Elements of Ergonomics Programs A Primer Based on Workplace Evaluations of Musculoskeletal Disorders

NIOSH was asked to conduct a health hazard evaluation at a plant that fabricates wheels for trucks and busses. Major plant processes involved forming steel stock into the rims and center cores of the wheels, welding them together, and finishing and painting the welded product which was then crated for shipment. One objective of the evaluation was to verify the company's concerns about musculoskeletal problems that seemed related to operations in assembly and disc forming work. NIOSH reviewed the company's OSHA log entries for injuries and illnesses for the past 2 years and found about half (291 of a total of 588 entries) were cases of strains and sprains, carpal tunnel syndrome, tendonitis, bursitis, and other musculoskeletal problems. The musculoskeletal injury rate for the plant was 26.1 injuries per 100 employees. This rate exceeded the expected rate of 10.6 injuries per 100 employees based on the Bureau of Labor Statistics' reports that were then available for the motor vehicle parts industry. Back injury (primarily low back strain) constituted the largest proportion of injuries in the strain and sprain category; the total plant rate for back disorders was 11.3 injuries per 100 workers per year which was 5 times the rate for the industrial workforce as a whole. The rate of back disorders was highest in the Assembly Department (23.7 injuries per 100 workers per year) followed by the Disc Forming Department (20.0 injuries per 100 workers per year). Consequently, job tasks in these two departments became the primary targets for analyzing and controlling risk factors (predominantly repeated, heavy lifting) that could account for the observed musculoskeletal problems [HETA 88-277-2069].