Academies Confirms Dioxin Dangers
Finds deficiencies in EPA review process
(Beyond Pesticides, July 13, 2006) The National Academies' (NA) National Research Council released a review of the Environmental Protection Agency’s (EPA) 2003 Dioxin Reassessment on July 11th confirming what numerous scientific panels have concluded over the past 15 years: dioxin is a potent cancer-causing chemical. According to NA, EPA did not sufficiently quantify the uncertainties and variabilities associated with the risks, nor did it adequately justify the assumptions used to estimate them.
"Although the NA review has confirmed that dioxin is a carcinogen, the EPA Dioxin Reassessment concluded this several years ago and recent studies have added additional weight to this conclusion," stated Dr. Richard Clapp, Professor of Environmental Health at Boston University School of Public Health. "Furthermore, there does not appear be safe 'threshold' for dioxin's carcinogenic effects. Evidence has accumulated since EPA began its reassessment in 1991 that dioxin also causes many other health problems even at low levels, such as developmental problems in children, immunologic problems in children and adults, reproductive problems in adults, and diabetes."
The committee that wrote the report recommended that EPA re-estimate the risks using several different assumptions and better communicate the uncertainties in those estimates. The agency also should explain more clearly how it selects both the data upon which the reassessment is based and the methods used to analyze them. "Failure to fully characterize uncertainty can convey a false sense of precision in the conclusions of the risk assessment," said committee chair David L. Eaton, a professor and associate vice provost for research at the University of Washington, Seattle. "EPA could improve the transparency and credibility of the assessment by more clearly identifying the assumptions used to support risk estimates and by updating them when significant new findings are made."
The NA review was the result of a last minute amendment to the 2003 EPA appropriations bill, which required NA to review EPA's reassessment if a White House interagency task force did not reach consensus on its review of the draft report.
"The first health assessment of dioxin was in 1985," said Lois Gibbs, CHEJ Executive Director. Gibbs's struggle to clean up dioxin in her Niagara Falls NY community at Love Canal has been credited with launching the grassroots environmental health movement. "Over the past 21 years, chlorine-based industries have demanded reviews, reassessments and analysis. Each re-assessment and review affirmed the findings and newer scientific data continues to strengthen the conclusions that dioxin is a serious public health threat. The chlorine-based industry is following the tobacco industry's strategies to keep information from the public. Enough is enough—let's get on with establishing health protective regulations around dioxin discharges and clean ups," said Gibbs.
Scientists at the Environmental Protection Agency (EPA) have long concluded dioxin and dioxin like compounds are highly toxic, but a strong coalition of industries responsible for generating the byproduct toxicant have successfully stalled progress on a 15-year study of the chemical. The EPA study—called the "Dioxin Reassessment"—still remains a draft, which has stymied the agency's development of federal regulations. However, EPA recently set a major precedent when they set the soil cleanup goal for dioxin at 30 parts per trillion (ppt) at the Escambia Wood Treating Co. Superfund site in Pensacola, FL.
Dow Chemical Company has been particularly aggressive in denying the toxicity of dioxin. The company's product line, which is heavily reliant on chlorinated chemical production, has resulted in communities contaminated with dioxin. Dow faces major liability for dioxin at its global headquarters in Michigan where the company has contaminated more than 50 miles of a river system that leads to Lake Huron, one of the Great Lakes. The company has repeatedly attempted to weaken cleanup standards to reduce the company's liability, while helping to create uncertainty at the federal level. The company has fought the state residential cleanup standard in Michigan, which is 90 ppt, although the federal government recently used 30 ppt for a site in Florida.
Dioxin contamination is particularly high in areas with dioxin sources like incinerators, smelters, pulp and paper mills, chemical factories or other industries that use chlorine. The disposal of polyvinyl chloride (PVC) plastic is the largest source of dioxin-forming chlorine in solid waste. PVC is the leading contributor of chlorine to four combustion sources— municipal solid waste incinerators, backyard burn barrels, medical waste incinerators and secondary copper smelters—that account for an estimated 80% of dioxin air emissions. Residents living near PVC chemical plants in Mossville, LA had three times more dioxin in their blood than the average U.S. citizen. Dioxin has been found at hundreds of Superfund toxic waste sites. It was a contaminant in Love Canal, and Agent Orange, the herbicide sprayed in Vietnam that resulted in major health impacts for Vietnam Veterans. Dioxin has been found in milk, cheese, beef, pork, fish, chicken, birds, deer, turkey, squirrel, and worms, as well as soil and sewage sludge.
Copies of Health Risks From Dioxin and Related Compounds: Evaluation of the EPA Reassessment are available from the National Academies Press; tel. 202-334-3313 or 1-800-624-6242 or on the Internet at http://www.nap.edu.
This article was excerpted in part from a July 10, 2006 press release by the Center for Environmental Health and Justice (CHEJ), and a July 11, 2006 press release by the National Acadamies. For more information, see "Chronological History of US EPA's Public Health Assessment of Dioxin" and "Dioxin Fact Sheet" at www.chej.org/dioxin.
Take Action: Learn about safer alternatives to Dow products at Beyond Pesticides' Dow Consumer Campaign.