Worker Health Study Summaries – Electrical Capacitor Manufacturing Workers

Research on long-term exposure

Electrical Capacitor Manufacturing Workers (Polychlorinated biphenyls (PCB’s))


Study Background

The National Institute for Occupational Safety and Health (NIOSH), in collaboration with the Indiana State Board of Health, concluded a mortality study of 3588 electrical capacitor manufacturing workers employed between January 1, 1957 and March 31, 1977 and exposed to polychlorinated biphenyls (PCB’s).

Study Results

A common finding in studies of this kind is that the workers studied usually exhibit lower overall death rates than the general population. This is called the “healthy worker effect” because workers generally have better health than the non-working population. In this study, NIOSH found out that there were fewer deaths than expected for heart disease, respiratory disease, diseases of the digestive system, and all forms of cancer combined.

The study did determine, however, that eight workers had died of malignant melanoma, a type of skin cancer, as opposed to the two that were expected. The study found no definite causative link between the disease and exposure to PCB’s or any other compound. The study’s final report states, “The possibility that these observations (more melanoma deaths than expected) resulted because of chance, bias, or confounding factors cannot be excluded as alternative explanations.”

Malignant Melanoma

The American Cancer Society reports the incidence of malignant melanoma in the general population of the United States is increasing. Some of the more common factors known to be associated with malignant melanoma are frequent sunburns early in life, overexposure to the sun, and the presence of certain types of moles. Persons with light complexions or a family history of melanoma are more susceptible to the disease.

Melanoma can be cured if it is found early and treated. The American Academy of Dermatology recommends a complete annual skin examination by a doctor. The American Cancer Society and the National Cancer Institute both recommend that a complete skin examination should be part of a routine physical examination. NIOSH also recommends periodic examination for malignant melanoma as stated in the study’s final report.

What to Do

You may obtain two pamphlets to give you more information regarding skin cancer.

  • “Why You Should Know About Melanoma.” It is from the American Cancer Society. It describes malignant melanoma, its detection, some of its causes, and its symptoms.
  • “What You Need To Know About Skin Cancer.” It is from the National Cancer Institute. It provides information about skin cancer in general.

If you are concerned about any health condition, it is always prudent to consult your physician or a medical specialist. Dermatologists are medical doctors who specialize in health care of the skin. If you wish to see a dermatologist, you can ask your doctor to refer you to one or you can call your local health department or medical society.

If you would like a copy of the NIOSH report, ask for code HETA 89-116-209 by writing to the:

The National Institute for Occupational Safety and Health
Hazard Evaluations and Technical Assistance Branch, R-9
4676 Columbia Parkway
Cincinnati, Ohio 45226-1998

If you have any questions after reading the report or need any further assistance, you may contact NIOSH directly at 800-356-4674. When writing or calling, refer to the “Bloomington Study.”


Sinks T, Smith A, Rinsky R et al. NIOSH Health Hazard Evaluation Report. HETA 89-116-209. January 1991.

“What You Need To Know About Skin Cancer”. National Cancer Institute. NIH Publication No. 90-1564.

“Why You Should Know About Melanoma”. American Cancer Society.

Page last reviewed: April 8, 2020