A PORK SLAUGHTER OPERATION

Occupational Safety & Health Administration

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A PORK SLAUGHTER OPERATION
INTRODUCTION

The video tape was analyzed to determine the potential for upper extremity cumulative trauma disorders (UECTDs), lower extremity cumulative trauma disorders (LECTDs), and low back problems. Cumulative trauma disorders and low back problems are serious conditions. While there is frequently no external sign of a disorder (as with cuts, contusions, etc.) these conditions are painful and can significantly affect both the occupational and non-occupational life of the person exposed. In addition, since they are cumulative disorders, if the task characteristics remain unchanged, the cumulative deterioration of the affected body part will frequently continue until irreversible damage is done. During the video tape analysis it was noted that the forces, repetitions, postures, and lifting tasks filmed had the potential to cause UECTDs and low back pain.

High finger or grip forces, frequent repetition with short rest periods, awkward body posture (flexed and extended wrist, elbow above mid-torso, etc.), and fatigue are factors which are associated with the development of UECTDs. These factors can cause irritation of the tendons, tendon sheathes, and nerves in the arms and hands. When these factors exist simultaneously the hazard is significantly increased. In addition, tendon and nerve irritations can be caused by direct contact of the upper extremities with tools and hard surfaces. Musculoskeletal problems at the shoulder may also result from the excessive shoulder moments generated when loads are lifted or held away from the body.

The development of low back problems is often associated with the magnitude and duration of spinal compressive loads, and frequent repetition of the manual material handling activity. Spinal compressive forces result from the load or force in the hands and the distance that the load is held away from the body. In addition, the potential for low back problems increases substantially when there is torso twisting during the lifting or load movement. Constrained postures during lifts, the handling of bulky loads, and poor contact between the hands and the loads also increases the hazard potential for low back problems. Frequent repetition with short rest, awkward body posture (flexed and extended wrists, elbow above mid-torso, twisted trunk, etc.) and fatigue are all factors which have been associated with the development of cumulative trauma disorders.

Specific hazards observed in the operations are listed along with recommended corrective actions whenever possible. In addition some of the hazards and controls are covered under general abatement strategies.

This report should not be considered a full ergonomic evaluation of the operations observed nor were all hazardous operations necessarily addressed. A full ergonomic evaluation should include the services of a properly trained ergonomist since proper intervention requires a variety of approaches and must be implemented over a period of time. This report discusses only engineering and work practice controls which can be implemented to reduce the potential for musculoskeletal disorders in the operations which were reviewed. These are not the only possible solutions and any solution has to be implemented and evaluated to prove its effectiveness. Employee participation and involvement is necessary to properly design engineering controls to minimize the hazards of UECTD and low back pain.

Not all recommended controls need necessarily be implemented for each employee in the operations evaluated. It is understood that often more than one operator uses these work stations and often operators have alternate jobs which may also contribute to the problems. The appearance of injuries and illness are often dependent on the anthropometry of the employee, the training received by the employee, and the employee's work practices including their rate of work. The recommendations are not all inclusive and a more in-depth study may be required to determine safe operating parameters for particular employees. Other factors which should be included for any program to be effective include employee training and participation in planning, ergonomic abatement committees, supervisor training, hazard analysis, administrative controls, and medical monitoring.

GENERAL ABATEMENT STRATEGIES

Engineering and Administrative Controls

Consultant Assistance

Medical Management Program

Training programs

the elbow is above mid-torso
the hand is above the shoulder
the arms must reach behind the torso

inward or outward rotation with bent wrist
excessive palmer flexion or extension
ulnar or radial deviation
pinching or high finger forces with above postures

keep the load close to the body
use the most comfortable posture
lift slowly and evenly (don't jerk)
do not twist the back
securely grip the load
use a lifting aid or get help

GENERAL RECOMMENDATIONS

Work stations should have additional vertical and horizontal adjustability to place employees into a proper space relationship with the items to be worked on. Employees use repeated, extended and elevated reaches to access work areas and to perform many tasks. Frequent elevated and/or extended reaches present a hazard as extending the arm creates a weak position in terms of arm strength which is consistent with the development of acute shoulder, upper arm, and upper back muscle and tendon fatigue and injury such as strains, sprains, and tears. In addition to acute muscle and tendon fatigue and failure there can be chronic tendon wear and tear, inflammation, and thickening which is consistent with the development of UECTDs such as bursitis, tendinitis, and rotator cuff injuries. Adjustability should be provided in the work stations such that the distance employees must reach to perform tasks can be reduced to ergonomically desirable distances. Generally, reaches should be limited to no more than 15 to 16 inches horizontally and work should be performed from about waist to shoulder height vertically.

Employees using a work stand to hold hog heads while removing the tongue routinely deviate their wrists and abduct their elbows out away from their bodies because the work stand from which cuts are performed is not adjustable. It is too high for most employees which forces them to assume awkward body postures to perform the task. This stresses the hands and shoulder causing repetitive injuries to those entities. A fully adjustable work stand should be provided which can be adjusted vertically and provides a tilt option such that employees of differing stature can make adjustments to minimize the use of awkward postures. Employees use repeated, extended and elevated reaches to place and retrieve bow knives, used in the loin pull area, into and from a heated trough. Redesigning the heated wash of the loin pull to be similar to the one used for the rib pull will reduce the reaches and the hazard of the task.

Employees perform frequent lifts and torso flexions with the arms extended in front of the body to load boxes of inedibles, and to stack loaded boxes of edible and inedible meat onto pallets laying on the ground. Even when there is no load or only a light load lifted flexing the torso creates a hidden lifting task with the weight of the entire upper body requiring support. Increasing the flexion of the torso increases the compressive forces on the low back as muscle force must continually be increased to counteract the downward force created by the load lifted and the weight of the upper body. Compressive forces generated on the spine of the low back are increased as muscle force is increased, since the spine is the focal point for the antagonistic forces created by contraction of the back muscles and the downward pull of the load. Frequent torso flexions are consistent with the development of low back injuries such as muscle strain and disk herniation.

Work stations should be redesigned to eliminate torso flexions and reduce the frequency and intensity of lifts. Redesign the conveyor which brings meat to the packing and weighing stations such that the meat drops directly into the box on the scale. This will eliminate the need to repeatedly lift quantities of meat from collection areas to the scale. If some sort of catch area is needed have the conveyor load directly to a box on a lower roller conveyor and when it is full replace it with another empty box while the full box is being weighed. Provide a tub dumper when bulk meat is transported in a tub. This will permit filling the boxes using a push and slide technique instead of repeatedly lifting materials from the tub to the box. Provide palletizers to all stackers such that all stacking to pallets can be performed at the ergonomically desirable level of about waist height.

