EPA to Finish Stalled IRIS Assessments

by | Apr 14, 2011

The U.S. Environmental Protection Agency this week announced its plan to finalize four chemicals’ human health risk assessments as part of the Integrated Risk Information System (IRIS) program.

The delayed draft assessments – on hold since June 2010 – are for methanol, methyl tertiary-butyl ether (MTBE), ethyl tertiary-butyl ether (ETBE), and acrylonitrile.

The EPA held the assessments back because of a report written by the National Toxicology Program, which is administered by the National Institute of Environmental Health Sciences (NIEHS). The program noticed differences in opinion between its own findings and those of the Ramazzini Institute, a lab in Italy that conducts animal testing to evaluate the potential cancer-causing effects of chemicals.

The EPA and NIEHS started an independent pathology working group review of selected studies, in cooperation with the Ramazzini Institute, to resolve the differences of opinion. The review will continue over the next several months, and the cancer assessment for methanol will remain on hold until the study is completed.

However, the EPA has determined that it does not need Ramazzini Institute study results to continue with the assessment of MTBE, ETBE and acrylonitrile, including an assessment of cancer risks. Work on the assessments for these three chemicals will continue during the working group’s review.

IRIS is a human health assessment program that evaluates the risks of exposure to environmental contaminants. Through IRIS, the EPA provides human health risk assessments to support and direct the agency’s regulatory activities.

The agency uses information from IRIS when making decisions on regulations, such as the amount of a substance a company can safely discharge into a river or emit into the air.

Vincent Cogliano, IRIS’ newly-appointed acting director, recently described the program as “kind of the center of everything the EPA does scientifically.”

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