Letter dated - 3/14/2012 Environmental Protection Agency


March 14, 2012




Acting Assistant Administrator Lek Kadeli

Office of Research and Development

Environmental Protection Agency

Washington, DC 20460


RE:  EPA’s Integrated Risk Information System’s Toxicological Review of Hexavalent Chromium (1)


Dear Acting Assistant Administrator Kadeli:


The Office of Advocacy (Advocacy) commends the Environmental Protection Agency (EPA) for adopting the recommendations of the external peer review panel for the above referenced draft Integrated Risk Information System (IRIS) assessment for hexavalent chromium (oral exposure assessment), and for responding to small businesses requests to consider and incorporate forthcoming and recently concluded scientific studies into the assessment.  EPA’s actions will enhance the scientific integrity of this review and will help to increase confidence in the IRIS program more generally.

IRIS is a human health assessment program that evaluates risk data on effects that may result from exposure to environmental contaminants.  IRIS compiles a database that describes the health effects of substances and contains quantitative and descriptive information on cancer and non-cancer effects.  The draft IRIS assessment for hexavalent chromium was released for peer review and public comment in September 2010.  In their July 2011 post-meeting comments, the independent expert peer review panel urged EPA to consider upcoming results of peer-reviewed research before finalizing the assessment.  This research is likely to provide relevant scientific data.

On February 28, 2012, EPA announced that it would delay its pending IRIS assessment of the risks of hexavalent chromium to draft a new version.  This new version will weigh the results of recent and forthcoming peer-reviewed primary research on hexavalent chromium before finalizing the IRIS assessment.  EPA anticipates that the hexavalent chromium draft final oral and inhalation assessments will be released for public comment and external peer review in 2013.

Advocacy is pleased that EPA is taking seriously its commitment to rigorous independent expert peer review as well as its commitment to using the best available science.  We look forward to working with EPA to further improve IRIS. 







Winslow Sargeant, Ph.D.

Chief Counsel for Advocacy




Sarah Bresolin Silver

Assistant Chief Counsel

Office of Advocacy



Copy to:  The Honorable Cass R. Sunstein, Administrator

                Office of Information and Regulatory Affairs

                Office of Management and Budget




  1. “IRIS Toxicological Review of Hexavalent Chromium.”  Available at: http://cfpub.epa.gov/ncea/iris_drafts/recordisplay.cfm?deid=221433.