There is frequent lifting, twisting, and throwing of bellies to elevated and distant sorting locations. Repeatedly twisting the torso during lifting operations increases the risk of low back injury significantly as it creates non symmetrical stress on the musculoskeletal system requiring smaller groups of muscles to exert force across a less structurally sound anatomical support mechanism. Frequent lifting with twisting is consistent with the development low back injuries. The use of repetitive throwing motions when combined with awkward hand and arm postures is consistent with the development of UECTDs such as tendinitis, tennis elbow (lateral epicondylitis) or golfers elbow (medial epicondylitis). Redesign of the workstation so employees can slide and push bellies to the appropriate sort area will reduce the number and severity of needed lifts. Have the conveyor bring the raw material to an elevated platform which has chutes such that sorters can push the appropriate belly to the chute opening and gravity will pull it to the collection area.

This tape shows employees shaving the carcass with knives or homemade razor devices. There is no mention of this procedure in reviewed descriptions of the slaughter and processing of hogs. Reviewed articles state simply that the hogs are soaked, washed, and singed to remove hair. This technique should be investigated to eliminate the shaving step or the current procedure should be improved to minimize the amount of shaving which is necessary.

Employees have extended periods of standing which creates static loading on the muscles of the back and legs. This is consistent with the development of musculoskeletal injury and generalized fatigue and can lead to venous pooling of blood in the legs which is consistent with increased fluid pressure in the legs and the development of varicose veins. In addition, the use of metal grating as the standing surface creates an additional contact trauma to the bottoms of the feet as the metal of the grate acts like a knife edge intensifying the force applied to the foot sole. This is consistent with the development of pain and fatigue in the feet and legs. Where employees are required to stand for long periods of time provide anti-fatigue mats, metal grates with larger flatter surface areas, and/or shoes with well cushioned insoles.

Employees use straight handled in-line style tools such as knives and shavers to perform many tasks. Use of this handle design requires employees to deviate the wrist while performing tasks which require forceful finger actions. The use of finger force while the wrist is in a deviated posture is consistent with the development of UECTDs such as tendinitis and carpal tunnel syndrome. Tools which have a bent handle such that the task can be completed while the wrist is maintained in an ergonomically neutral posture need to be developed.

It appears that employees must exert considerable finger force on the handles of the tools such as split saws and loin pull knives. Fatigue in this case can be exacerbated by the use of cotton gloves in conjunction with a slick tool handle or by the configuration of the handle which requires additional force to prevent slippage. Increasing the necessary finger force increases the risk for development of UECTDs such as tendinitis and carpal tunnel syndrome. When gloves are used make sure they fit properly and do not decrease tactile sensitivity. Gloves should be made of a material which increases the coefficient of friction between the hand and the load surface. This will reduce the hand and finger force required to perform a particular repetitive task. Providing vibration dampening material for the tool handle which also increase the coefficient of friction between the hand and tool will reduce the necessary grip force. The shape of the pull knife handle should be modified to give employees a hand-handle coupling which requires a minimum of finger force to maintain. Use of a stirrup type handle or one aligned 90 degrees from the current one will permit use of a power grip and allow employees to maintain a neutral wrist posture.

Many operations such as leaf lard pulling and gland pulling require employees to control and pull slippery entities. This requires use of significant finger force which is consistent with the development of tendinitis and muscle strain and fatigue. Employees should be provided with a glove which has a raspy surface such that pulling and separating can be performed with a minimum amount of finger force.

Employees performing head chiseling use forceful pulling motions on the chiseling rods to pull the meat away from the jaw bone. Forceful pulling stresses the musculoskeletal system of the fingers, upper arm and shoulder and is consistent with the development of acute injuries such as sprains and strains as well as chronic problems such as tendinitis, bursitis, and rotator cuff problems. Redesign of the rod device which is currently used to pull the meat from the jaw such that it has an oval configuration with two sharp edges which should permit the instrument to move through the meat with less effort since it will be cutting instead of ripping the meat from the bone.

Employees performing snout marking and head chiseling use the non-knife hand to clamp the head to the table and to hold the table mounted hook into the jaw. This requires prolonged static muscle contractions by the fingers which stresses the musculoskeletal system of the hand. This kind of stress is consistent with the development of UECTDs such as muscle strain, tendinitis and carpal tunnel syndrome. Provide the employee with a spike or other jig which will hold the head in a vertical configuration during trimming of the snout meat. In addition, provide a power activated mechanism for clamping the head to the table which will hold the head during chiseling. This will permit employees to use both hands for pulling during chiseling.

It appears that the pace of the conveyor in the gland pulling area is too fast. Employees routinely have to reach into the next work station because they have not performed the task when it was in their work area. Increasing the pace, in this area in particular and in the plant in general, will make this situation even worse. As employees are stressed trying to keep up with line production they tend to tense up which reduces blood flow to the musculoskeletal system and creates overall system fatigue. This tends to make employees more susceptible to localized fatigue, strains, sprains, and repetitive injuries. Create an off line accumulation area for employees to perform the task such that they can work at their own pace rather than being subjected to conveyor pacing. This would permit working at a slightly slower pace when the conveyor was running at full speed, but would also permit continuation of work when the conveyor was stopped which should produce the desired increase in production without pushing employees beyond their abilities.

Jobs should be classified as to the nature and extent of exertion and a rotation schedule should be created that allows for as much variation as possible in the distribution and frequency of musculoskeletal activity. Tasks such as shaving or snout markers and chiselers which involve repeated hand and finger tasks should be rotated with packaging and operation of the split saws which stress the back and shoulders. Rotation schemes which use different muscle groups provide needed rest while still allowing employees to produce.

Work-rest schedules should be developed and enforced. Generally, a minimum of a 15 minute rest break at least every two hours is required. Tasks which are very forceful or have high repetitions may need to have more frequent and longer periods of rest.

All employees need training in ergonomic principles so they can perform their jobs and utilize their tools and work stations in a safe manner. Training allows employees to recognize the early warning signs of a problem and to take action to prevent an injury where significant time may be lost due to surgery or incapacitation. Trained employees can also make a significant contribution in creating practical low cost solutions to ergonomic problems. They have extensive knowledge of the work situation and job performance requirements. When this is combined with an understanding of the basic principles for safe operation, remediation of the problem can often be attained. One such solution will more than repay the cost of initial training. Supervisors should be extensively trained and made to understand that safety and ergonomics problems are real and every bit as important to the bottom line as production considerations. Trained supervisors can also help recognize problems in their early stage and can act as a stimulant to reinforce proper, safe work techniques. No program will succeed unless management thoroughly understands its principals and openly supports its existence.

The specific task analysis of the video documentation collected at this Pork slaughter operation follows. Each task was studied to determine the ergonomic effects of several different factors. These factors are:

Frequency of the action or work cycle.
Awkward postures required to perform the task.
Forceful exertions required by the task.
Workplace conditions that may affect the hazard presented by a task.
Tools or Clothing used on the job which may affect the hazard presented by the task.

In some tasks all factors may be addressed and in others some factors may not be applicable. If a factor is not addressed in a particular task it was deemed to pose no problem in that particular task or it was not possible to make a determination from the submitted footage. In tasks where a hazard could be addressed under two factor areas it will only be listed in the factor deemed to be most relevant.

