoking control. OSHA has sponsored
distribution of publications on smoking-related topics, such as free
flyers on relapse after initial quitting, helping a friend or family
member quit smoking, the health hazards of smoking, and the effects of
parental smoking on teenagers.
*In Hawaii, on Oahu call 524-1234 (call collect from neighboring
islands),
Spanish-speaking staff members are available during daytime hours to
callers from the following areas: California, Florida, Georgia,
Illinois, New Jersey (area code 201), New York, and Texas. Consult your
local telephone directory for listings of local chapters.
Appendix K to Sec. 1915.1001--Polarized Light Microscopy of Asbestos--
Non-Mandatory
Method number: ID-191
Matrix: Bulk
Collection Procedure
Collect approximately 1 to 2 grams of each type of material and
place into separate 20 mL scintillation vials.
Analytical Procedure
A portion of each separate phase is analyzed by gross examination,
phase-polar examination, and central stop dispersion microscopy.
Commercial manufacturers and products mentioned in this method are
for descriptive use only and do not constitute endorsements by USDOL-
OSHA. Similar products from other sources may be substituted.
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1. Introduction
This method describes the collection and analysis of asbestos bulk
materials by light microscopy techniques including phase- polar
illumination and central-stop dispersion microscopy. Some terms unique
to asbestos analysis are defined below:
Amphibole: A family of minerals whose crystals are formed by long,
thin units which have two thin ribbons of double chain silicate with a
brucite ribbon in between. The shape of each unit is similar to an ``I
beam''. Minerals important in asbestos analysis include cummingtonite-
grunerite, crocidolite, tremolite- actinolite and anthophyllite.
Asbestos: A term for naturally occurring fibrous minerals. Asbestos
includes chrysotile, cummingtonite-grunerite asbestos (amosite),
anthophyllite asbestos, tremolite asbestos, crocidolite, actinolite
asbestos and any of these minerals which have been chemically treated or
altered. The precise chemical formulation of each species varies with
the location from which it was mined. Nominal compositions are listed:
Chrysotile...............................Mg3 Si2
O5(OH)4
Crocidolite (Riebeckite asbestos)
Na2Fe32+Fe23+Si8O22
(OH)2
Cummingtonite-Grunerite asbestos (Amosite)...............
...(Mg,Fe)7
Si8O22(OH)2
Tremolite-Actinolite asbestos
Ca2(Mg,Fe)5Si8O22(OH)2
Anthophyllite asbestos..............(Mg,Fe)7
Si8O22(OH)2
Asbestos Fiber: A fiber of asbestos meeting the criteria for a
fiber. (See section 3.5.)
Aspect Ratio: The ratio of the length of a fiber to its diameter
usually defined as ``length : width'', e.g. 3:1.
Brucite: A sheet mineral with the composition Mg(OH)2.
Central Stop Dispersion Staining (microscope): This is a dark field
microscope technique that images particles using only light refracted by
the particle, excluding light that travels through the particle
unrefracted. This is usually accomplished with a McCrone objective or
other arrangement which places a circular stop with apparent aperture
equal to the objective aperture in the back focal plane of the
microscope.
Cleavage Fragments: Mineral particles formed by the comminution of
minerals, especially those characterized by relatively parallel sides
and moderate aspect ratio.
Differential Counting: The term applied to the practice of excluding
certain kinds of fibers from a phase contrast asbestos count because
they are not asbestos.
Fiber: A particle longer than or equal to 5 [micro]m with a length
to width ratio greater than or equal to 3:1. This may include cleavage
fragments. (see section 3.5 of this appendix).
Phase Contrast: Contrast obtained in the microscope by causing light
scattered by small particles to destructively interfere with unscattered
light, thereby enhancing the visibility of very small particles and
particles with very low intrinsic contrast.
Phase Contrast Microscope: A microscope configured with a phase mask
pair to create phase contrast. The technique which uses this is called
Phase Contrast Microscopy (PCM).
Phase-Polar Analysis: This is the use of polarized light in a phase
contrast microscope. It is used to see the same size fibers that are
visible in air filter analysis. Although fibers finer than 1 [micro]m
are visible, analysis of these is inferred from analysis of larger
bundles that are usually present.
Phase-Polar Microscope: The phase-polar microscope is a phase
contrast microscope which has an analyzer, a polarizer, a first order
red plate and a rotating phase condenser all in place so that the
polarized light image is enhanced by phase contrast.
Sealing Encapsulant: This is a product which can be applied,
preferably by spraying, onto an asbestos surface which will seal the
surface so that fibers cannot be released.
Serpentine: A mineral family consisting of minerals with the general
composition Mg3(Si2O5(OH)4 having the
magnesium in brucite layer over a silicate layer. Minerals important in
asbestos analysis included in this family are chrysotile, lizardite,
antigorite.
1.1. History
Light microscopy has been used for well over 100 years for the
determination of mineral species. This analysis is carried out using
specialized polarizing microscopes as well as bright field microscopes.
The identification of minerals is an on-going process with many new
minerals described each year. The first recorded use of asbestos was in
Finland about 2500 B.C. where the material was used in the mud wattle
for the wooden huts the people lived in as well as strengthening for
pottery. Adverse health aspects of the mineral were noted nearly 2000
years ago when Pliny the Younger wrote about the poor health of slaves
in the asbestos mines. Although known to be injurious for centuries, the
first modern references to its toxicity were by the British Labor
Inspectorate when it banned asbestos dust from the workplace in 1898.
Asbestosis cases were described in the literature after the turn of the
century. Cancer was first suspected in the mid 1930's and a causal link
to mesothelioma was made in 1965. Because of the public concern for
worker and public safety with the use of this material, several
different types of analysis were applied to the determination of
asbestos content. Light microscopy requires a great deal of experience
and craft. Attempts were made to apply less subjective methods to the
analysis. X-ray diffraction was partially successful in determining the
mineral types but was unable to separate out the fibrous portions
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from the non-fibrous portions. Also, the minimum detection limit for
asbestos analysis by X-ray diffraction (XRD) is about 1%. Differential
Thermal Analysis (DTA) was no more successful. These provide useful
corroborating information when the presence of asbestos has been shown
by microscopy; however, neither can determine the difference between
fibrous and non-fibrous minerals when both habits are present. The same
is true of Infrared Absorption (IR).
When electron microscopy was applied to asbestos analysis, hundreds
of fibers were discovered present too small to be visible in any light
microscope. There are two different types of electron microscope used
for asbestos analysis: Scanning Electron Microscope (SEM) and
Transmission Electron Microscope (TEM). Scanning Electron Microscopy is
useful in identifying minerals. The SEM can provide two of the three
pieces of information required to identify fibers by electron
microscopy: morphology and chemistry. The third is structure as
determined by Selected Area Electron Diffraction--SAED which is
performed in the TEM. Although the resolution of the SEM is sufficient
for very fine fibers to be seen, accuracy of chemical analysis that can
be performed on the fibers varies with fiber diameter in fibers of less
than 0.2 [micro]m diameter. The TEM is a powerful tool to identify
fibers too small to be resolved by light microscopy and should be used
in conjunction with this method when necessary. The TEM can provide all
three pieces of information required for fiber identification. Most
fibers thicker than 1 [micro]m can adequately be defined in the light
microscope. The light microscope remains as the best instrument for the
determination of mineral type. This is because the minerals under
investigation were first described analytically with the light
microscope. It is inexpensive and gives positive identification for most
samples analyzed. Further, when optical techniques are inadequate, there
is ample indication that alternative techniques should be used for
complete identification of the sample.
