U.S. Sen. David Vitter (R-La.), top Republican on the Environment and Public Works Committee, and Committee Members Jim Inhofe (R-Okla.) and Mike Crapo (R-Idaho) today sent a letter to acting Administrator of the U.S. Environmental Protection Agency (EPA), Bob Perciasepe, and Dr. Ken Olden, Director of the EPA National Center for Environmental Assessment, requesting clarification of the process EPA is using to ensure current draft chemical assessments take into account recommended changes from the National Academy of Sciences (NAS).

In April 2011, after reviewing the EPA's formaldehyde assessment, NAS issued its final report with broad recommendations to fundamentally reform the Integrated Risk Information System (IRIS) process. Congress then asked NAS to conduct a more comprehensive review of IRIS, which will provide detailed recommendations that should ensure future chemical assessments will be based upon the best available science and methodologies for reviewing scientific information. It has been unclear how EPA has applied NAS recommendations to the assessments that were already underway when the report was released.

The Senators wrote, "EPA's expressed commitment to improving the IRIS process is encouraging; yet we remain concerned by the Agency's questionable level of transparency regarding what and how these changes will improve the assessments of substances currently in development and the timelines associated with completing these assessments."

In the letter the Senators also mention a draft EPA guidance that had been leaked to the media, but not shared with Congress, that suggests EPA may consider barring qualified experts from peer review panels based on affiliation, at the suggestion of environmental groups.

Click here to read the letter from Sens. Vitter, Inhofe, and Crapo to acting Administrator Perciasepe and Dr. Olden.