TASK # 1 Tape time- 00:00:00

SHAVING OPERATION - Hogs are shaved using knives and home made shaving devices similar to a paint scrapper. Shaving is performed as hogs pass by the station on an elevated conveyor line. Employees stand for the duration of the operation.

Frequency:

The rate of production as supplied by the compliance officer was 4300 hogs per day. This is about 540 hogs per hour. Further information indicates that production has been increased to 5300 hogs per day which would be a rate of about 660 hogs per hour.

Known Hazard

There are frequent extended and elevated reaches, wrist deviations while performing forceful finger activities, and the job entails long periods of standing. It is difficult to determine the absolute number of repetitions, or period of time that a posture can be maintained or an activity performed, which will cause an injury. But the risk of injury is definitely increased as static posture times or repetitions of a movement are increased. There are sufficient frequencies of stressors associated with this task to cause musculoskeletal injuries unless adequate engineering and administrative controls are implemented. Many of the engineering controls will be addressed in the following sections. Some administrative controls are mentioned below.

Known Control

Jobs should be classified as to the nature and extent of exertion and a rotation schedule should be created that allows for as much variation as possible in the distribution and frequency of musculoskeletal activity.
Work-rest schedules should be developed and enforced. Generally, a minimum of a 15 minute rest break at least every two hours is required.
Calculations indicate that employees are performing over 2000 repetitions per hour of arm activities caused by reaching and scraping actions. This figure is derived by observation that employees use at least 4 arm actions per hog during the shaving process and they average production of over 500 hogs per hour. Studies have shown that repetitions in excess of 1500 to 2000 per hour have been shown to cause tendon and sheath swelling. Generally, repetitions of movements should be kept below 1500 per hour especially for employees who show symptoms of repetitive motion injuries.
Singe and wash the hair off thus eliminating the need for shaving.

Awkward Postures:

Known Hazard

Employees use forceful finger actions while the wrist is in a deviated posture when shaving hog carcasses. The use of forceful finger actions with a deviated wrist is consistent with the development of UECTDs such as tendinitis, tenosynovitis, and carpal tunnel syndrome

Known Control

Educate employees on the basics of body biomechanics and the importance of maintaining the wrist in an ergonomically neutral position.
Provide bent handle knives which permit execution of the task while maintaining the hand in a neutral posture.
Provide materials for the hand to shaver or knife interface which will increase the coefficient of friction. Low coefficient of friction tool handles and gloves require employees to use additional finger force to maintain control of the tool. Increases in the force exerted by the fingers increases the risk of damage to the musculoskeletal system of the hand and arm. Anything which will increase the coefficient of friction between the hand and tool will reduce the chance of injury
Provide a shaver with a wrap around handle such that it can be maintained in the hand with only minimal finger pressure. This will provide mini rest pauses for the tendons and muscles of the hand.

Known Hazard

Employees use repeated, extended and elevated reaches by the left arm to perform cutting tasks. Frequent reaches present a hazard as extending the arm creates a weak position in terms of arm strength. Fully extending the arm is consistent with fatigue rates which are approximately 2 to 3 times faster than when the arm is bent and kept in close to the body. Frequent reaches are consistent with the development of acute shoulder, upper arm, and upper back muscle and tendon fatigue and injury such as strains, sprains, and tears. In addition to acute muscle and tendon fatigue and failure there can be chronic tendon wear and tear, inflammation, and thickening which is consistent with the development of UECTDs such as bursitis, tendinitis, and rotator cuff injuries.

Known Control

Move employees closer to the animal to be shaved and position them on height adjustable stands such that they can perform the task while maintaining reaches within ergonomically desirable ranges. Generally, employees should work within a range of approximately waist height to about shoulder height vertically and should limit reaches to 15 to 16 inches horizontally.

Workplace Conditions:

Known Hazard

Employees have extended periods of standing which creates static loading on the muscles of the back and legs. This is consistent with the development of musculoskeletal injury and generalized fatigue and can lead to venous pooling of blood in the legs which is consistent with increased fluid pressure in the legs and the development of varicose veins. In addition, the use of metal grating as the standing surface creates an additional contact trauma to the bottoms of the feet as the metal of the grate acts like a knife edge intensifying the force applied to the foot sole. This is consistent with the development of pain and fatigue in the feet and legs.

Known Control

Where employees are required to stand for long periods of time provide anti-fatigue mats, metal grates with larger flatter surface areas, and/or shoes with well cushioned insoles.

Tools and Clothing:

Known Hazard

Employees use straight handled in-line knives and shavers to perform this task. Use of this handle design requires employees to deviate the wrist while performing tasks which require forceful finger actions. The use of finger force while the wrist is in a deviated posture is consistent with the development of UECTDs such as tendinitis and carpal tunnel syndrome.

Known Control

Develop knives and shavers which have a bent handle such that the task can be completed while the wrist is maintained in an ergonomically neutral posture. The shavers used were described as home made by the compliance officer. The company should provide and improve this tool as it appears to require less deviation of the wrist while performing the task. The use of this tool should be expanded and switching from knife usage to shaver usage should be encouraged

TASK # 2 Tape time- 00:09:53

SPLIT SAW OPERATORS - Employees use large circular saws to cut hog carcasses in two. Hogs are hung by the hind leg and the cut is performed between the hind leg, down the spine, and to the neck. Employees stand for the entire operations.

Frequency:

The rate calculated from the video segment submitted for analysis is approximately 3 cuts per minute.

Known Hazard

There are frequent elevated and extended reaches, and the job entails long periods of standing. It is difficult to determine the absolute number of repetitions, or period of time that a posture can be maintained or an activity performed, which will cause an injury. But the risk of injury is definitely increased as static posture times or repetitions of a movement are increased. There are sufficient frequencies of stressors associated with this task to cause musculoskeletal injuries unless adequate engineering and administrative controls are implemented. Many of the engineering controls will be addressed in the following sections. Some administrative controls are mentioned below.

Known Control

Jobs should be classified as to the nature and extent of exertion and a rotation schedule should be created that allows for as much variation as possible in the distribution and frequency of musculoskeletal activity.
Work-rest schedules should be developed and enforced. Generally, a minimum of a 15 minute rest break at least every two hours is required.

Awkward Postures:

Known Hazard

Employees use repeated, extended and elevated reaches by the left arm to perform cutting tasks. Frequent reaches present a hazard as extending the arm creates a weak position in terms of arm strength. Fully extending the arm is consistent with fatigue rates which are approximately 2 to 3 times faster than when the arm is bent and kept in close to the body. Frequent reaches are consistent with the development of acute shoulder, upper arm, and upper back muscle and tendon fatigue and injury such as strains, sprains, and tears. In addition to acute muscle and tendon fatigue and failure there can be chronic tendon wear and tear, inflammation, and thickening which is consistent with the development of UECTDs such as bursitis, tendinitis, and rotator cuff injuries.

