Defense Environment Alert
April 23, 2002

DRAFT GAO REPORT SUPPORTS LONG-AWAITED EPA DIOXIN REASSESSMENT

Conuressional investigators are backing EPA's long-awaited scientific assessment of the risks posed by dioxin, providing key support for the agency even as it faces new congressional scrutiny into its decades-long effort that could have a profound impact on the agency's waste, water, air and toxics regulatory programs.

A draft General Accounting Office (GAO) report requested by Sens. John Breaux (D-LA) and Thad Cochran (R-MS) finds that EPA's conclusion that dioxin and "dioxin-like" compounds could adversely affect human health at lower exposure levels than previously thought is consistent with the findings of the World Health Organization (WHO), although the agencies differ on some key issues. The draft report is available on InsideEPA.com. Seepage 2 for details.

GAO also finds that EPA's work "largely reflects the recommendations and suggestions provided to the agency by the two most recent independent peer review panels." However, the investigators find that because some of EPA's dietary survey data is out of date, the agency's ability to specify the current impact of exposures is limited because dioxin releases have been decreasing as a result of EPA air quality rules for more than a decade.

However, it is unclear what effect the draft GAO report will have on the agency's ability to finalize the dioxin study as key lawmakers spar over the reassessment. Rep. James Walsh (R-NY), chairman of the VA-HUD Appropriations Subcommittee, called on the agency earlier this year to initiate a National Academy of Sciences (NAS) review of the reassessment that he acknowledges may further delay its finalization. However, Sen. James Jeffords (I-VT) has introduced legislation that would require EPA to finalize the study in 90 days.

But EPA officials have still not decided how to respond to Walsh's request. Sources say agency staff in early April forwarded a draft response to EPA Administrator Christine Todd Whitman indicating that the agency plans to look into the possibility of an NAS review but that a response has yet to be finalized.

EPA sources say that, although internal deliberations about the reassessment continue, the agency plans to release the study this summer for a final round of interagency review at the assistant secretary level at both the U.S. Department of Agriculture and the Food & Drug Administration's parent agency, the Department of Health & Human Services.

In the draft report, GAO addresses a host of issues Walsh raised in a February letter to EPA, including "substantial questions" raised by peer reviewers, whether dioxin and related compounds should be classified as "known" or "likely" human carcinogens, and whether there is a "safe" level below which people can be exposed. Walsh also raised concerns about a method used to index the potency of various mixtures of dioxin-like compounds -- known as Toxic Equivalency Factors (TEFs).

However, the draft GAO report finds that EPA has responded to the peer review panelist's feedback by "performing additional analyses or explaining that the data currently available are not yet sufficient to address the recommendation or suggestion."

The investigators find that, overall, both GAO and EPA agree that: dioxins can cause of variety of cancer and noncancer health effects; that they act in the same way in animals and humans; and that some effects could occur at or near the levels to which the general population is now being exposed. The investigators also conclude that although the method for estimating the potency of mixtures or "TEF" approach "may overstate or understate the concentrations of dioxins in the foods, it is the internationally accepted scientific method for risk assessments of dioxins."

However, GAO notes that EPA does not share WHO's position that there is a safe level below which people can be exposed. Moreover, WHO differs with EPA's stance that dioxin-like compounds and mixtures should be classified as "likely" human carcinogens.

EPA's conclusion that current levels of the contaminant in the United States population hover around acceptable risk standards has raised alarms among food agencies whose officials have already commissioned an NAS study on managing the risks from food.

GAO was charged to address dietary exposure information, the compatability of EPA's and WHO's methods, and EPA's responsiveness to independent peer reviewers. The investigators did not render a judgment on the scientific merits of the assessment. -- Steven Gibb