EP Releases Reanalysis of Dioxin Risk for Public Comment

Dioxin is one of those "ethyl methyl megadeath" substances that generates lots of fear in the public, perhaps out of proportion to the actual danger it poses. The Kanawha River and certain other waterbodies are listed as impaired for dioxin, although the water quality criterion is set at such a low level that even background levels could trigger a finding of impairment. It has been studied and restudied, most recently by the National Academy of Sciences, which completed its review in 2006. EPA reviewed that report and has now issued its own critique of the NAS conclusions. EPA's analysis is now available for public comment.

WASHINGTON - The U.S. Environmental Protection Agency (EPA) has reached a significant milestone toward the completion of the agency’s dioxin reassessment with the public release of its draft scientific report, EPA’s Reanalysis of Key Issues Related to Dioxin Toxicity and Response to NAS Comments. The draft dioxin report is EPA’s response to key comments and recommendations made by the National Academy of Sciences on the agency’s draft dioxin reassessment. EPA is moving forward with Administrator Lisa P. Jackson’s commitment to complete the long-awaited dioxin reassessment. This comprehensive human health and exposure risk assessment on dioxin, one of the most toxic environmental contaminants, aims to protect the health of the American public. The draft report will now undergo scientific peer review by independent, external experts as well as public review and comment.

EPA previously asked the National Academy of Sciences (NAS), the science advisors to the nation, to review EPA’s 2003 draft dioxin reassessment. The NAS completed its review in 2006. The draft report released today contains the agency’s response to key comments and recommendations in the NAS’s 2006 report. EPA’s draft report also includes significant new analyses that relate to issues raised by the NAS, including potential cancer and non-cancer human health effects that may result from exposures to dioxins. Thus, this draft dioxin report includes an oral reference dose (RfD) for TCDD -- the most well-studied and considered to be among the most toxic of the dioxin-like compounds. An RfD was not in the 2003 draft dioxin reassessment.

As part of EPA’s commitment to scientific quality, integrity, and transparency, EPA’s draft scientific report will undergo external peer review by an expert panel of scientists convened by EPA’s Science Advisory Board (SAB) in July 2010. Public comments on this draft report are encouraged, and a Federal Register Notice published today provides details on how to submit comments. EPA will use the feedback and recommendations of the expert panel, as well as the public comments, to update and complete its draft dioxin reassessment.

Dioxin is a general term that describes a group of hundreds of chemicals that are highly persistent in the environment. Dioxins are formed during combustion or burning. Sources of dioxins include commercial or municipal waste incineration; the burning of fuels like wood, coal, or oil; and natural processes such as forest fires.

While dioxin levels in the United States environment have been declining for the last 30 years due to reductions in emissions from man-made sources, the chemicals break down so slowly that dioxins from past releases will still be in the environment for many years.

EPA and other federal agencies have updated a series of questions and answers to provide the public with general information on dioxins, including what they are, where they can be found, and major sources of dioxins. They also discuss possible effects of dioxin exposure in humans, include advice about consumption of food that might contain dioxins, and explain the review process for the dioxin reassessment. To view the questions and answers: http://www.fda.gov/Food/FoodSafety/FoodContaminantsAdulteration/ChemicalContaminants/DioxinsPCBs/ucm077524.htm

To read the draft report: http://www.epa.gov/dioxin

Federal Register Notice with details on the public comment process: http://www.gpo.gov/fdsys/pkg/FR-2010-05-21/html/2010-12280.htm

EPA’s Risk Assessment Process: http://epa.gov/riskassessment/basicinformation.htm#arisk