Known Control

Reduce the distance employees must reach to perform cutting tasks by redesign of the saw. Bend the forward handle back towards the employees so they do not need to reach so far forward to grasp the handle. Generally, reaches should be limited to no more than 15 to 16 inches.
Elevate employees slightly so they do not need to reach above about shoulder height to perform the task. Employees should be able to perform the task while keeping their hands below shoulder height and while maintaining their torsos in a vertical posture. Providing adjustable platforms so employees can raise or lower themselves for proper positioning will reduce the chance of torso flexion or elevated reaches.

Where employees are required to stand for long periods of time provide anti-fatigue mats, metal grates with larger flatter surface areas, and/or shoes with well cushioned insoles.
Supply sit/stand stools to employees so they can adjust the positions which they work to minimize the amount of loading on any one muscle group.

Tools and Clothing:

Known Hazard

It appears that employees must exert considerable finger force on the handles of the saw to maintain adequate control. Employees appear to be flexing and stretching their fingers when not performing the cuts as if they are extremely fatigued. Fatigue in this case can be exacerbated by the use of cotton gloves on a slick metal tool handle. The use of slick gloves on metal tool handles requires the use of increased finger force to maintain adequate control because of loss of tactile sensation and to overcome the resistance of the gloves. Increasing the necessary finger increase the risk for development of UECTDs such as tendinitis and carpal tunnel syndrome.

Known Control

Make sure gloves fit properly and do not decrease tactile sensitivity. Gloves should be made of a material which increases the coefficient of friction between the hand and the load surface. This will reduce the hand and finger force required to perform a particular repetitive task.
Provide vibration dampening material for the tool handle that will also increase the coefficient of friction thus decreasing the grip force required to control the tool.

TASK # 3 Tape time- 00:13:32

LEAF LARD PULLER - There are basically three jobs shown on this segment. The first employee uses some kind of a tool to remove the fat layer from the rib cage, the second grabs the loosened slab and pulls it free of the rib cage, and the third appears to use a whizzard knife to remove any remaining pieces of fat. Carcasses are presented to all positions by means of an overhead conveyor running in front of the employees. Removed fat is tossed behind the employee and all employees stand for the duration of the task.

Frequency:

The rate of the task was calculated from the video segment submitted for two separate employees and is approximately 8 and 10 chunks of fat pulled from the rib cage per minute.

Known Hazard

There are frequent elevated reaches, forceful finger exertions with wrist deviation, and the job entails long periods of standing. It is difficult to determine the absolute number of repetitions, or period of time that a posture can be maintained or an activity performed, which will cause an injury. But the risk of injury is definitely increased as static posture times or repetitions of a movement are increased. There are sufficient frequencies of stressors associated with this task to cause musculoskeletal injuries unless adequate engineering and administrative controls are implemented. Many of the engineering controls will be addressed in the following sections. Some administrative controls are mentioned below.

Known Control

Jobs should be classified as to the nature and extent of exertion and a rotation schedule should be created that allows for as much variation as possible in the distribution and frequency of musculoskeletal activity.
Work-rest schedules should be developed and enforced. Generally, a minimum of a 15 minute rest break at least every two hours is required.

Known Hazard

The frequency of lifts in this operation is critical since this task is in essence a lifting task. The maximum number of lifts per minute which can be performed on an 8 hour basis is 15. Compliance officer supplied data states that the line speed has been increased by almost 20% since the taping was performed. When the number of lifts approaches 15 the frequency factor of the NIOSH lifting guideline moves towards zero. As this factor becomes smaller the amount of weight that can safely be lifted rapidly approaches zero. This tape footage shows high enough lifting frequencies and restrictive enough access that increasing the line speed could reduce the allowable force generation to a point where pulling the lard exceeds the NIOSH lifting guidelines. Increasing the line speed while maintaining all other specifications of this task the same is consistent with the development of low back and shoulder pain and injury.

Known Control

Limit frequencies to a level where the overall force applied to pull the lard free from the carcass and to support the weight of the lard is less than the Action Limit calculated from the NIOSH lifting guidelines.

Awkward Postures:

Known Hazard

Employees use repeated elevated reaches to pull fat from the carcass and to use a tool to cut fat from the inside of the ribs. Frequent reaches, especially when exerting force in an upward pulling motion, presents a hazard as extending the arm creates a weak position in terms of arm strength. Fully extending the arm is consistent with fatigue rates which are approximately 2 to 3 times faster than when the arm is bent and kept in close to the body. Frequent reaches are consistent with the development of acute shoulder, upper arm, and upper back muscle and tendon fatigue and injury such as strains, sprains, and tears. In addition to acute muscle and tendon fatigue and failure there can be chronic tendon wear and tear, inflammation, and thickening which is consistent with the development of UECTDs such as bursitis, tendinitis, and rotator cuff injuries.

Known Control

Elevate employees slightly so they do not need to reach above about shoulder height to finish this task. Employees should be able to perform the task while keeping their hands below shoulder height and while maintaining their torsos in a vertical posture. Providing adjustable platforms so employees can raise or lower themselves for proper positioning will reduce the chance of torso flexion or elevated reaches. Taller employees depicted on the tape do not seem to need to reach above shoulder height to perform the task since they start pulling with their hands in a lower position with respect to their bodies.
Educate the employee on the basics of body biomechanics and the importance of maintaining the hand between about waist height and shoulder height. Employees should receive adequate training to correctly position adjustable work stations for safe operation.

Known Hazard

Employees use repeated finger force often with the wrist in a deviated posture to pull fat and to hold and activate powered trimming tools. The use of repeated finger force especially when the wrist is in a deviated posture is consistent with the development of UECTDs such as tendinitis and carpal tunnel syndrome.

Known Control

Educate the employee on the basics of body biomechanics and the importance of maintaining the wrist in an ergonomically neutral position.
Provide adjustable work platforms such that employees can perform the task while maintaining the wrist in neutral posture. Most employees deviate the wrist when using the trimming tool in an elevated position. Allowing employees to adjust the height of their stations will permit performance of the task with a minimum of wrist deviation.
Provide employees with a glove which has a raspy surface such that fat can be pulled with the minimum amount finger force exerted. Wrap the handles of tools with a material which has a high coefficient of friction. Both of these modifications will reduce the amount of required finger force exertion which reduces the hazard of finger intensive tasks.

Forceful Exertions:

Lifting calculations were performed on work tasks depicted on this video segment. The action limit (AL) for a frequency of 8 pulls per minute is about 12 pounds and for 10 lifts is about 9 pounds. Since weights and force were not documented a more thorough analysis was not performed. As was noted in the frequency section increasing the frequency of pulls could definitely reduce the AL and maximum permissible limit (MPL) to a level where this operation would be in violation of the NIOSH lifting guidelines. Frequencies should not be dramatically increased unless substantive changes are made to the work station.

Workplace Conditions:

Known Hazard

Employees have extended periods of standing which creates static loading on the muscles of the back and legs. This is consistent with the development of musculoskeletal injury and generalized fatigue and can lead to venous pooling of blood in the legs which is consistent with increased fluid pressure in the legs and the development of varicose veins. In addition, the use of metal grating as the standing surface creates an additional contact trauma to the bottoms of the feet as the metal of the grate acts like a knife edge intensifying the force applied to the foot sole. This is consistent with the development of pain and fatigue in the feet and legs.

