1992
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.
STS
Workers exposed to dioxin had an increased chance of getting soft
tissue sarcoma (STS). This is a rare kind of cancer.
All Workers in the Study
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.
Injuries
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: 1-800-356-4674. Say you're calling
about the dioxin study.