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Epidemiologic Notes and Reports Work-Related Injuries and Illnesses in an Automotive Parts Manufacturing Company -- Chicago

In 1985, 146 work-related injuries and illnesses occurred among the 349 full-time workers in an automoive parts manufacturing company in Chicago. The company's injury/illness rate of 41.8 cases per 100 full-time workers per year was more than four times greater than the 1985 industry average of 10.1 cases per 100 workers, as reported by the Bureau of Labor Statistics (BLS), for companies manufacturing motor vehicle parts (1).

In March 1986, the company requested that the Rush-Presbyterian-St. Luke's Occupational Health Centers in Chicago evaluate its 1985 injury experience. Examination of workers' compensation records, Occupational Safety and Health Administration (OSHA) records, medical reports, and insurance records showed high rates of musculoskeletal and dermatologic injuries, including sprains/strains (11.2 per 100 full-time workers), contusions (10.0), and cuts/lacerations (5.4). The most commonly affected body parts were the finger (10.3 per 100 full-time workers), back (6.3), and hand (4.6). The most prevalent nature-of-injury categories (e.g., sprains/strains, contusions, cuts/lacerations) were further evaluated for the most common sources (e.g., boxes, metal items, machines) and types (e.g., overexertion, being struck by an object) of injury. Fifty-four percent of sprains/strains were associated with boxes; 87%, with overexertion (i.e., excessive physical effort associated with the lifting, pushing, or pulling of an external object). Forty percent of contusions were associated with boxes; 46% resulted from having been struck by an object. Fifty-eight percent of cuts/lacerations were associated with contact with metal items.

In March 1986, simultaneous with the analysis of its 1985 injuries, the company modified its procedures for handling materials. These changes included 1) a decrease in the size of the boxes used to transport automotive parts, 2) a decrease in the average weight of the boxes from 50 to 25 pounds, and 3) the installation of manual conveyors and lift assists designed to decrease manual lifting requirements. The company also sponsored regular plant inspections, safety films, lectures, and various safety contests.

In April 1988, the company's 1986 injury experience was analyzed to evaluate the effectiveness of the interventions. From workers' compensation forms, OSHA records, and medical reports, 44 work-related injuries and illnesses were identified among the company's 321 full-time workers. Even though the populations in 1985 and 1986 were not fully independent, the injury/illness rate of 13.7 cases per 100 workers for 1986 represents a statistically significant decrease of 67% from the company's 1985 rate of 41.8 (chi-square test, p less than 0.05) (Table 1).

After intervention, sprains/strains decreased 80% to 2.2 injuries per 100 workers, contusions decreased 63% to 3.7, scratches/abrasions decreased 85% to 0.6, and other injuries (e.g., multiple injuries, inflamed joints, burns) decreased 58% to 3.4 (Table 1). Injures to the finger, back, hand, and other body parts (e.g., shoulders, arms, toes) also showed statistically significant declines (chi-square test, p less than 0.005) (Table 1). These analyses take into account the effect of multiple comparisons on the significance level.

The turnover rate for the company's workforce between 1985 and 1986 was 4%, and the composition of the workforce remained stable. Hourly workers accounted for 295 (85%) of the company's 349 full-time employees in 1985 and for 268 (83%) of 321 full-time workers in 1986. Age and sex distributions for the hourly workforce were comparable between 1985 and 1986. Machine operators and assemblers were the most frequently injured workers in both years, accounting for 42% and 25%, respectively, of the injuries in 1985, and for 57% and 16%, respectively, of the injuries in 1986.

Direct costs associated with the implementation of changes in the company's procedures for handling materials totaled $190,000; however, on its 1986 workers' compensation insurance premium, the company received a $100,000 rebate, which was attributed to an improvement in its safety record. Reported by: R Brewer, MD, D Oleske, PhD, J Hahn, MD, P Doan, M Leibold, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois. Div of Safety Research, National Institute for Occupational Safety and Health; Div of Injury Epidemiology and Control, Center for Environmental Health and Injury Control, CDC.

Editorial Note

Editorial Note: Workplace injury rates can be reduced by changing the procedures governing the handling of materials. This report describes the approach taken by an automotive parts manufacturing company in characterizing injuries related to materials handling, targeting interventions, and evaluating the impact of intervention measures.

Musculoskeletal injuries (sprains/strains; inflammation and irritation of joints; fractures and dislocations) and dermatologic injuries (contusions; cuts/lacerations; scratches/abrasions) are common, sometimes disabling, work-related health problems. According to data provided by the BLS, musculoskeletal injuries accounted for 57% and dermatologic injuries for 23% of the total occupational injuries and illnesses reported nationwide in 1985 (2). Sprains/strains accounted for 43%, and contusions accounted for 10% of the total (2).

Poorly designed procedures for handling materials are associated with an increased risk of both musculoskeletal and dermatologic injuries (3). The weight of the material being handled has been identified as the factor most associated with an increased risk of injury (4).

Given the relatively stable workforce of the Chicago automotive parts company, the decline in injury rates from 1985 to 1986, particularly for sprains/strains and for contusions, suggests that the changes in procedures for handling materials were effective. These changes are generally consistent with findings of previous epidemiologic and ergonomic studies that identified associations between injury rates and materials handling procedures (5,6). However, the declines may also reflect the effect of the workers' additional on-the-job experience.

The experience of this company illustrates the impact that changes in procedures for handling materials may have on the occurrence of work-related injuries. Ergonomic interventions, taking into account worker capabilities and limitations, were applied to specific tasks associated with the most frequent injuries. The company's rebate on its 1986 workers' compensation insurance premium helped to offset the initial expense associated with the implementation of changes in procedures for handling materials. Thus, the potential for substantial cost savings exists when effective injury-control programs are implemented in the workplace. Ergonomic interventions can also be applied to the control of injuries in other worksites. To measure the effectiveness of ergonomic interventions, the age, sex, job training, and job experience of the workforce should be identified both before and after intervention. Also, the extent and severity of the injuries should be measured before and after intervention measures. Ergonomic interventions should be applied separately from health education programs (e.g., safety films and lectures) if their individual effect on injury rates is to be evaluated. Broader application of both epidemiologic and ergonomic models to the planning and evaluation of injury-control programs should be encouraged to reduce the incidence and cost of work-related injuries.


  1. Bureau of Labor Statistics. Occupational injuries and illnesses in the United States by industry, 1986. Washington, DC: US Department of Labor, Bureau of Labor Statistics, 1988. (Bulletin no. 2308).

  2. Bureau of Labor Statistics. Supplementary Data System (machine-readable data files). Washington, DC: US Department of Labor, Bureau of Labor Statistics, 1985.

  3. NIOSH. Work practices guide for manual lifting. Cincinnati: US Department of Health and Human Services, Public Health Service, 1981:130; DHHS publication no. (NIOSH)81-122.

  4. NIOSH. Work practices guide for manual lifting. Cincinnati: US Department of Health and Human Services, Public Health Service, 1981:14; DHHS publication no. (NIOSH)81-122.

  5. Snook SH, Campanelli, RA, Hart JW. A study of three preventive approaches to low back injury. J Occup Med 1978;20:478-81.

  6. Klein BP, Jensen RC, Sanderson LM. Assessment of workers' compensation claims for back strains/sprains. J Occup Med 1984;26:443-8.

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