Known Control

Where employees are required to stand for long periods of time provide anti-fatigue mats, metal grates with larger flatter surface areas, and/or shoes with well cushioned insoles.

TASK # 4 Tape time- 00:17:38

TONGUE REMOVERS - Employees remove the tongue from hog heads. The head is cut away from the body and placed on a stand from which the cuts are performed. The tongue meat is thrown into a bin and the head is thrown on a conveyor for further processing. Employees stand for the entire operation

Frequency:

It was not possible to accurately determine the frequency from the submitted video tape.

Known Hazard

There are frequent finger activations with wrist deviation, elbow abductions, and the job entails long periods of standing. It is difficult to determine the absolute number of repetitions, or period of time that a posture can be maintained or an activity performed, which will cause an injury. But the risk of injury is definitely increased as static posture times or repetitions of a movement are increased. There are sufficient frequencies of stressors associated with this task to cause musculoskeletal injuries unless adequate engineering and administrative controls are implemented. Many of the engineering controls will be addressed in the following sections. Some administrative controls are mentioned below.

Known Control

Jobs should be classified as to the nature and extent of exertion and a rotation schedule should be created that allows for as much variation as possible in the distribution and frequency of musculoskeletal activity.
Work-rest schedules should be developed and enforced. Generally, a minimum of a 15 minute rest break at least every two hours is required.

Where employees are required to stand for long periods of time provide anti-fatigue mats and/or shoes with well cushioned insteps and insoles.
Supply sit/stand stools to employees so they can adjust the positions which they work to minimize the amount of loading on any one muscle group.
Provide foot rests 4 to 6 inches above the floor allowing employees to rest one leg while standing. Foot rests are believed to alleviate back stress as well as minimize foot fatigue.

Known Hazard

Employees repeatedly deviate their wrists and abduct their elbows out away from their bodies because the work stand from which cuts are performed is not adjustable. It sits too high for most of the employees which forces them to use awkward body postures to perform the task. Using deviated wrist postures while performing tasks such as cutting which require frequent finger activations is consistent with the development of UECTDs such as tendinitis and carpal tunnel syndrome. Repeatedly abducting the elbow away from the body stresses the shoulder which is consistent with the development of UECTDs such as tendinitis, bursitis, and rotator cuff injuries.

Known Control

Provide a fully adjustable work stand to perform cuts off of. The stand should be adjustable vertically and should provide a tilt option such that employees of differing stature can adjust it to minimize the use of awkward postures. Ideally, employees should be able to adjust their stands such that they can perform most cuts while maintaining a neutral wrist posture and while keeping their elbows in close to the body.

Tools and Clothing:

Known Hazard

The knives in use by the employees have a straight in-line orientation which forces most employees to deviate their wrist while performing the necessary cuts. Deviation of the wrist while exerting finger force to hold the knife is consistent with the development of UECTDs such as tendinitis and carpal tunnel syndrome.

Known Control

Design and develop bent handle knives for individual tasks such that they can be performed while keeping the wrist in a neutral posture. The bend should be placed in the handle of the knife instead of in the wrist of the employee.

TASK # 5 Tape time- 00:22:18

PULL GLANDS - Employees pull glands from the viscera as it passes before them on a conveyor. They pull the glands by grasping them with one hand and holding the viscera with the other. Employees stand throughout the entire operation.

Frequency:

The rate calculated from the video segment submitted for analysis is approximately 9 glands pulled per minute.

Known Hazard

There are frequent forceful finger activations, forceful pulls, and the job entails long periods of standing. It is difficult to determine the absolute number of repetitions, or period of time that a posture can be maintained or an activity performed, which will cause an injury. But the risk of injury is definitely increased as static posture times or repetitions of a movement are increased. There are sufficient frequencies of stressors associated with the task to cause musculoskeletal injuries unless adequate engineering and administrative controls are implemented. Many of the engineering controls will be addressed in the following sections. Some administrative controls are mentioned below.

Known Control

Jobs should be classified as to the nature and extent of exertion and a rotation schedule should be created that allows for as much variation as possible in the distribution and frequency of musculoskeletal activity.
Work-rest schedules should be developed and enforced. Generally, a minimum of a 15 minute rest break at least every two hours is required.

Forceful Exertions:

Known Hazard

Employees use repetitive forceful finger exertions and forceful pulling actions to separate the glands from the rest of the viscera pile. The use of repetitive finger exertions is consistent with the development of UECTDs such as finger, arm, and shoulder fatigue and pain as well as tendon fatigue and swelling leading to tendinitis, tenosynovitis, and possibly carpal tunnel syndrome.

Known Control

Jobs should be classified as to the nature and extent of exertion and a rotation schedule should be created that allows for as much variation as possible in the distribution and frequency of musculoskeletal activity.
Work-rest schedules should be developed and enforced. Generally, a minimum of a 15 minute rest break at least every two hours is required. Employees which show signs of injury may need to be provided rest on a more frequent basis.
Provide employees with a glove which has a raspy surface such that the gland can be grasped, held, and pulled with a minimum of finger force. Gloves should fit correctly and provide a minimum of resistance to finger movement.

Workplace Conditions:

Known Hazard

It appears that the pace of the conveyor is too fast. Employees routinely have to reach into the next work station because they have not performed the task as it was in their work area. Increasing the pace will make this situation even worse. As employees are stressed trying to keep up with line production they tend to tense up which reduces blood flow throughout the musculoskeletal system and creates overall fatigue. This tends to make employees more susceptible to localized fatigue, strains, sprains, and repetitive injuries.

Known Control

Create an off line accumulation area where employees perform the task such that they can work at their own pace rather than being subjected to conveyor pacing. This will permit working at a little slower pace when the conveyor was running at full speed, but would also permit continuation of work when the conveyor was stopped.

Known Hazard

Employees have extended periods of standing which creates static loading on the muscles of the back and legs. This is consistent with the development of musculoskeletal injury and generalized fatigue. In addition this can lead to venous pooling of blood in the legs which is consistent with increased fluid pressure in the legs and the development of varicose veins.

Known Control

Where employees are required to stand for long periods of time provide anti-fatigue mats and/or shoes with well cushioned insteps and insoles.
Supply sit/stand stools to employees so they can adjust the positions which they work to minimize the amount of loading on any one muscle group.
Provide foot rests 4 to 6 inches above the floor allowing employees to rest one leg while standing. Foot rests are believed to alleviate back stress as well as minimize foot fatigue.

TASK # 6 Tape time- 00:27:35

SNOUT MARKER AND HEAD CHISELERS - Snout markers cut and peel the meat away from the snout of a hog skull. Chiselers use a metal rod in a prying motion to pull the meat away from the jaw bone. Heads are brought to employees by sliding them on a table, first to the marker and then to the chiseler.

Frequency:

The rate calculated from the video segment submitted for analysis is approximately 180 heads processed per hour for a marker/chiseler team.