1.2. Principle
Minerals consist of atoms that may be arranged in random order or in
a regular arrangement. Amorphous materials have atoms in random order
while crystalline materials have long range order. Many materials are
transparent to light, at least for small particles or for thin sections.
The properties of these materials can be investigated by the effect that
the material has on light passing through it. The six asbestos minerals
are all crystalline with particular properties that have been identified
and cataloged. These six minerals are anisotropic. They have a regular
array of atoms, but the arrangement is not the same in all directions.
Each major direction of the crystal presents a different regularity.
Light photons travelling in each of these main directions will encounter
different electrical neighborhoods, affecting the path and time of
travel. The techniques outlined in this method use the fact that light
traveling through fibers or crystals in different directions will behave
differently, but predictably. The behavior of the light as it travels
through a crystal can be measured and compared with known or determined
values to identify the mineral species. Usually, Polarized Light
Microscopy (PLM) is performed with strain-free objectives on a bright-
field microscope platform. This would limit the resolution of the
microscope to about 0.4 [micro]m. Because OSHA requires the counting and
identification of fibers visible in phase contrast, the phase contrast
platform is used to visualize the fibers with the polarizing elements
added into the light path. Polarized light methods cannot identify
fibers finer than about 1[micro]m in diameter even though they are
visible. The finest fibers are usually identified by inference from the
presence of larger, identifiable fiber bundles. When fibers are present,
but not identifiable by light microscopy, use either SEM or TEM to
determine the fiber identity.
1.3. Advantages and Disadvantages
The advantages of light microcopy are:
(a) Basic identification of the materials was first performed by
light microscopy and gross analysis. This provides a large base of
published information against which to check analysis and analytical
technique.
(b) The analysis is specific to fibers. The minerals present can
exist in asbestiform, fibrous, prismatic, or massive varieties all at
the same time. Therefore, bulk methods of analysis such as X-ray
diffraction, IR analysis, DTA, etc. are inappropriate where the material
is not known to be fibrous.
(c) The analysis is quick, requires little preparation time, and can
be performed on-site if a suitably equipped microscope is available.
The disadvantages are:
(a) Even using phase-polar illumination, not all the fibers present
may be seen. This is a problem for very low asbestos concentrations
where agglomerations or large bundles of fibers may not be present to
allow identification by inference.
(b) The method requires a great degree of sophistication on the part
of the microscopist. An analyst is only as useful as his mental catalog
of images. Therefore, a microscopist's accuracy is enhanced by
experience. The mineralogical training of the analyst is very important.
It is the basis on which subjective decisions are made.
(c) The method uses only a tiny amount of material for analysis.
This may lead to sampling bias and false results (high or low).
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This is especially true if the sample is severely inhomogeneous.
(d) Fibers may be bound in a matrix and not distinguishable as
fibers so identification cannot be made.
1.4. Method Performance
1.4.1. This method can be used for determination of asbestos content
from 0 to 100% asbestos. The detection limit has not been adequately
determined, although for selected samples, the limit is very low,
depending on the number of particles examined. For mostly homogeneous,
finely divided samples, with no difficult fibrous interferences, the
detection limit is below 1%. For inhomogeneous samples (most samples),
the detection limit remains undefined. NIST has conducted proficiency
testing of laboratories on a national scale. Although each round is
reported statistically with an average, control limits, etc., the
results indicate a difficulty in establishing precision especially in
the low concentration range. It is suspected that there is significant
bias in the low range especially near 1%. EPA tried to remedy this by
requiring a mandatory point counting scheme for samples less than 10%.
The point counting procedure is tedious, and may introduce significant
biases of its own. It has not been incorporated into this method.
1.4.2. The precision and accuracy of the quantitation tests
performed in this method are unknown. Concentrations are easier to
determine in commercial products where asbestos was deliberately added
because the amount is usually more than a few percent. An analyst's
results can be ``calibrated'' against the known amounts added by the
manufacturer. For geological samples, the degree of homogeneity affects
the precision.
1.4.3. The performance of the method is analyst dependent. The
analyst must choose carefully and not necessarily randomly the portions
for analysis to assure that detection of asbestos occurs when it is
present. For this reason, the analyst must have adequate training in
sample preparation, and experience in the location and identification of
asbestos in samples. This is usually accomplished through substantial
on-the-job training as well as formal education in mineralogy and
microscopy.
1.5. Interferences
Any material which is long, thin, and small enough to be viewed
under the microscope can be considered an interference for asbestos.
There are literally hundreds of interferences in workplaces. The
techniques described in this method are normally sufficient to eliminate
the interferences. An analyst's success in eliminating the interferences
depends on proper training.
Asbestos minerals belong to two mineral families: the serpentines
and the amphiboles. In the serpentine family, the only common fibrous
mineral is chrysotile. Occasionally, the mineral antigorite occurs in a
fibril habit with morphology similar to the amphiboles. The amphibole
minerals consist of a score of different minerals of which only five are
regulated by federal standard: amosite, crocidolite, anthophyllite
asbestos, tremolite asbestos and actinolite asbestos. These are the only
amphibole minerals that have been commercially exploited for their
fibrous properties; however, the rest can and do occur occasionally in
asbestiform habit.
In addition to the related mineral interferences, other minerals
common in building material may present a problem for some
microscopists: gypsum, anhydrite, brucite, quartz fibers, talc fibers or
ribbons, wollastonite, perlite, attapulgite, etc. Other fibrous
materials commonly present in workplaces are: fiberglass, mineral wool,
ceramic wool, refractory ceramic fibers, kevlar, nomex, synthetic
fibers, graphite or carbon fibers, cellulose (paper or wood) fibers,
metal fibers, etc.
Matrix embedding material can sometimes be a negative interference.
The analyst may not be able to easily extract the fibers from the matrix
in order to use the method. Where possible, remove the matrix before the
analysis, taking careful note of the loss of weight. Some common matrix
materials are: vinyl, rubber, tar, paint, plant fiber, cement, and
epoxy. A further negative interference is that the asbestos fibers
themselves may be either too small to be seen in Phase contrast
Microscopy (PCM) or of a very low fibrous quality, having the appearance
of plant fibers. The analyst's ability to deal with these materials
increases with experience.
1.6. Uses and Occupational Exposure
Asbestos is ubiquitous in the environment. More than 40% of the land
area of the United States is composed of minerals which may contain
asbestos. Fortunately, the actual formation of great amounts of asbestos
is relatively rare. Nonetheless, there are locations in which
environmental exposure can be severe such as in the Serpentine Hills of
California.
There are thousands of uses for asbestos in industry and the home.
Asbestos abatement workers are the most current segment of the
population to have occupational exposure to great amounts of asbestos.
If the material is undisturbed, there is no exposure. Exposure occurs
when the asbestos-containing material is abraded or otherwise disturbed
during maintenance operations or some other activity. Approximately 95%
of the asbestos in place in the United States is chrysotile.
