An important EPA report on the dangers of dioxin has been fifteen years in the making. Now, the National Academies of Science say EPA still has more work to do. Living on Earth’s Jeff Young reports on why the effort is taking so long, and what’s riding on the final conclusions.
CURWOOD: From the Jennifer and Ted Stanley Studios in Somerville, Massachusetts - this is Living on Earth. I’m Steve Curwood.
CURWOOD: Dioxin, in particular what’s called TCDD dioxin, is one of the most toxic chemicals ever studied, with documented health effects from exposure to trillionths of a gram. The health risks include cancer, immune deficiencies, reproductive disorders and neurological deficits.
Dioxin can be an unwanted by-product from chlorinated pulp paper, pesticides and plastics. Yet for over fifteen years regulators at the US Environmental Protection Agency have wrestled with a comprehensive report on just how dangerous dioxin is. Now the National Academies of Science say EPA’s job is still not quite finished. Living on Earth’s Jeff Young reports on why the study has taken so long, and what’s riding on the outcome.
YOUNG: The Environmental Protection Agency started to update its science on dioxins in the early years of the Bush administration. Not this Bush administration—the last one.
CLAPP: This was under bush the first – George H W Bush was president and Administrator Reilly said we’ll do it for 18 months.
YOUNG: That’s Boston University public health professor Richard Clapp. Clapp served on the board of scientists who would advise then-EPA Administrator William Reilly on the reassessment of dioxin dangers.
CLAPP: Well, it wasn’t 18 months. It’s now 15 years.
YOUNG: EPA’s dioxin report became an exhaustive review of one of the most thoroughly studied groups of toxic compounds. The draft result, released three years ago, said dioxins could cause cancer in humans in very low amounts and cataloged other ill effects in development, immune and reproductive systems—even as a possible contributor to diabetes.
EPA used statistical models to estimate the risk at very low levels of exposure, and their method found that there might be no safe dose of dioxin. But there was disagreement about that. So the government asked the National Academies of Science to weigh in. The NAS did not question whether dioxin can cause illnesses but said EPA’s method may have overstated some risks, particularly of cancer, at tiny doses. NAS Panelist Joshua Cohen says the agency’s work is not quite done.
COHEN: what we are encouraging EPA to do is to look at the full range of plausible scientific assumptions. And in some cases that may imply higher risk in some cases it may imply lower risks. But it’s important for risk managers to understand how much we know and how much we don’t know; how imprecise are our estimates.
YOUNG: Just what that means for EPA’s report seems open to interpretation. Greg Merrell is with the Chlorine Chemistry Council, which represents companies that produce dioxin emissions.
MERRELL: There’s a great deal of uncertainty, that’s what I heard. I’m pleased that the national academy of science identified a lot of work that needs to be done.
YOUNG: Public health professor Clapp disagrees. He says the Academy report does not change EPA’s main conclusions.
CLAPP: And NAS has, in a sense, said although it still needs some tweaking and dotting of i’s crossing of t’s, the bottom line is, this is bad stuff. This dioxin, and the dioxin-like compounds, are harmful.
YOUNG: Once it’s finalized, the EPA report will guide state and federal agencies in decisions on how strictly dioxin should be regulated. Clapp says that’s a major reason why the EPA report took so long. He says industry-connected scientists delayed conclusions by the advisory board he served on—at one point even demanding additional study of a claim that a little dioxin might be healthy.
CLAPP: Then it became, ok, well, maybe actually there’s, uh, the dose at low levels of exposure maybe dioxin’s actually good for you. So there was another go-around about that and that just muddied up the works.
The Chlorine Chemistry Council’s Merrell denies his industry benefits from delaying the dioxin report.
MERRELL: I think industry has always been concerned about making sure that EPA on this issue as well as all other issues uses the most current science so that it can come to the right conclusions.
YOUNG: Merrell points out that his industry has cut dioxin emissions nearly 90 percent over the last 20 years. But because dioxin persists in the environment and builds up in the food chain, many companies still face potential liability for cleaning up old contamination.
Joy Towles Ezell lives near one such site—a pulp mill, which once pumped dioxins into a Florida river. She traveled from Perry, Florida, to Washington for the Academy briefing.
EZELL: I sure did. It’s that important to me and to my community because we have people there at home who are very sick. The fish in the river—there are two species of fish in the river that are actually changing sex, which is pretty scary. I mean, that should be our canary in a coalmine and EPA should be paying attention to that.
YONG: Local activists like Ezell wonder how long they have to wait for a final answer and just how precise the science has to get before regulators will act. Academy panelists say they think the EPA should be able to address their concerns and complete the dioxin report within a year.
For Living On Earth, I’m Jeff Young in Washington.
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