Known Hazard

There are frequent finger actions performed with a deviated wrist, forceful pulling motions, forceful static arm postures, and the job entails long periods of standing. It is difficult to determine the absolute number of repetitions, or period of time that a posture can be maintained or an activity performed, which will cause an injury. But the risk of injury is definitely increased as static posture times or repetitions of a movement are increased. There are sufficient frequencies of stressors associated with this task to cause musculoskeletal injuries unless adequate engineering and administrative controls are implemented. Many of the engineering controls will be addressed in the following sections. Some administrative controls are mentioned below.

Known Control

Jobs should be classified as to the nature and extent of exertion and a rotation schedule should be created that allows for as much variation as possible in the distribution and frequency of musculoskeletal activity. Chiseler and marker jobs could be rotated frequently since both have the potential to utilize essentially different muscles.
Work-rest schedules should be developed and enforced. Generally, a minimum of a 15 minute rest break at least every two hours is required.

Awkward Postures:

Known Hazard

Employees use frequent finger actions with a deviated wrist to perform many of the cuts while removing meat from the hog snout. The use of repeated finger actions while the wrist is in a deviated posture is consistent with the development of UECTDs such as tendinitis and carpal tunnel syndrome.

Known Control

Place the head on a spike or other jig which will hold it in a vertical configuration. Then provide an ergonomically designed knife which will allow the employee to perform all of the necessary cuts while keeping the wrist in an ergonomically neutral posture.

Forceful Exertions:

Known Hazard

The employee uses the non-knife hand to clamp the head to the table and to secure the table mounted hook into the jaw. This requires prolonged static muscle contractions by the fingers which stresses the musculoskeletal system of the hand. This kind of stress is consistent with the development of UECTDs such as tendinitis and carpal tunnel syndrome.

Known Control

Provide the employee with a spike or other jig which will hold the head in a vertical configuration during trimming of the snout meat.
Provide a power activated mechanism for the table mounted hook which holds the head during chiseling. The mechanism should be foot activated which will permit employees to use both hands during chiseling.

Known Hazard

Employees perform forceful pulling motions on the chiseling rods to pull the meat away from the jaw bone. Forceful pulling stresses the musculoskeletal system of the fingers, upper arm and shoulder and is consistent with the development of acute injuries such as sprains and strains as well as chronic problems such as tendinitis, bursitis, and rotator cuff problems.

Known Control

Redesign the rod device which is currently used to pull the meat from the jaw such that it is in an oval configuration with two sharp edges. This should permit the instrument to move through the meat with less effort since it will be cutting instead of ripping the meat from the bone
Provide a power activated mechanism for the table mounted hook which holds the head during chiseling. The mechanism should be foot activated which will permit employees to use both hands during chiseling or allow them to alternate hands.

TASK # 7 Tape time- 00:31:41

CHEEKER - Employees use a knife to trim cheek meat from hog heads. The work is performed on a table where heads slide to employees. Employees stand during the duration of the task.

Frequency:

The rate calculated from the video segment submitted for analysis is approximately 3 heads processed per minute.

Known Hazard

There are frequent finger force activations with a deviated wrist and rotation of the forearm. Additionally, the job entails long periods of standing. It is difficult to determine the absolute number of repetitions, or period of time that a posture can be maintained or an activity performed, which will cause an injury. But the risk of injury is definitely increased as static posture times or repetitions of a movement are increased. There are sufficient frequencies of hand related stressors associated with this task to cause musculoskeletal injuries unless adequate engineering and administrative controls are implemented. Many of the engineering controls will be addressed in the following sections. Some administrative controls are mentioned below.

Known Control

Jobs should be classified as to the nature and extent of exertion and a rotation schedule should be created that allows for as much variation as possible in the distribution and frequency of musculoskeletal activity.
Work-rest schedules should be developed and enforced. Generally, a minimum of a 15 minute rest break at least every two hours is required.

Awkward Postures:

Known Hazard

Employees use repeated forceful finger actions with the wrist in a deviated posture. In addition, employees often rotate the forearm while performing the cuts. Deviation of the wrist is caused by the hog head laying flat on the work surface during the cutting process and forearm rotations are required to scoop the meat for the skull cavity. Repeated finger activations with the wrist in deviated postures is consistent with the development of UECTDs such as tendinitis and carpal tunnel syndrome. Rotation of the forearm with the previously mentioned finger and hand postures and actions is consistent with the development of medial epicondylitis (golfer's elbow).

Known Control

Develop a spike or jig which will hold the head in a vertical configuration. When combined with the use of an ergonomically designed knife this jig should provide a work station which permits employees to accomplish this task while maintaining the wrist in an ergonomically neutral posture.
Educate employees on the basics of body biomechanics and the importance of maintaining the wrist in an ergonomically neutral position.
Develop a loop whizzard knife which can scoop and cut the meat from this area while the wrist is maintained in an ergonomically neutral posture.

Forceful Exertions:

Known Hazard

The employees must work with the head bent forward at most times to view the heads which are worked on at table height. Working with the head bent forward is considered a "hidden lifting task," since the muscles in the back of the neck must lift or hold up the weight of the head, which is approximately 15 pounds. The farther the head is bent forward, the greater the strain. If the head is held in this position for a long period of time, the tensed, tightened neck and shoulder muscles can obstruct the blood flow in the area. This can cause the muscles to fatigue rapidly, to work less efficiently, and to become strained and sore. Eye fatigue is also not uncommon when working in this position, because the blood supply to the eyes can be obstructed or reduced by the tensed, tightened muscles. The stress of this position is increased when the torso is flexed and/or the arms are extended in front of the body. Tensed, tightened, and fatigued muscles in the shoulder and neck areas are consistent with the development of UECTDs such as muscle and eye strain, median nerve compression (often associated with carpal tunnel syndrome), headache and back problems.

Known Control

Develop a spike or jig which is height adjustable and will hold the head in a vertical configuration. When combined with the use of an ergonomically designed knife this jig should provide a work station which permits employees to accomplish this task while maintaining the wrist in an ergonomically neutral posture and will permit working without bending the head forward past recommended limits. Generally, the head should be tilted forward no more than 15 degrees from vertical and the employee should be able to view work items while looking along a horizontal plane or just slightly below horizontal

TASK # 8 Tape time- 00:34:20

PULL LOINS & PULL RIBS - Both of these tasks are essentially the same and will be considered together. Employees cut the loins or ribs away from the fat using two specialty designed bow knives. Meat is presented to employees on a conveyor which runs directly in front of them. Employees perform the cuts and throw or push the good meat to another conveyor while letting the fatty portion continue down the conveyor.

Frequency:

The rate calculated from the video segment submitted for analysis is approximately is highly variable depending on the position on the line but appears to be about 10 cuts per minute for loin pulling and 9 cuts per minute for rib pulling.

Known Hazard

There are frequent finger activations with wrist deviations, elevated reaches, and the job entails long periods of standing. It is difficult to determine the absolute number of repetitions, or period of time that a posture can be maintained or an activity performed, which will cause an injury. But the risk of injury is definitely increased as static posture times or repetitions of a movement are increased. There are sufficient frequencies of stressful postures and motions to cause musculoskeletal injuries unless adequate engineering and administrative controls are implemented. Many of the engineering controls will be addressed in the following sections. Some administrative controls are mentioned below.

