EPA: Dioxin May Cause Cancer in Humans

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May 16, 2001 (Washington) -- A draft report to the Environmental Protection Agency concludes that dioxin causes cancer not only in animals but possibly in people as well. The final review from a badly divided scientific advisory board is expected to be on EPA Administrator Christie Todd Whitman's desk by June 1.

That puts the ball in the Bush administration's court in terms of dealing with a long-recognized environmental hazard.

The majority of the 17-member board believes dioxin's link to human cancer is unresolved, but a vocal minority thinks just the opposite.

"It causes cancer in people, and it causes a lot of other neurological and reproductive effects. ... Dioxin is basically more hazardous than they thought 10 years ago, now that they have taken a hard look," panelist Linda Greer, PhD, of the Natural Resources Defense Council tells WebMD.

The contentious issue of dioxin's health effects has been debated for at least 15 years, but the EPA's board of advisors has at least a qualified endorsement for its position developed last year that dioxins do cause cancer in people.

"There's been a lot of pressure on the committee by outside forces, and there're people with very entrenched points of view. ... There were a lot of people who were arguing with each other, ... so the way that it all came out at the end was more politics than science," says Greer.

Don Barnes, PhD, who runs the EPA's science advisory board, disagrees.

"We came down saying it was a likely human carcinogen, but this should not ever be played that anyone thinks this stuff is not of concern," Barnes tells WebMD.

Industries that would bear the burden of dioxin reduction dispute the panel's finding, qualified though it is.

"Their draft report ... exemplified the inescapable fact that the science on dioxin, despite thousands of studies, is far from conclusive," the Chlorine Chemistry Council announced in a statement.

Dioxins are created from a variety of manufacturing and incinerating processes. They tend to stay in the environment for a long time and vary in toxicity. The defoliant Agent Orange is the most well known and perhaps most dangerous. Of particular concern is that dioxins accumulate in the food chain as livestock and fish consume them.


Even though there was no consensus about dioxin as a human carcinogen, there was total agreement about the need to reduce dioxin exposure.

"Consistent with basic environmental policy, it is important that the EPA continue to try to limit emissions (and human exposure to this class of chemicals)," says the draft document.

What is the EPA likely to do with this new guidance?

Greer says what's crucial about the new report is that it finally resolves the issue of how to develop safe levels of dioxin.

"The rubber has never hit the road on dioxin in these decisions because the health numbers, the potency factors ... have not been finalized ... and that's really kept things from going forward," says Greer.

The EPA can now do the calculations that should tell us how much meat we can safely eat, or what's necessary to clean up the atmosphere, she says. In sum, it's a matter of multiplying how much dioxin one consumes by total environmental exposure. The National Academy of Sciences will be taking an extensive look at the issue, which is being funded by the FDA and the USDA. These agencies, along with the EPA, would likely take the lead in enforcing a new dioxin policy.

Ultimately, the EPA is expected to put out a report on dioxins in October.

"The good news is the risk is 10 times less than it was 10 years ago, because we have 10 times less [dioxin]," says Barnes. "The bad new is we're seeing more and different kinds of effects. ... Our concern remains high."

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