EPA Links Dioxin To Cancer

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EPA Links Dioxin To Cancer

By Skrzycki and Joby Warrick

Washington Post Staff Writers

Wednesday, May 17, 2000

The Clinton administration is preparing to dramatically raise its estimate

of health threats from dioxin, citing new evidence of cancer risk from

exposure to the toxic chemical compound.

A draft of a long-awaited report by the Environmental Protection Agency

concludes for the first time that dioxin is a " human carcinogen. " The report

notes that emissions of dioxin have plummeted from their peak levels in the

1970s but still may pose a significant cancer threat to some people who

ingest the chemical through foods in a normal diet.

Dioxin comes from both natural and industrial sources, such as medical and

municipal waste incineration and paper-pulp production. The chemical enters

the food chain when animals eat contaminated plants. Dioxin then accumulates

in the fat of mammals and fish. It has been linked to several cancers in

humans, including lymphomas and lung cancer.

For a small segment of the population who eat large amounts of fatty foods,

such as meats and dairy products that are relatively high in dioxins, the

odds of developing cancer could be as high as 1 in 100, the report says.

That estimate places the risk 10 times as high as the EPA's previous

projections.

Exposure to dioxin occurs over a lifetime, and the danger is cumulative, the

report said. Studies have found that people all over the globe have some

dioxin in their bodies.

The report, obtained by The Washington Post, links low-grade exposure to

dioxin to a wide array of other health problems, including changes in

hormone levels as well as developmental defects in babies and children.

It also concludes that children's dioxin intake is proportionally much

higher than adults' because of the presence of the chemical in dairy

products and even breast milk.

" It's the Darth Vader of toxic chemicals because it affects so many systems

[of the body], " said Clapp, a cancer epidemiologist at Boston

University's School of Public Health. " The amounts are coming down, but even

small amounts are harmful. "

The EPA's draft assessment, if finalized in its current form, would solidify

dioxin's status as one of the most potent chemical toxins known to science.

Although the risk from dioxin varies widely--and may be nearly zero for many

people--the findings suggest that dioxin already contributes to a

significant number of cancer deaths each year. Environmentalists,

extrapolating from the EPA's risk findings, have estimated that about 100 of

the roughly 1,400 cancer deaths occurring daily in the United States are

attributable to dioxin.

Officials predicted yesterday that the report would stimulate many questions

about the safety of the food supply. Administration officials said, however,

that the higher dioxin risks should not discourage people from eating

nutritious foods and following dietary guidelines emphasizing low-fat foods.

The report stressed that mothers should continue to breast-feed because the

benefits far outweigh the risk of dioxin exposure.

In an indication of the potentially far-reaching implications of the report,

the White House has intervened in an unusual way to coordinate its release.

The report is scheduled to be released in June and will be evaluated by

scientific reviewers.

It's not clear that the findings will lead to new regulations on dioxin

emissions, but EPA briefing papers discussed several strategies for reducing

human exposure to the chemical, including better monitoring.

The findings came as a surprise even to EPA policymakers who have tracked

slowly falling levels of dioxin in the environment--the result of a series

of tough new regulations on dioxin-emitting industries.

The EPA said industrial emissions of dioxins have been reduced some 80

percent between 1987 and 1995.

" We're heading in the right direction because we're seeing dioxin levels

decrease, " said one administration official who spoke on the condition of

anonymity. But while dioxin levels in the population are declining, " our

ability to understand the risk has improved, " the official said.

Dioxin came to public attention as the contaminant in Agent Orange, a

controversial herbicide used by U.S. forces in Vietnam. In 1983, the EPA

forced the evacuation and demolition of the entire town of Times Beach, Mo.,

after the discovery of dioxin contamination on city streets.

Industry scientists have long accused the EPA of overstating the threat from

dioxin, and many believed the agency's review would result in a downgrading

of the official risk estimate.

C.T. Kip Howlett, vice president and executive director of the Chlorine

Chemistry Council, said the EPA has a conservative view of the health risks

of dioxin and they are " out of sync " with the rest of the world's view on

safe levels of the chemical.

Howlett said the agency " has a real problem on it's hands " in expressing

apocalyptic concern about dioxin, while also stressing that the food supply

is safe, breast feeding is the right thing to do and regulatory initiatives

are working.

" There are a lot of things in this report that are counterintuitive to what

the facts are, " Howlett said.

Holman, chief regulatory counsel of the U.S. Chamber of Commerce, said

no industry wants to produce dioxin--which is an unintended by-product of

combustion-- " but let's make sure we have sound science before we regulate

down to a zero level where it's clearly not warranted. "

Environmentalists supported the EPA's findings but raised concerns that the

agency would use falling dioxin levels as an excuse to delay any further

tightening of regulations to control dioxins.

" They seem to be taking a triage approach, not worrying about emissions but

dietary exposures of human beings, " said Rick Hind of Greenpeace

International's toxics program. " That suggests they can't walk and chew gun

at the same time. "

The agency's understanding of dioxin has improved since the agency began

in-depth studies in 1991, and this installment is particularly important

because it includes results of landmark human epidemiological studies from

Europe and the United States.

In a briefing to EPA managers on May 10, the agency said it expected " many

stakeholders to take dramatic action when the draft reassessment is

released, " and pressure from other interests given the " extraordinary "

findings of the reassessment.

For the first time, the agency's draft report classifies the most potent

form of dioxin--2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)--as a " human

carcinogen, " a step above the previous ranking of " probable carcinogen. "

More than 100 other dioxin-like compounds were classified as " likely " human

carcinogens.

Over the past five years, the EPA has imposed regulations on major dioxin

emitters, including municipal waste combustors, medical waste incinerators,

hazardous waste incinerators, cement kilns that burn hazardous waste, pulp

and paper operations, and sources of PCBs.

When those regulations become fully effective over the next few years, the

agency expects further declines of dioxin levels.

" We still have a certain amount of dioxin circulating in the environment. We

need to focus on the idea of reducing exposure and not simply going after

all sources to the environment, " said one administration official.

One source likely to be targeted is uncontrolled residential waste burning,

such as burning trash in back yards, particularly in rural areas, EPA

briefing papers said. Such burning is " one of the largest unaddressed dioxin

sources and one that could have a disproportionally large contribution to

the food supply. "

The agency also is discussing the possible regulation of other sources such

as sludge disposal from privately owned waste-treatment facilities and the

regulation of other air sources of pollution.

Sources said that there have been lengthy discussions at the EPA on how to

release the report and answer questions stemming from it.

Several federal agencies have been involved in the preparation of the report

and are expected to participate in the review of it. Agencies such as the

Agriculture Department and the Food and Drug Administration, as well as the

Food Safety Council, are readying their own responses to questions about the

safety of the food supply, advice on following the dietary guidelines and

breast feeding.

" People were not expecting this was an issue they had to deal with, " an

administration official said. " Over the last eight years there have been

regulations that have already cut dioxin emissions from the most likely

sources. "

© 2000 The Washington Post