EPA Revises Risk Guidelines

ENVIRONMENT

The Environmental Protection Agency last week released new guidelines it will follow when assessing the risks posed by carcinogenic chemicals.

The guidelines are similar to a draft released in 2003 (C&EN, March 10, 2003, page 13). They make revisions to the methods that EPA has used since 1986 to calculate cancer risks from exposure to chemicals, says William H. Farland, EPA acting deputy assistant administrator for science.

Formerly, EPA started its risk assessments by using so-called default assumptions, which are fallback positions designed to protect public health when the agency lacks data. EPA would switch from these assumptions only if experimental data suggested that it should do so.

Under the new guidelines, EPA will analyze all available data before resorting to default assumptions, Farland says.

In addition to the guidelines, the agency issued a companion document addressing childhood cancer and cancer later in life for adults exposed to a carcinogen as children. It says children exposed to DNA-damaging chemicals have a greater risk of developing cancer than do similarly exposed adults.

The agency developed its new guidelines over several years with input from the public. The revision is broadly viewed as a scientific improvement over EPA's 1986 guidelines.

The Natural Resources Defense Council (NRDC), however, says the White House at the last minute inserted a section into the document that will give industry more influence over EPA's risk assessments.

"Chemical companies will be able to pummel any new safeguard to death," says Jennifer Sass, NRDC senior scientist.

An official with the White House Office of Management & Budget says of the added section, "The change authorizes, but does not require, the use of formal probability judgments by scientists" as part of EPA's carcinogen risk assessments.

This technique is called expert elicitation. It would apply when EPA lacks enough peer-reviewed data to characterize a compound as a cancer risk. Expert elicitations would bring together specialists in various aspects of risk assessment--for example, dose-response evaluation--to review the data.

Based on their judgment, the experts would develop probabilities for specific outcomes from exposure to a chemical, Sass says. She criticizes the technique as costly, time-consuming, and shielded from public view.

Under the guidelines, EPA could conduct an expert elicitation as part of a risk assessment. Or, according to Sass, industry could sponsor an expert elicitation and then turn the results over to EPA, which would allow the chemical industry more influence over EPA's policy decisions on carcinogenic substances, she says.

James Solyst, American Chemistry Council senior director for science policy, tells C&EN that his organization did not ask the White House to place the language on expert elicitation into the guidelines. The guidelines are available on the Web at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=116283.