Amosite and crocidolite make up nearly all the difference. Tremolite
and anthophyllite make up a very small percentage. Tremolite is found in
extremely small
[[Page 186]]
amounts in certain chrysotile deposits. Actinolite exposure is probably
greatest from environmental sources, but has been identified in
vermiculite containing, sprayed-on insulating materials which may have
been certified as asbestos-free.
1.7. Physical and Chemical Properties
The nominal chemical compositions for the asbestos minerals were
given in Section 1. Compared to cleavage fragments of the same minerals,
asbestiform fibers possess a high tensile strength along the fiber axis.
They are chemically inert, non-combustible, and heat resistant. Except
for chrysotile, they are insoluble in Hydrochloric acid (HCl).
Chrysotile is slightly soluble in HCl. Asbestos has high electrical
resistance and good sound absorbing characteristics. It can be woven
into cables, fabrics or other textiles, or matted into papers, felts,
and mats.
1.8. Toxicology (This Section is for Information Only and Should Not Be
Taken as OSHA Policy)
Possible physiologic results of respiratory exposure to asbestos are
mesothelioma of the pleura or peritoneum, interstitial fibrosis,
asbestosis, pneumoconiosis, or respiratory cancer. The possible
consequences of asbestos exposure are detailed in the NIOSH Criteria
Document or in the OSHA Asbestos Standards 29 CFR 1910.1001 and 29 CFR
1926.1101 and 29 CFR 1915.1001.
2. Sampling Procedure
2.1. Equipment for Sampling
(a) Tube or cork borer sampling device
(b) Knife
(c) 20 mL scintillation vial or similar vial
(d) Sealing encapsulant
2.2. Safety Precautions
Asbestos is a known carcinogen. Take care when sampling. While in an
asbestos-containing atmosphere, a properly selected and fit-tested
respirator should be worn. Take samples in a manner to cause the least
amount of dust. Follow these general guidelines:
(a) Do not make unnecessary dust.
(b) Take only a small amount (1 to 2 g).
(c) Tightly close the sample container.
(d) Use encapsulant to seal the spot where the sample was taken, if
necessary.
2.3. Sampling procedure
Samples of any suspect material should be taken from an
inconspicuous place. Where the material is to remain, seal the sampling
wound with an encapsulant to eliminate the potential for exposure from
the sample site. Microscopy requires only a few milligrams of material.
The amount that will fill a 20 mL scintillation vial is more than
adequate. Be sure to collect samples from all layers and phases of
material. If possible, make separate samples of each different phase of
the material. This will aid in determining the actual hazard. DO NOT USE
ENVELOPES, PLASTIC OR PAPER BAGS OF ANY KIND TO COLLECT SAMPLES. The use
of plastic bags presents a contamination hazard to laboratory personnel
and to other samples. When these containers are opened, a bellows effect
blows fibers out of the container onto everything, including the person
opening the container.
If a cork-borer type sampler is available, push the tube through the
material all the way, so that all layers of material are sampled. Some
samplers are intended to be disposable. These should be capped and sent
to the laboratory. If a non-disposable cork borer is used, empty the
contents into a scintillation vial and send to the laboratory.
Vigorously and completely clean the cork borer between samples.
2.4 Shipment
Samples packed in glass vials must not touch or they might break in
shipment.
(a) Seal the samples with a sample seal over the end to guard
against tampering and to identify the sample.
(b) Package the bulk samples in separate packages from the air
samples. They may cross-contaminate each other and will invalidate the
results of the air samples.
(c) Include identifying paperwork with the samples, but not in
contact with the suspected asbestos.
(d) To maintain sample accountability, ship the samples by certified
mail, overnight express, or hand carry them to the laboratory.
3. Analysis
The analysis of asbestos samples can be divided into two major
parts: sample preparation and microscopy. Because of the different
asbestos uses that may be encountered by the analyst, each sample may
need different preparation steps. The choices are outlined below. There
are several different tests that are performed to identify the asbestos
species and determine the percentage. They will be explained below.
3.1. Safety
(a) Do not create unnecessary dust. Handle the samples in HEPA-
filter equipped hoods. If samples are received in bags, envelopes or
other inappropriate container, open them only in a hood having a face
velocity at or greater than 100 fpm. Transfer a small amount to a
scintillation vial and only handle the smaller amount.
(b) Open samples in a hood, never in the open lab area.
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(c) Index of refraction oils can be toxic. Take care not to get this
material on the skin. Wash immediately with soap and water if this
happens.
(d) Samples that have been heated in the muffle furnace or the
drying oven may be hot. Handle them with tongs until they are cool
enough to handle.
(e) Some of the solvents used, such as THF (tetrahydrofuran), are
toxic and should only be handled in an appropriate fume hood and
according to instructions given in the Material Safety Data Sheet
(MSDS).
3.2. Equipment
(a) Phase contrast microscope with 10x, 16x and 40x objectives, 10x
wide-field eyepieces, G-22 Walton-Beckett graticule, Whipple disk,
polarizer, analyzer and first order red or gypsum plate, 100 Watt
illuminator, rotating position condenser with oversize phase rings,
central stop dispersion objective, Kohler illumination and a rotating
mechanicalstage. (See figure 1).
(b) Stereo microscope with reflected light illumination, transmitted
light illumination, polarizer, analyzer and first order red or gypsum
plate, and rotating stage.
(c) Negative pressure hood for the stereo microscope
(d) Muffle furnace capable of 600 [deg]C
(e) Drying oven capable of 50-150 [deg]C
(f) Aluminum specimen pans
(g) Tongs for handling samples in the furnace
(h) High dispersion index of refraction oils (Special for dispersion
staining.)
n = 1.550
n = 1.585
n = 1.590
n = 1.605
n = 1.620
n = 1.670
n = 1.680
n = 1.690
(i) A set of index of refraction oils from about n=1.350 to n=2.000
in n=0.005 increments. (Standard for Becke line analysis.)
(j) Glass slides with painted or frosted ends 1x3 inches 1mm thick,
precleaned.
(k) Cover Slips 22x22 mm, 1\1/2\
(l) Paper clips or dissection needles
(m) Hand grinder
(n) Scalpel with both 10 and 11 blades
(o) 0.1 molar HCl
(p) Decalcifying solution (Baxter Scientific Products)
Ethylenediaminetetraacetic Acid,
Tetrasodium......................................................0.7 g/l
Sodium Potassium Tartrate...................................8.0 mg/liter
Hydrochloric Acid...........................................99.2 g/liter
Sodium Tartrate.............................................0.14 g/liter
(q) Tetrahydrofuran (THF)
(r) Hotplate capable of 60 [deg]C
(s) Balance
(t) Hacksaw blade
(u) Ruby mortar and pestle
3.3. Sample Pre-Preparation
Sample preparation begins with pre-preparation which may include
chemical reduction of the matrix, heating the sample to dryness or
heating in the muffle furnace. The end result is a sample which has been
reduced to a powder that is sufficiently fine to fit under the cover
slip. Analyze different phases of samples separately, e.g., tile and the
tile mastic should be analyzed separately as the mastic may contain
asbestos while the tile may not.