Known Control

Jobs should be classified as to the nature and extent of exertion and a rotation schedule should be created that allows for as much variation as possible in the distribution and frequency of musculoskeletal activity.
Work-rest schedules should be developed and enforced. Generally, a minimum of a 15 minute rest break at least every two hours is required.

Awkward Postures:

Known Hazard

Employees pulling loins perform frequent and forceful finger actions with the wrist in deviated postures to draw the bow knife through the meat. Using frequent forceful finger actions, especially with the wrists in a deviated posture is consistent with the development of UECTDs such as tendinitis or carpal tunnel syndrome.

Known Control

Redesign the handle of the current knife such that it can be used with the hand in a neutral wrist posture. Use of a stirrup type handle or one aligned 90 degrees from the current position will permit use of a power grip and allow employees to maintain a neutral wrist posture.
Educate the employee on the basics of body biomechanics and the importance of maintaining the wrist in an ergonomically neutral position.
Ensure that meat is not frozen such that finger, arm and shoulder force required to pull the knife can be kept to a minimum.

Known Hazard

Employees use repeated, extended and elevated reaches to place and retrieve items from the heated trough. Frequent reaches present a hazard as extending the arm creates a weak position in terms of arm strength. Fully extending the arm is consistent with fatigue rates which are approximately 2 to 3 times faster than when the arm is bent and kept in close to the body. Frequent reaches are consistent with the development of acute shoulder, upper arm, and upper back muscle and tendon fatigue and injury such as strains, sprains, and tears. In addition to acute muscle and tendon fatigue and failure there can be chronic tendon wear and tear, inflammation, and thickening from repeated use which is consistent with the development of UECTDs such as bursitis, tendinitis, and rotator cuff injuries.

Known Control

Redesign the heated wash of the loin pull to be similar to the one used for the rib pull. Repositioning the wash will eliminate the need for unsafe reaches in the vertical and horizontal plane. Reaches should be limited to 16 to 17 inches horizontally and not higher vertically than about shoulder height.

Where employees are required to stand for long periods of time provide anti-fatigue mats and/or shoes with well cushioned insteps and insoles.
Supply sit/stand stools to employees so they can adjust the positions which they work to minimize the amount of loading on any one muscle group.
Provide foot rests 4 to 6 inches above the floor allowing employees to rest one leg while standing. Foot rests are believed to alleviate back stress as well as minimize foot fatigue.

TASK # 9 Tape time- 00:44:20

GRADE AND TRIM BELLIES - Employees inspect, trim, and sort hog bellies as they are delivered to them from the end of a feed conveyor. Sorted bellies are thrown into different bins depending on their quality. Employees stand for the duration of the task.

Frequency:

The rate calculated from the video segment submitted for analysis is approximately 9 lifts of bellies per minute.

Known Hazard

There are frequent lifts and throws of materials to distant and elevated sorting positions, and the job entails long periods of standing. It is difficult to determine the absolute number of repetitions, or period of time that a posture can be maintained or an activity performed, which will cause an injury. But the risk of injury is definitely increased as static posture times or repetitions of a movement are increased. There are sufficient frequencies of stressors associated with this task to cause musculoskeletal injuries unless adequate engineering and administrative controls are implemented. Many of the engineering controls will be addressed in the following sections. Some administrative controls are mentioned below.

Known Control

Jobs should be classified as to the nature and extent of exertion and a rotation schedule should be created that allows for as much variation as possible in the distribution and frequency of musculoskeletal activity.
Work-rest schedules should be developed and enforced. Generally, a minimum of a 15 minute rest break at least every two hours is required.

Awkward Postures:

Known Hazard

There is frequent lifting, twisting, and throwing of bellies to elevated and distant sorting locations. Repeatedly twisting the torso during lifting operations increases the risk of low back injury significantly as it creates non symmetrical stress on the musculoskeletal system requiring smaller groups of muscles to exert force across a less structurally sound anatomical support mechanism. Frequent lifting with twisting is consistent with the development low back injuries. The use of repetitive throwing motions when combined with awkward hand and arm postures are consistent with the development of UECTDs such as tendinitis, tennis elbow (lateral epicondylitis) or golfers elbow (medial epicondylitis).

Known Control

Redesign the system so the employee can slide and push bellies to the appropriate sort area. Have the conveyor bring the raw material to an elevated platform which has chutes such that sorters can push the appropriate belly to the chute opening and gravity will pull it to the collections device.
Educate the employee on the basics of body biomechanics and the importance of maintaining the torso in an ergonomically neutral position free from twisting motions.
Move bins closer to employees and instruct them to walk to the bin and place the item in it rather than throwing the meat to the receptacle.

Forceful Exertions:

Known Hazard

A lifting analysis was performed on work tasks pictured on the submitted video documentation. The lifts were calculated as per the NIOSH lifting guidelines. The data used in the calculation is given in the following table and was determined from the submitted video tape and accompanying compliance data:

Lift number; Tape time; and description of lift	H	V	D	Fmax	F
#1; 00:44:20; Graders sorting hog bellies	14"	34"	20"	15	9

H = Horizontal distance load is held from body V = Vertical distance at the point of origin D = Travel distance from origin to destination F = Repetitions per minute Fmax = Constant given as per certain situations

The following formula was used to do the calculations. The formula is taken from the "NIOSH Work Practices Guide for Manual Lifting":

AL (lbs) = 90*(6/H)*(1-(0.01(|V-30|))*(0.7+3/D)*(1-F/Fmax)

The Action Limits (ALs) and Maximum Permissible Limits (MPLs) calculated using the NIOSH Work Practices Guide are as listed in the following table. The current load being lifted as determined by compliance officer supplied information is 12 to 20 pounds.

Lift number; Tape time	AL	MPL	WEIGHT LIFTED
#1; 00:44:20	12	36	12 to 20 pounds

The AL and MPL values calculated are based on the current ideal weight limit guidelines of 90 pounds and on ideal lifting conditions which include the following:

Smooth lifts.
Two handed symmetric lifts in the sagittal plane with no twisting.
Moderate width (30 inches or less).
Unrestricted lifting postures.
Good couplings (handles, shoes, floor surface).
Favorable ambient conditions.
Maximum allowable weight of 90 pounds.

Since the load lifted is generally above the AL and the lifts do not conform to ideal lifting conditions they should be considered hazardous. Continued lifting of items in this weight range without implementation of proper administrative controls is consistent with the development of low back injury.

Known Control

Redesign the system so the employee can slide and push bellies to the appropriate sort area. Have the conveyor bring the raw material to an elevated platform which has chutes such that sorters can push the appropriate belly to the chute opening and gravity will pull it to the collections device.
Anything that will reduce the H,V, or D distances will reduce the chance of injury.

