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Worker Health Study Summaries

Research on long-term exposure

Exposure to Polychlorinated Biphenyls and the Risk of Disease


Study Background

Polychlorinated Biphenyls (PCBs) are synthetically produced chemicals formerly used to manufacture electrical capacitors.

Increasing concerns about PCBs’ potential health and environmental effects led to a ban on PCB production and use in the U.S. in 1977.

The purpose of the NIOSH studies was to examine the long-term health risks to workers from PCB exposures.

Studies were undertaken examining causes of death among workers from three electrical-capacitor manufacturing plants located in Indiana, New York, and Massachusetts.

Study Results

Compared to the U.S. population, the overall number of deaths was not increased among workers at the study plants.

In the Indiana plant, the numbers of deaths from melanoma skin cancer) and brain cancer were higher than expected. We found deaths from brain cancer to be associated with PCB exposure.

In the New York and Massachusetts plants combined, deaths from myeloma (cancer of the bone marrow), and cancers of the liver, stomach in men, ovary and prostate were higher than expected among workers with greater cumulative PCB exposure.

A study of neurological diseases (amyotrophic lateral sclerosis [ALS], Parkinson's disease, and dementia) included everyone in the three plants who had worked 90 days or longer. Women in the study had excess deaths from ALS, compared to women in the U.S. population. Women with greater cumulative PCB exposure had more deaths from Parkinson's disease and dementia than women with lower cumulative PCB exposure.


From these studies, there is evidence that PCB exposure may be associated with some cancers and some neurological diseases.

Results were not entirely consistent across all three plants. This might be due to variations in exposure levels among the plants or due to other factors not measured.

Important: These studies evaluated workers as a group; therefore,we cannot predict the future health of any one individual.

Questions or Comments?

If you have any questions or comments, would like more information, or would like a copy of any of the four study reports (one study in Indiana, two studies in Massachusetts-New York, one study of all three plants):

Call our NIOSH toll-free 800 number: 800-356-4674 (800-35-NIOSH).

You may e-mail questions, comments, or suggestions to:

For other NIOSH publications write to

NIOSH Publications
4676 Columbia Parkway
Cincinnati, OH 45226-1996
Phone: 800-356-4674 (800-35-NIOSH)
Fax: 513-533-8573
Web site:

References - Published PCB Studies

Steenland K, Hein MJ, Cassinelli RT, et al. [2006]. Polychlorinated biphenyls and neurodegenerative disease mortality in an occupational cohort. Epidemiology 17(1):8-13.

Ruder AM, Hein MJ, Nilsen N, et al. [2006]. Mortality among workers exposed to polychlorinated biphenyls (PCBs) in an electrical capacitor manufacturing plant in Indiana: an update. Environ Health Perspectives 114(1): 18-23.

Prince MM, Ruder AM, Hein MJ, et al. [2006]. Mortality and exposure response among 14,458 electrical capacitor manufacturing workers exposed to polychlorinated biphenyls (PCBs). Environ Health Perspectives 11(10):1508-1514.

Prince MM, Hein MJ, Ruder AM, et al. [2006]. Update: cohort mortality study of workers highly exposed to polychlorinated biphenyls (PCBs) during the manufacture of electrical capacitors, 1940-1998. BMC Environmental Health, 5(13):1-10.

Additional Information about Cancer and Neurological Diseases

Polychlorinated Biphenyls (PCBs) may increase the risk for certain diseases. Below are agencies with their addresses, telephone numbers, and internet sites that may be helpful in answering any questions you may have regarding the cancers and neurological diseases mentioned in the studies.


The American Cancer Society is a national, non-profit agency devoted to assist and answer questions one may have regarding cancers.

American Cancer Society
2970 Clairmont Road, NE
Suite 840
Atlanta, Georgia 30329
Toll Free: 800-227-2345

The National Cancer Institute is a Federal agency for cancer research. They can answer questions you may have about cancer. They can also provide the names of doctors in your area who treat patients with cancer.

National Cancer Institute
Room 10A28
31 Center Drive, MSC 2580
Bethesda, Maryland 20892
Toll Free: 800-4-CANCER

Neurological Diseases

National Parkinson Foundation, Inc.
1501 N.W. 9th Avenue / Bob Hope Road
Miami, Florida 33136-1494
Telephone: 305-243-6666
Toll Free: 800-327-4545
Fax: 305-243-5595

National Parkinson Disease Association
135 Parkinson Avenue
Staten Island, New York 10305
Telephone: 718-981-8001
Toll Free: 800-223-2732
Fax: 718-981-4399

Alzheimer’s Association National Office
225 N. Michigan Ave., Fl. 17
Chicago, Illinois 60601
24/7 Helpline: 800-272-3900

The Amyotrophic Lateral Sclerosis (ALS) Association
27001 Agoura Road - Suite 150
Calabasas Hills, Califonia 91301
Telephone: 818-880-9007

Web Based Resources






Neurological Diseases


Alzheimer’s disease:

Parkinson’s disease:

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