(a) Wet Samples
Samples with a high water content will not give the proper
dispersion colors and must be dried prior to sample mounting. Remove the
lid of the scintillation vial, place the bottle in the drying oven and
heat at 100 [deg]C to dryness (usually about 2 h). Samples which are not
submitted to the lab in glass must be removed and placed in glass vials
or aluminum weighing pans before placing them in the drying oven.
(b) Samples With Organic Interference--Muffle Furnace
These may include samples with tar as a matrix, vinyl asbestos tile,
or any other organic that can be reduced by heating. Remove the sample
from the vial and weigh in a balance to determine the weight of the
submitted portion. Place the sample in a muffle furnace at 500 [deg]C
for 1 to 2 h or until all obvious organic material has been removed.
Retrieve, cool and weigh again to determine the weight loss on ignition.
This is necessary to determine the asbestos content of the submitted
sample, because the analyst will be looking at a reduced sample.
Notes: Heating above 600 [deg]C will cause the sample to undergo a
structural change which, given sufficient time, will convert the
chrysotile to forsterite. Heating even at lower temperatures for 1 to 2
h may have a measurable effect on the optical properties of the
minerals. If the analyst is unsure of what to expect, a sample of
standard asbestos should be heated to the same temperature for the same
length of time so that it can be examined for the proper interpretation.
(c) Samples With Organic Interference--THF
Vinyl asbestos tile is the most common material treated with this
solvent, although, substances containing tar will sometimes yield to
this treatment. Select a portion of the material and then grind it up if
possible. Weigh the sample and place it in a test tube. Add sufficient
THF to dissolve the organic matrix. This is usually about 4 to 5 mL.
Remember, THF is highly flammable. Filter the remaining material through
a tared silver
[[Page 188]]
membrane, dry and weigh to determine how much is left after the solvent
extraction. Further process the sample to remove carbonate or mount
directly.
(d) Samples With Carbonate Interference
Carbonate material is often found on fibers and sometimes must be
removed in order to perform dispersion microscopy. Weigh out a portion
of the material and place it in a test tube. Add a sufficient amount of
0.1 M HCl or decalcifying solution in the tube to react all the
carbonate as evidenced by gas formation; i.e., when the gas bubbles
stop, add a little more solution. If no more gas forms, the reaction is
complete. Filter the material out through a tared silver membrane, dry
and weigh to determine the weight lost.
3.4. Sample Preparation
Samples must be prepared so that accurate determination can be made
of the asbestos type and amount present. The following steps are carried
out in the low-flow hood (a low-flow hood has less than 50 fpm flow):
(1) If the sample has large lumps, is hard, or cannot be made to lie
under a cover slip, the grain size must be reduced. Place a small amount
between two slides and grind the material between them or grind a small
amount in a clean mortar and pestle. The choice of whether to use an
alumina, ruby, or diamond mortar depends on the hardness of the
material. Impact damage can alter the asbestos mineral if too much
mechanical shock occurs. (Freezer mills can completely destroy the
observable crystallinity of asbestos and should not be used). For some
samples, a portion of material can be shaved off with a scalpel, ground
off with a hand grinder or hack saw blade.
The preparation tools should either be disposable or cleaned
thoroughly. Use vigorous scrubbing to loosen the fibers during the
washing. Rinse the implements with copious amounts of water and air-dry
in a dust-free environment.
(2) If the sample is powder or has been reduced as in 1) above, it
is ready to mount. Place a glass slide on a piece of optical tissue and
write the identification on the painted or frosted end. Place two drops
of index of refraction medium n=1.550 on the slide. (The medium n=1.550
is chosen because it is the matching index for chrysotile. Dip the end
of a clean paper-clip or dissecting needle into the droplet of
refraction medium on the slide to moisten it. Then dip the probe into
the powder sample. Transfer what sticks on the probe to the slide. The
material on the end of the probe should have a diameter of about 3 mm
for a good mount. If the material is very fine, less sample may be
appropriate. For non-powder samples such as fiber mats, forceps should
be used to transfer a small amount of material to the slide. Stir the
material in the medium on the slide, spreading it out and making the
preparation as uniform as possible. Place a cover-slip on the
preparation by gently lowering onto the slide and allowing it to fall
``trapdoor'' fashion on the preparation to push out any bubbles. Press
gently on the cover slip to even out the distribution of particulate on
the slide. If there is insufficient mounting oil on the slide, one or
two drops may be placed near the edge of the coverslip on the slide.
Capillary action will draw the necessary amount of liquid into the
preparation. Remove excess oil with the point of a laboratory wiper.
Treat at least two different areas of each phase in this fashion.
Choose representative areas of the sample. It may be useful to select
particular areas or fibers for analysis. This is useful to identify
asbestos in severely inhomogeneous samples.
When it is determined that amphiboles may be present, repeat the
above process using the appropriate high- dispersion oils until an
identification is made or all six asbestos minerals have been ruled out.
Note that percent determination must be done in the index medium 1.550
because amphiboles tend to disappear in their matching mediums.
3.5. Analytical procedure
Note: This method presumes some knowledge of mineralogy and optical
petrography.
The analysis consists of three parts: The determination of whether
there is asbestos present, what type is present and the determination of
how much is present. The general flow of the analysis is:
(1) Gross examination.
(2) Examination under polarized light on the stereo microscope.
(3) Examination by phase-polar illumination on the compound phase
microscope.
(4) Determination of species by dispersion stain. Examination by
Becke line analysis may also be used; however, this is usually more
cumbersome for asbestos determination.
(5) Difficult samples may need to be analyzed by SEM or TEM, or the
results from those techniques combined with light microscopy for a
definitive identification. Identification of a particle as asbestos
requires that it be asbestiform. Description of particles should follow
the suggestion of Campbell. (Figure 1)
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[GRAPHIC] [TIFF OMITTED] TR10AU94.024
For the purpose of regulation, the mineral must be one of the six
minerals covered and must be in the asbestos growth habit. Large
specimen samples of asbestos generally have the gross appearance of
wood. Fibers are easily parted from it. Asbestos fibers are very long
compared with their widths. The fibers
[[Page 190]]
have a very high tensile strength as demonstrated by bending without
breaking. Asbestos fibers exist in bundles that are easily parted, show
longitudinal fine structure and may be tufted at the ends showing
``bundle of sticks'' morphology. In the microscope some of these
properties may not be observable. Amphiboles do not always show
striations along their length even when they are asbestos. Neither will
they always show tufting. They generally do not show a curved nature
except for very long fibers. Asbestos and asbestiform minerals are
usually characterized in groups by extremely high aspect ratios (greater
than 100:1). While aspect ratio analysis is useful for characterizing
populations of fibers, it cannot be used to identify individual fibers
of intermediate to short aspect ratio. Observation of many fibers is
often necessary to determine whether a sample consists of ``cleavage
fragments'' or of asbestos fibers.
Most cleavage fragments of the asbestos minerals are easily
distinguishable from true asbestos fibers. This is because true cleavage
fragments usually have larger diameters than 1 [micro]m. Internal
structure of particles larger than this usually shows them to have no
internal fibrillar structure. In addition, cleavage fragments of the
monoclinic amphiboles show inclined extinction under crossed polars with
no compensator. Asbestos fibers usually show extinction at zero degrees
or ambiguous extinction if any at all. Morphologically, the larger
cleavage fragments are obvious by their blunt or stepped ends showing
prismatic habit. Also, they tend to be acicular rather than filiform.