Where employees are required to stand for long periods of time provide anti-fatigue mats and/or shoes with well cushioned insteps and insoles.
Supply sit/stand stools to employees so they can adjust the positions which they work to minimize the amount of loading on any one muscle group.
Provide foot rests 4 to 6 inches above the floor allowing employees to rest one leg while standing. Foot rests are believed to alleviate back stress as well as minimize foot fatigue.

Tools and Clothing:

Known Hazard

There appears to be a contact trauma to the inside of employees fingers from use of the meat hook. Forceful contact by the hook to the small muscles and nerves located on the inside of the fingers is consistent with the development of pain, blood restriction, and damage to the affected entities.

Known Control

Redesign the current hook such that the pressure and force is spread out over the entire handle and is not repeatedly exerted over the area contacted by the fingers. Use a design similar to a brass knuckle where employees slip their hands through a handle such that the pressure is on palm and the outside of the finger instead of the inside of the fingers.
Pad the metal hook where it passes next to the fingers to widen the contact area such that the pressure is spread out over a wider area.

TASK # 10 Tape time- 00:47:50

PACKAGING OF EDIBLES AND INEDIBLES - Employees pack boxes with edible and inedible meat products for shipment to other users. Meat items are supplied to employees from bulk tubs wheeled to the loading site or from a bulk tub fed by a conveyor. Employees reach in with their hands and grab meat for transfer or use pitch forks and scoop meat from the tubs to the packing boxes. Boxes are packed with 50 to 60 pounds of meat products. After meat is boxed it is transferred from a conveyor to a packing pallet. Employees stand during the entire operation.

Frequency:

The rate calculated from the video segment submitted for analysis appears to be approximately as follows:

EMPLOYEE & TAPE TIME	LIFTS/MIN	SEQUENCE TIME (min.)
Inedible filler with box on scale; 00:48:06	14	2.5
Inedible box stacker; 00:48:49	1	2.5
Edible box filler; 00:51:10	10	0.7
Edible box stacker; 00:53:28	4	1.3

Known Hazard

The frequency of lifts in this operation can become critical when the observed number of lifts per minute approaches the maximum allowed for that particular posture and time frame. When the number of lifts approaches the maximum for frequency and posture, the NIOSH lifting guidelines move towards zero. As this factor becomes smaller the amount of weight that can safely be lifted rapidly approaches zero. This tape footage shows some high lifting frequencies which can severely reduce the weight that can be safely lifted. Continued lifting with the documented frequencies and weights is consistent with the development of low back pain and injury.

Known Control

See the accompanying information in the "Forceful Exertions Section". Where the AL and/or MPL is exceeded work station redesign or work practice modification needs to be instituted.

Known Hazard

There are frequent lifts, torso flexions, and the job entails long periods of standing. It is difficult to determine the absolute number of repetitions, or period of time that a posture can be maintained or an activity performed, which will cause an injury. But the risk of injury is definitely increased as static posture times or repetitions of a movement are increased. There are sufficient frequencies of stressors to cause musculoskeletal injuries unless adequate engineering and administrative controls are implemented. Many of the engineering controls will be addressed in the following sections. Some administrative controls are mentioned below.

Known Control

Jobs should be classified as to the nature and extent of exertion and a rotation schedule should be created that allows for as much variation as possible in the distribution and frequency of musculoskeletal activity.
Work-rest schedules should be developed and enforced. Generally, a minimum of a 15 minute rest break at least every two hours is required.

Awkward Postures:

Known Hazard

Employees perform frequent torso flexions with the arms extended in front of the body to load boxes of inedibles, and to stack loaded boxes onto pallets laying on the ground. Even when there is no load or only a light load lifted flexing the torso creates a hidden lifting task with the weight of the entire upper body requiring support. Increasing the flexion of the torso increases the compressive forces on the low back as muscle force must continually be increased to counteract the downward force created by the load lifted and the weight of the upper body. Compressive forces generated on the spine of the low back are increased as muscle force is increased, since the spine is the focal point for the antagonistic forces created by contraction of the back muscles and the downward pull of the load. Frequent torso flexions are consistent with the development of low back injuries such as muscle strain and disk herniation. Holding a load while flexing the torso significantly increases low back stress and increasing the distance the load is held from the body directly increases the hazard of low back injury.

Known Control

Educate the employee on the basics of body biomechanics and the importance of maintaining the back in an ergonomically neutral position. Generally, the torso should not be flexed more than 6 to 10 from vertical.
When meat comes to stations on a conveyor redesign the conveyor such that the meat drops directly into the box on the scale. This will eliminate the need to repeatedly lift quantities of meat from a tub to the scale. If some sort of catch area is needed have the conveyor load directly to a box on a conveyor and when it is full replace it with another box. Move the original to the scale, bring it to weight, and then move it to the next station. As the new box fills repeat the process.
Provide palletizers to employees such that the destination height of the pallet is always maintained at the ergonomically desirable level of about waist height.

Lift number; Tape time; and description of lift	H	V	D	Fmax	F
#1; 00:48:06; Lift from tub to box on scale	14"	30"	18"	15	14
#2; 00:48:49; Stack boxes of inedibles	22"	36"	25"	13.5	1
#3; 00:51:10; Load edibles with pitchfork	18"	20"	20"	15	10
#4; 00:53:28; Stack boxes of edibles	20"	34"	28"	13.5	4

Lift number; Tape time	AL	MPL	WEIGHT LIFTED (pounds)
#1; 00:48:06	2.3	7	about 5
#2; 00:48:49	17	52	50
#3; 00:51:10	7.5	23	about 15
#4; 00:53:28	15	44	60

The AL and MPL values calculated are based on the current ideal weight limit guidelines of 90 pounds and on ideal lifting conditions which include the following:

Smooth lifts.
Two handed symmetric lifts in the sagittal plane with no twisting.
Moderate width (30 inches or less).
Unrestricted lifting postures.
Good couplings (handles, shoes, floor surface).
Favorable ambient conditions.
Maximum allowable weight of 90 pounds.

Since the load lifted is above the MPL for some lifts and over the AL for all lifts and lifts do not conform to ideal lifting conditions they should be considered hazardous. Continued lifting, of items in this weight range, without implementation of administrative and engineering controls is consistent with the development of low back injury.

Known Control

Educate the employee on the basics of body biomechanics and the importance of maintaining the body in an ergonomically neutral position. Generally speaking the torso should not be bent forward more than 6 to 10 degrees from vertical and reaches should not exceed 16 to 17 inches.
Anything that will reduce the H,V, or D distances will reduce the chance of injury.
Provide a tub dumper for employees of the edibles line. This will permit filling the boxes using a push and slide technique instead of repeatedly lifting materials from the tub to the box.
When meat comes to stations on a conveyor redesign the conveyor such that the meat drops directly into the box on the scale. This will eliminate the need to repeatedly lift quantities of meat from a tub to the scale. If some sort of catch area is needed have the conveyor load directly to a box on a conveyor and when it is full replace it with another box. Move the original to the scale, bring it to weight, and then move it to the next station. As the new box fills repeat the process.
Provide palletizers to employees such that destination heights are always maintained at the ergonomically desirable level of about waist height.

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