Worker Health Study Summaries – TCDD (Dioxin)

Research on long-term exposure

TCDD (Dioxin) Manufacturers (1) (Dioxin Exposure)


Why the Study Was Done

The purpose of the study was to see if potential exposure to chemicals containing dioxin was related to increased death rates in workers compared to the general U.S. population.

The Study Group

The study group included 5,172 workers at 12 chemical plants. All had worked in departments where chemicals likely to contain dioxin were made.

What the Study Found

Our conclusions come from the whole study-all 5,172 workers at 12 plants. Workers in the study were exposed to many different chemicals at work. Dioxin was in some of them. Therefore, it’s hard for us to know for sure whether dioxin or other chemicals caused increased risks of disease.

All Cancers

We looked at the risk for all kinds of cancer considered together. Workers exposed to dioxin had a slightly greater risk of dying from cancer than the general public (230 deaths expected, 265 found). The extra cancers were mainly in the group of workers exposed to dioxin for more than 1 year (78 expected, 114 found). These workers were about 1 and a half times more likely to die of some kind of cancer than men in the general public. Workers exposed for less than 1 year had the same risk as the general public (47 expected, 48 found). Most of the cancer deaths were from lung cancer, but there were other kinds, too. It’s possible that smoking caused some of the increased lung cancer.

Soft Tissue Sarcoma (STS)

Workers exposed to dioxin had an increased chance of getting soft tissue sarcoma (STS). This is a rare kind of cancer.

We expected slightly more than 1 death from STS and found 4. This means workers were over 3 times more likely to get STS than men in the general public. The risk of getting STS was mainly seen in workers exposed to dioxin for over 1 year (1/3 expected, 3 found). These workers were over 9 times more likely to get STS. These are our best estimates of the risk, but it is difficult to interpret these results because of the small number of deaths involved. Even though the risk was high, very few workers will get STS because it is so rare.


Workers were about 1 and a quarter times more likely to die of injuries than men in the general public (83 expected, 106 found).

Putting the Risks in Perspective

To put these risks in perspective, we can compare them to the risk of getting lung cancer from cigarette smoking. Smokers are about 9 times more likely to die of lung cancer than nonsmokers.

Steps to Protect Your Health

Since smoking is a major cause of cancer, stopping smoking will help to protect your health. There are no specific medical tests for most of the excess cancers seen in this study. However, you may wish to ask your doctor’s advice on tests for colon cancer.

Any Questions?

If you have any questions about this study, call the NIOSH toll-free number: 800-356-4674. Say you’re calling about the dioxin study.

Additional Resources

Fingerhut M, Halperin W, Marlow D et al. (1991). Cancer mortality in workers exposed to 2,3,7,8-Tetrachlorodibenzo-p-dioxin. New England Journal of Medicine 324:212-218.

Steenland K, Piacitelli L, Deddens J et al. (1999). Cancer, heart disease, and diabetes in workers exposed to 2,3,7,8-Tetrachlorodibenzo-p-dioxin. Journal of the National Cancer Institute 91 (9): 779-786.

American Cancer Society. Taking Control- 10 steps to a healthier life and reduced cancer risk.85-5MM-Rev. 5/87-No.2019.05

Page last reviewed: April 8, 2020