Where the particles are less than 1 [micro]m in diameter and have an
aspect ratio greater than or equal to 3:1, it is recommended that the
sample be analyzed by SEM or TEM if there is any question whether the
fibers are cleavage fragments or asbestiform particles.
Care must be taken when analyzing by electron microscopy because the
interferences are different from those in light microscopy and may
structurally be very similar to asbestos. The classic interference is
between anthophyllite and biopyribole or intermediate fiber. Use the
same morphological clues for electron microscopy as are used for light
microscopy, e.g. fibril splitting, internal longitudinal striation,
fraying, curvature, etc.
(1) Gross examination:
Examine the sample, preferably in the glass vial. Determine the
presence of any obvious fibrous component. Estimate a percentage based
on previous experience and current observation. Determine whether any
pre-preparation is necessary. Determine the number of phases present.
This step may be carried out or augmented by observation at 6 to 40x
under a stereo microscope.
(2) After performing any necessary pre-preparation, prepare slides
of each phase as described above. Two preparations of the same phase in
the same index medium can be made side-by-side on the same glass for
convenience. Examine with the polarizing stereo microscope. Estimate the
percentage of asbestos based on the amount of birefringent fiber
present.
(3) Examine the slides on the phase-polar microscopes at
magnifications of 160 and 400x. Note the morphology of the fibers. Long,
thin, very straight fibers with little curvature are indicative of
fibers from the amphibole family. Curved, wavy fibers are usually
indicative of chrysotile. Estimate the percentage of asbestos on the
phase-polar microscope under conditions of crossed polars and a gypsum
plate. Fibers smaller than 1.0 [micro]m in thickness must be identified
by inference to the presence of larger, identifiable fibers and
morphology. If no larger fibers are visible, electron microscopy should
be performed. At this point, only a tentative identification can be
made. Full identification must be made with dispersion microscopy.
Details of the tests are included in the appendices.
(4) Once fibers have been determined to be present, they must be
identified. Adjust the microscope for dispersion mode and observe the
fibers. The microscope has a rotating stage, one polarizing element, and
a system for generating dark-field dispersion microscopy (see Section
4.6. of this appendix). Align a fiber with its length parallel to the
polarizer and note the color of the Becke lines. Rotate the stage to
bring the fiber length perpendicular to the polarizer and note the
color. Repeat this process for every fiber or fiber bundle examined. The
colors must be consistent with the colors generated by standard asbestos
reference materials for a positive identification. In n=1.550,
amphiboles will generally show a yellow to straw-yellow color indicating
that the fiber indices of refraction are higher than the liquid. If
long, thin fibers are noted and the colors are yellow, prepare further
slides as above in the suggested matching liquids listed below:
------------------------------------------------------------------------
Type of asbestos Index of refraction
------------------------------------------------------------------------
Chrysotile.......................... n=1.550.
Amosite............................. n=1.670 r 1.680.
Crocidolite......................... n=1.690.
Anthophyllite....................... n=1.605 nd 1.620.
Tremolite........................... n=1.605 and 1.620.
Actinolite.......................... n=1.620.
------------------------------------------------------------------------
Where more than one liquid is suggested, the first is preferred;
however, in some cases this liquid will not give good dispersion color.
Take care to avoid interferences in the other liquid; e.g., wollastonite
in n=1.620 will give the same colors as tremolite. In n=1.605
wollastonite will appear yellow in all directions. Wollastonite may be
determined under crossed polars as it will change from blue to
[[Page 191]]
yellow as it is rotated along its fiber axis by tapping on the cover
slip. Asbestos minerals will not change in this way.
Determination of the angle of extinction may, when present, aid in
the determination of anthophyllite from tremolite. True asbestos fibers
usually have 0[deg] extinction or ambiguous extinction, while cleavage
fragments have more definite extinction.
Continue analysis until both preparations have been examined and all
present species of asbestos are identified. If there are no fibers
present, or there is less than 0.1% present, end the analysis with the
minimum number of slides (2).
(5) Some fibers have a coating on them which makes dispersion
microscopy very difficult or impossible. Becke line analysis or electron
microscopy may be performed in those cases. Determine the percentage by
light microscopy. TEM analysis tends to overestimate the actual
percentage present.
(6) Percentage determination is an estimate of occluded area,
tempered by gross observation. Gross observation information is used to
make sure that the high magnification microscopy does not greatly over-
or under-estimate the amount of fiber present. This part of the analysis
requires a great deal of experience. Satisfactory models for asbestos
content analysis have not yet been developed, although some models based
on metallurgical grain-size determination have found some utility.
Estimation is more easily handled in situations where the grain sizes
visible at about 160x are about the same and the sample is relatively
homogeneous.
View all of the area under the cover slip to make the percentage
determination. View the fields while moving the stage, paying attention
to the clumps of material. These are not usually the best areas to
perform dispersion microscopy because of the interference from other
materials. But, they are the areas most likely to represent the accurate
percentage in the sample. Small amounts of asbestos require slower
scanning and more frequent analysis of individual fields.
Report the area occluded by asbestos as the concentration. This
estimate does not generally take into consideration the difference in
density of the different species present in the sample. For most samples
this is adequate. Simulation studies with similar materials must be
carried out to apply microvisual estimation for that purpose and is
beyond the scope of this procedure.
(7) Where successive concentrations have been made by chemical or
physical means, the amount reported is the percentage of the material in
the ``as submitted'' or original state. The percentage determined by
microscopy is multiplied by the fractions remaining after pre-
preparation steps to give the percentage in the original sample. For
example:
Step 1. 60% remains after heating at 550 [deg]C for 1 h.
Step 2. 30% of the residue of step 1 remains after dissolution of
carbonate in 0.1 m HCl.
Step 3. Microvisual estimation determines that 5% of the sample is
chrysotile asbestos.
The reported result is:
R = (Microvisual result in percent)x(Fraction remaining after step
2)x(Fraction remaining of original sample after step 1)
R = (5)x(.30)x(.60) = 0.9%
(8) Report the percent and type of asbestos present. For samples
where asbestos was identified, but is less than 1.0%, report ``Asbestos
present, less than 1.0%.'' There must have been at least two observed
fibers or fiber bundles in the two preparations to be reported as
present. For samples where asbestos was not seen, report as ``None
Detected.''
4. Auxiliary Information
Because of the subjective nature of asbestos analysis, certain
concepts and procedures need to be discussed in more depth. This
information will help the analyst understand why some of the procedures
are carried out the way they are.
4.1. Light
Light is electromagnetic energy. It travels from its source in
packets called quanta. It is instructive to consider light as a plane
wave. The light has a direction of travel. Perpendicular to this and
mutually perpendicular to each other, are two vector components. One is
the magnetic vector and the other is the electric vector. We shall only
be concerned with the electric vector. In this description, the
interaction of the vector and the mineral will describe all the
observable phenomena. From a light source such a microscope illuminator,
light travels in all different direction from the filament.
In any given direction away from the filament, the electric vector
is perpendicular to the direction of travel of a light ray. While
perpendicular, its orientation is random about the travel axis. If the
electric vectors from all the light rays were lined up by passing the
light through a filter that would only let light rays with electric
vectors oriented in one direction pass, the light would then be
POLARIZED.
