Ergonomic Exposures And Controls: Chemical Bag Weighing And Stacking

DESCRIPTION OF WORK TASKS

Employees work on a bag filling line where a hopper fills heavy paper bags with a powdered chemical and the bags are automatically sewed shut. The bags then fall flat onto a continually operating conveyor and are transported towards a loading station. Employees grab the bags with their bare hands and pull the bag toward them to place onto a scale for weighing. The bag is then manually lifted and placed onto a pallet that is adjacent to the employee on the floor. The bags weigh 40 pounds, and the pallet is stacked six tiers high prior to being picked up by a fork truck. Employees sometimes stretch across the pallet to ‘throw’ the bags, and other employees walk around the pallet to place bags onto the farthest stack.

EXPOSURES

• Reaching far from the body while bearing relatively heavy weight.
• Torso flexion with twisting to lift and lower bags.
• Forceful pinch grips to pull bags toward the employee.
• Extended periods of standing, which creates static loading on the muscles of the back and legs.
• Dermal irritation from chemical and physical abrasion of the forearms and hands.
• Repeated lifting of weights approaching the 51-pound recommended maximum weight limit set by NIOSH.

CONTROLS

• Develop a trolley system that runs from the filling machine to the pallet. The bucket of the trolley should have one open side where the bag could be placed as it is filled from the hopper nozzle.
• When filled, the bag should be moved to the pallet, which would be located on a palletizer equipped with a rotating turntable.
• Inclusion of the scale into the trolley bucket system would reduce the number of lifts by half since the employee could weigh the bag while transporting it to the pallet.
• Using a palletizer and turntable would allow the employee to always deliver and maneuver the load at the ergonomically optimal level of waist height, which should reduce the hazard of the lifts.
• The trolley and basket system for transport would nearly eliminate the need for lifting and carrying bags using pinch grips.
• Any system that allows the employee to control and transport the bags without using pinch grips will reduce hazardous ergonomic exposures.
• Provide the employee with adjustable equipment so that they can load and unload items at the optimal work height of about waist level. Adjust-ability should be provided for the filling mechanism, scale, and pallets. Generally, torso flexion should be limited to 6 to 10 degrees. For these lifts, the load should be kept close to the body, lifted and lowered at about waist height.
• Instruct the employee on how to properly grip the bags while facing the load. Keep the horizontal distance between the bag and the body as low as possible, and avoid twisting at all times. Keeping the bag close to the body while turning the feet and not the torso will reduce the twisting hazard. Arranging the filling machine, scale and pallets in a row such that access is limited to one direction will help reduce the temptation to twist the torso during transport.
• Where employees are required to stand for long periods, provide anti-fatigue mats and/or shoes with well-cushioned insteps and insoles.
• Provide sit/stand stools to employees so they can adjust the positions in which they work. This will minimize the amount of loading on any one muscle group.
• Provide footrests 4 to 6 inches above the floor. These allow employees to rest one leg while standing. Footrests can alleviate back stress as well as minimize foot fatigue.

XL Environmental • Risk Control Division • 520 Eagleview Boulevard, PO Box 636, Exton, PA 19341 • Phone: 800-327-1414 • Fax: 610-458-7285 • xlenvironmental.com

XL Environmental is a division of XL Specialty Insurance Company.