Polarized light interacts with matter in the direction of the
electric vector. This is the polarization direction. Using this property
it is possible to use polarized light to probe different materials and
identify them by how they interact with light. The speed of light in a
vacuum is a constant at about 2.99x10 \8\ m/s. When light travels in
different materials such as air, water, minerals or oil, it does not
travel at this speed. It travels slower. This slowing is a function of
both the
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material through which the light is traveling and the wavelength or
frequency of the light. In general, the more dense the material, the
slower the light travels. Also, generally, the higher the frequency, the
slower the light will travel. The ratio of the speed of light in a
vacuum to that in a material is called the index of refraction (n). It
is usually measured at 589 nm (the sodium D line). If white light (light
containing all the visible wavelengths) travels through a material, rays
of longer wavelengths will travel faster than those of shorter
wavelengths, this separation is called dispersion. Dispersion is used as
an identifier of materials as described in Section 4.6.
4.2. Material Properties
Materials are either amorphous or crystalline. The difference
between these two descriptions depends on the positions of the atoms in
them. The atoms in amorphous materials are randomly arranged with no
long range order. An example of an amorphous material is glass. The
atoms in crystalline materials, on the other hand, are in regular arrays
and have long range order. Most of the atoms can be found in highly
predictable locations. Examples of crystalline material are salt, gold,
and the asbestos minerals.
It is beyond the scope of this method to describe the different
types of crystalline materials that can be found, or the full
description of the classes into which they can fall. However, some
general crystallography is provided below to give a foundation to the
procedures described.
With the exception of anthophyllite, all the asbestos minerals
belong to the monoclinic crystal type. The unit cell is the basic
repeating unit of the crystal and for monoclinic crystals can be
described as having three unequal sides, two 90[deg] angles and one
angle not equal to 90[deg]. The orthorhombic group, of which
anthophyllite is a member has three unequal sides and three 90[deg]
angles. The unequal sides are a consequence of the complexity of fitting
the different atoms into the unit cell. Although the atoms are in a
regular array, that array is not symmetrical in all directions. There is
long range order in the three major directions of the crystal. However,
the order is different in each of the three directions. This has the
effect that the index of refraction is different in each of the three
directions. Using polarized light, we can investigate the index of
refraction in each of the directions and identify the mineral or
material under investigation. The indices [alpha], [beta], and [gamma]
are used to identify the lowest, middle, and highest index of refraction
respectively. The x direction, associated with [alpha] is called the
fast axis. Conversely, the z direction is associated with [gamma] and is
the slow direction. Crocidolite has [alpha] along the fiber length
making it ``length-fast''. The remainder of the asbestos minerals have
the [gamma] axis along the fiber length. They are called ``length-
slow''. This orientation to fiber length is used to aid in the
identification of asbestos.
4.3. Polarized Light Technique
Polarized light microscopy as described in this section uses the
phase-polar microscope described in Section 3.2. A phase contrast
microscope is fitted with two polarizing elements, one below and one
above the sample. The polarizers have their polarization directions at
right angles to each other. Depending on the tests performed, there may
be a compensator between these two polarizing elements. Light emerging
from a polarizing element has its electric vector pointing in the
polarization direction of the element. The light will not be
subsequently transmitted through a second element set at a right angle
to the first element. Unless the light is altered as it passes from one
element to the other, there is no transmission of light.
4.4. Angle of Extinction
Crystals which have different crystal regularity in two or three
main directions are said to be anisotropic. They have a different index
of refraction in each of the main directions. When such a crystal is
inserted between the crossed polars, the field of view is no longer dark
but shows the crystal in color. The color depends on the properties of
the crystal. The light acts as if it travels through the crystal along
the optical axes. If a crystal optical axis were lined up along one of
the polarizing directions (either the polarizer or the analyzer) the
light would appear to travel only in that direction, and it would blink
out or go dark. The difference in degrees between the fiber direction
and the angle at which it blinks out is called the angle of extinction.
When this angle can be measured, it is useful in identifying the
mineral. The procedure for measuring the angle of extinction is to first
identify the polarization direction in the microscope. A commercial
alignment slide can be used to establish the polarization directions or
use anthophyllite or another suitable mineral. This mineral has a zero
degree angle of extinction and will go dark to extinction as it aligns
with the polarization directions. When a fiber of anthophyllite has gone
to extinction, align the eyepiece reticle or graticule with the fiber so
that there is a visual cue as to the direction of polarization in the
field of view. Tape or otherwise secure the eyepiece in this position so
it will not shift.
After the polarization direction has been identified in the field of
view, move the particle of interest to the center of the field of
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view and align it with the polarization direction. For fibers, align the
fiber along this direction. Note the angular reading of the rotating
stage. Looking at the particle, rotate the stage until the fiber goes
dark or ``blinks out''. Again note the reading of the stage. The
difference in the first reading and the second is an angle of
extinction.
The angle measured may vary as the orientation of the fiber changes
about its long axis. Tables of mineralogical data usually report the
maximum angle of extinction. Asbestos forming minerals, when they
exhibit an angle of extinction, usually do show an angle of extinction
close to the reported maximum, or as appropriate depending on the
substitution chemistry.
4.5. Crossed Polars With Compensator
When the optical axes of a crystal are not lined up along one of the
polarizing directions (either the polarizer or the analyzer) part of the
light travels along one axis and part travels along the other visible
axis. This is characteristic of birefringent materials.
The color depends on the difference of the two visible indices of
refraction and the thickness of the crystal. The maximum difference
available is the difference between the [alpha] and the [gamma] axes.
This maximum difference is usually tabulated as the birefringence of the
crystal.
For this test, align the fiber at 45[deg] to the polarization
directions in order to maximize the contribution to each of the optical
axes. The colors seen are called retardation colors. They arise from the
recombination of light which has traveled through the two separate
directions of the crystal. One of the rays is retarded behind the other
since the light in that direction travels slower. On recombination, some
of the colors which make up white light are enhanced by constructive
interference and some are suppressed by destructive interference. The
result is a color dependent on the difference between the indices and
the thickness of the crystal. The proper colors, thicknesses, and
retardations are shown on a Michel-Levy chart. The three items,
retardation, thickness and birefringence are related by the following
relationship:
R = t(n[gamma]--[alpha])
R = retardation, t = crystal thickness in [micro]m, and
[alpha],[gamma] = indices of refraction.
Examination of the equation for asbestos minerals reveals that the
visible colors for almost all common asbestos minerals and fiber sizes
are shades of gray and black. The eye is relatively poor at
discriminating different shades of gray. It is very good at
discriminating different colors. In order to compensate for the low
retardation, a compensator is added to the light train between the
polarization elements. The compensator used for this test is a gypsum
plate of known thickness and birefringence. Such a compensator when
oriented at 45[deg] to the polarizer direction, provides a retardation
of 530 nm of the 530 nm wavelength color. This enhances the red color
and gives the background a characteristic red to red-magenta color. If
this ``full-wave'' compensator is in place when the asbestos preparation
is inserted into the light train, the colors seen on the fibers are
quite different. Gypsum, like asbestos has a fast axis and a slow axis.
When a fiber is aligned with its fast axis in the same direction as the
fast axis of the gypsum plate, the ray vibrating in the slow direction
is retarded by both the asbestos and the gypsum. This results in a
higher retardation than would be present for either of the two minerals.
The color seen is a second order blue. When the fiber is rotated 90[deg]
using the rotating stage, the slow direction of the fiber is now aligned
with the fast direction of the gypsum and the fast direction of the
fiber is aligned with the slow direction of the gypsum. Thus, one ray
vibrates faster in the fast direction of the gypsum, and slower in the
slow direction of the fiber; the other ray will vibrate slower in the
slow direction of the gypsum and faster in the fast direction of the
fiber. In this case, the effect is subtractive and the color seen is a
first order yellow. As long as the fiber thickness does not add
appreciably to the color, the same basic colors will be seen for all
asbestos types except crocidolite. In crocidolite the colors will be
weaker, may be in the opposite directions, and will be altered by the
blue absorption color natural to crocidolite. Hundreds of other
materials will give the same colors as asbestos, and therefore, this
test is not definitive for asbestos. The test is useful in
discriminating against fiberglass or other amorphous fibers such as some
synthetic fibers. Certain synthetic fibers will show retardation colors
different than asbestos; however, there are some forms of polyethylene
and aramid which will show morphology and retardation colors similar to
asbestos minerals. This test must be supplemented with a positive
identification test when birefringent fibers are present which can not
be excluded by morphology. This test is relatively ineffective for use
on fibers less than 1 [micro]m in diameter. For positive confirmation
TEM or SEM should be used if no larger bundles or fibers are visible.
4.6. Dispersion Staining
Dispersion microscopy or dispersion staining is the method of choice
for the identification of asbestos in bulk materials. Becke line
analysis is used by some laboratories and yields the same results as
does dispersion staining for asbestos and can be used in lieu of
dispersion staining. Dispersion staining is performed on the same
platform as the
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phase-polar analysis with the analyzer and compensator removed. One
polarizing element remains to define the direction of the light so that
the different indices of refraction of the fibers may be separately
determined. Dispersion microscopy is a dark-field technique when used
for asbestos. Particles are imaged with scattered light. Light which is
unscattered is blocked from reaching the eye either by the back field
image mask in a McCrone objective or a back field image mask in the
phase condenser. The most convenient method is to use the rotating phase
condenser to move an oversized phase ring into place. The ideal size for
this ring is for the central disk to be just larger than the objective
entry aperture as viewed in the back focal plane. The larger the disk,
the less scattered light reaches the eye. This will have the effect of
diminishing the intensity of dispersion color and will shift the actual
color seen. The colors seen vary even on microscopes from the same
manufacturer. This is due to the different bands of wavelength exclusion
by different mask sizes. The mask may either reside in the condenser or
in the objective back focal plane. It is imperative that the analyst
determine by experimentation with asbestos standards what the
appropriate colors should be for each asbestos type. The colors depend
also on the temperature of the preparation and the exact chemistry of
the asbestos. Therefore, some slight differences from the standards
should be allowed. This is not a serious problem for commercial asbestos
uses. This technique is used for identification of the indices of
refraction for fibers by recognition of color. There is no direct
numerical readout of the index of refraction. Correlation of color to
actual index of refraction is possible by referral to published
conversion tables. This is not necessary for the analysis of asbestos.
Recognition of appropriate colors along with the proper morphology are
deemed sufficient to identify the commercial asbestos minerals. Other
techniques including SEM, TEM, and XRD may be required to provide
additional information in order to identify other types of asbestos.
Make a preparation in the suspected matching high dispersion oil,
e.g., n=1.550 for chrysotile. Perform the preliminary tests to determine
whether the fibers are birefringent or not. Take note of the
morphological character. Wavy fibers are indicative of chrysotile while
long, straight, thin, frayed fibers are indicative of amphibole
asbestos. This can aid in the selection of the appropriate matching oil.
The microscope is set up and the polarization direction is noted as in
Section 4.4. Align a fiber with the polarization direction. Note the
color. This is the color parallel to the polarizer. Then rotate the
fiber rotating the stage 90[deg] so that the polarization direction is
across the fiber. This is the perpendicular position. Again note the
color. Both colors must be consistent with standard asbestos minerals in
the correct direction for a positive identification of asbestos. If only
one of the colors is correct while the other is not, the identification
is not positive. If the colors in both directions are bluish-white, the
analyst has chosen a matching index oil which is higher than the correct
matching oil, e.g. the analyst has used n = 1.620 where chrysotile is
present. The next lower oil (Section 3.5.) should be used to prepare
another specimen. If the color in both directions is yellow-white to
straw-yellow-white, this indicates that the index of the oil is lower
than the index of the fiber, e.g. the preparation is in n = 1.550 while
anthophyllite is present. Select the next higher oil (Section 3.5.) and
prepare another slide. Continue in this fashion until a positive
identification of all asbestos species present has been made or all
possible asbestos species have been ruled out by negative results in
this test. Certain plant fibers can have similar dispersion colors as
asbestos. Take care to note and evaluate the morphology of the fibers or
remove the plant fibers in pre-preparation. Coating material on the
fibers such as carbonate or vinyl may destroy the dispersion color.
Usually, there will be some outcropping of fiber which will show the
colors sufficient for identification. When this is not the case, treat
the sample as described in Section 3.3. and then perform dispersion
staining. Some samples will yield to Becke line analysis if they are
coated or electron microscopy can be used for identification.
5. References
5.1. Crane, D.T., Asbestos in Air, OSHA method ID160, Revised
November 1992.
5.2. Ford, W.E., Dana's Textbook of Mineralogy; Fourth Ed.; John
Wiley and Son, New York, 1950, p. vii.
5.3. Selikoff,.I.J., Lee, D.H.K., Asbestos and Disease, Academic
Press, New York, 1978, pp. 3, 20.
5.4. Women Inspectors of Factories. Annual Report for 1898, H.M.
Statistical Office, London, p. 170 (1898).
5.5. Selikoff,.I.J., Lee, D.H.K., Asbestos and Disease, Academic
Press, New York, 1978, pp. 26, 30.
5.6. Campbell, W.J., et al, Selected Silicate Minerals and Their
Asbestiform Varieties, United States Department of the Interior, Bureau
of Mines, Information Circular 8751, 1977.
5.7. Asbestos, Code of Federal Regulations, 29 CFR 1910.1001 and 29
CFR 1926.58.
5.8. National Emission Standards for Hazardous Air Pollutants;
Asbestos NESHAP Revision, Federal Register, Vol. 55, No. 224, 20
November 1990, p. 48410.
5.9. Ross, M. The Asbestos Minerals: Definitions, Description, Modes
of Formation, Physical and Chemical Properties and Health Risk to
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the Mining Community, Nation Bureau of Standards Special Publication,
Washington, D.C., 1977.
5.10. Lilis, R., Fibrous Zeolites and Endemic Mesothelioma in
Cappadocia, Turkey, J. Occ Medicine, 1981, 23, (8) ,548-550.
5.11. Occupational Exposure to Asbestos--1972, U.S. Department of
Health Education and Welfare, Public Health Service, Center for Disease
Control, National Institute for Occupational Safety and Health, HSM-72-
10267.
5.12. Campbell,W.J., et al, Relationship of Mineral Habit to Size
Characteristics for Tremolite Fragments and Fibers, United States
Department of the Interior, Bureau of Mines, Information Circular 8367,
1979.
5.13. Mefford, D., DCM Laboratory, Denver, private communication,
July 1987.
5.14. Deer, W.A., Howie, R.A., Zussman, J., Rock Forming Minerals,
Longman, Thetford, UK, 1974.
5.15. Kerr, P.F., Optical Mineralogy; Third Ed. McGraw-Hill, New
York, 1959.
5.16. Veblen, D.R. (Ed.), Amphiboles and Other Hydrous Pyriboles--
Mineralogy, Reviews in Mineralogy, Vol 9A, Michigan, 1982, pp 1-102.
5.17. Dixon, W.C., Applications of Optical Microscopy in the
Analysis of Asbestos and Quartz, ACS Symposium Series, No. 120,
Analytical Techniques in Occupational Health Chemistry, 1979.
5.18. Polarized Light Microscopy, McCrone Research Institute,
Chicago, 1976.
5.19. Asbestos Identification, McCrone Research Institute, G & G
printers, Chicago, 1987.
5.20. McCrone, W.C., Calculation of Refractive Indices from
Dispersion Staining Data, The Microscope, No 37, Chicago, 1989.
5.21. Levadie, B. (Ed.), Asbestos and Other Health Related
Silicates, ASTM Technical Publication 834, ASTM, Philadelphia 1982.
5.22. Steel, E. and Wylie, A., Riordan, P.H. (Ed.), Mineralogical
Characteristics of Asbestos, Geology of Asbestos Deposits, pp. 93-101,
SME-AIME, 1981.
5.23. Zussman, J., The Mineralogy of Asbestos, Asbestos: Properties,
Applications and Hazards, pp. 45-67 Wiley, 1979.
Appendix L to Sec. 1915.1001--Work Practices and Engineering Controls
for Automotive Brake and Clutch Inspection, Disassembly, Repair and
Assembly--Mandatory
This mandatory appendix specifies engineering controls and work
practices that must be implemented by the employer during automotive
brake and clutch inspection, disassembly, repair, and assembly
operations. Proper use of these engineering controls and work practices
by trained employees will reduce employees' asbestos exposure below the
permissible exposure level during clutch and brake inspection,
disassembly, repair, and assembly operations. The employer shall
institute engineering controls and work practices using either the
method set forth in paragraph [A] or paragraph [B] of this appendix, or
any other method which the employer can demonstrate to be equivalent in
terms of reducing employee exposure to asbestos as defined and which
meets the requirements described in paragraph [C] of this appendix, for
those facilities in which no more than 5 pairs of brakes or 5 clutches
are inspected, disassembled, reassembled and/or repaired per week, the
method set forth in paragraph [D] of this appendix may be used:
[A] Negative Pressure Enclosure/HEPA Vacuum System Method
(1) The brake and clutch inspection, disassembly, repair, and
assembly operations shall be enclosed to cover and contain the clutch or
brake assembly and to prevent the release of asbestos fibers into the
worker's breathing zone.
(2) The enclosure shall be sealed tightly and thoroughly inspected
for leaks before work begins on brake and clutch inspection,
disassembly, repair, and assembly.
(3) The enclosure shall be such that the worker can clearly see the
operation and shall provide impermeable sleeves through which the worker
can handle the brake and clutch inspection, disassembly, repair and
assembly. The integrity of the sleeves and ports shall be examined
before work begins.
(4) A HEPA-filtered vacuum shall be employed to maintain the
enclosure under negative pressure throughout the operation. Compressed-
air may be used to remove asbestos fibers or particles from the
enclosure.
(5) The HEPA vacuum shall be used first to loosen the asbestos
containing residue from the brake and clutch parts and then to evacuate
the loosened asbestos containing material from the enclosure and capture
the material in the vacuum filter.
(6) The vacuum's filter, when full, shall be first wetted with a
fine mist of water, then removed and placed immediately in an
impermeable container, labeled according to paragraph (k)(8) of this
section and disposed of according to paragraph (l) of this section.
(7) Any spills or releases of asbestos containing waste material
from inside of the enclosure or vacuum hose or vacuum filter shall be
immediately cleaned up and disposed of according to paragraph (l) of the
section.
[B] Low Pressure/Wet Cleaning Method
(1) A catch basin shall be placed under the brake assembly,
positioned to avoid splashes and spills.
(2) The reservoir shall contain water containing an organic solvent
or wetting agent. The flow of liquid shall be controlled such that the
brake assembly is gently flooded to
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prevent the asbestos-containing brake dust from becoming airborne.
(3) The aqueous solution shall be allowed to flow between the brake
drum and brake support before the drum is removed.
(4) After removing the brake drum, the wheel hub and back of the
brake assembly shall be thoroughly wetted to suppress dust.
(5) The brake support plate, brake shoes and brake components used
to attach the brake shoes shall be thoroughly washed before removing the
old shoes.
(6) In systems using filters, the filters, when full, shall be first
wetted with a fine mist of water, then removed and placed immediately in
an impermeable container, labeled according to paragraph (k)(8) of this
section and disposed of according to paragraph (l) of this section.
(7) Any spills of asbestos-containing aqueous solution or any
asbestos-containing waste material shall be cleaned up immediately and
disposed of according to paragraph (l) of this section.
(8) The use of dry brushing during low pressure/wet cleaning
operations is prohibited.
[C] Equivalent Methods
An equivalent method is one which has sufficient written detail so
that it can be reproduced and has been demonstrated that the exposures
resulting from the equivalent method are equal to or less than the
exposures which would result from the use of the method described in
paragraph [A] of this appendix. For purposes of making this comparison,
the employer shall assume that exposures resulting from the use of the
method described in paragraph [A] of this appendix shall not exceed
0.016 f/cc, as measured by the OSHA reference method and as averaged
over at least 18 personal samples.
[D] Wet Method
(1) A spray bottle, hose nozzle, or other implement capable of
delivering a fine mist of water or amended water or other delivery
system capable of delivering water at low pressure, shall be used to
first thoroughly wet the brake and clutch parts. Brake and clutch
components shall then be wiped clean with a cloth.
(2) The cloth shall be placed in an impermeable container, labelled
according to paragraph (k)(8) of this section and then disposed of
according to paragraph (l) of this section, or the cloth shall be
laundered in a way to prevent the release of asbestos fibers in excess
of 0.1 fiber per cubic centimeter of air.
(3) Any spills of solvent or any asbestos containing waste material
shall be cleaned up immediately according to paragraph (l) of this
section.
(4) The use of dry brushing during the wet method operations is
prohibited.
[59 FR 41080, Aug. 10, 1994, as amended at 60 FR 33344, June 28, 1995;
60 FR 33987-33995, June 29, 1995; 60 FR 36044, July 13, 1995; 60 FR
50412, Sept. 29, 1995; 61 FR 43457, Aug. 23, 1996; 63 FR 35137, June 29,
1998; 67 FR 44545, 44546, July 3, 2002; 70 FR 1143, Jan. 5, 2005]