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EPA Places Four IRIS Assessments on Hold Pending Review

Release Date: 06/15/2010
Contact Information: Latisha Petteway,, 202-564-3191, 202-564-4355

WASHINGTON – The U.S. Environmental Protection Agency (EPA) announced today that it is holding four of its ongoing IRIS (Integrated Risk Information System) assessments pending a review of some of the underlying studies used in the assessments. EPA conducts IRIS assessments to determine the impact of specific chemicals on human health.

EPA is holding these assessments due to a report from the National Toxicology Program (NTP) that outlines a recent review of a research study completed by the Ramazzini Institute, a lab in Italy that conducts animal testing to evaluate the potential cancer-causing effects of chemicals. The report discusses findings from a recent assessment by NTP pathologists of an animal study on methanol. NTP’s report recommends that further pathology reviews be carried out to resolve differences of opinion between NTP scientists and the Ramazzini Institute in the diagnoses of certain cancers reported in the study.

Out of an abundance of caution and to ensure the agency’s chemical assessments are grounded in the soundest possible science, EPA undertook a thorough review of all ongoing and previous chemical assessments to determine which, if any, relied substantially on cancer testing from the Ramazzini Institute.

EPA found six assessments that significantly rely on data from Ramazzini cancer studies:

Assessments currently in progress: EPA found four ongoing chemical assessments – on methanol, MTBE, ETBE and acrylonitrile – that rely significantly on cancer data from the Ramazzini Institute. EPA has placed those assessments on hold and will determine whether the questions raised by NTP will require EPA to revise the assessments or take additional action to verify the data used in these assessments. EPA also postponed an August 23 meeting of the agency’s Science Advisory Board, which had been previously scheduled to review the draft methanol assessment.

    Previously completed assessments: Out of more than 540 completed assessments posted on the Integrated Risk Information System (IRIS), EPA identified two – Vinyl Chloride and 1,1- Dichloroethylene – that relied substantially on findings from Ramazzini Institute cancer studies. EPA is reviewing these assessments as well to determine what action is needed to assure their scientific integrity.

    EPA will continue its review to determine if any other assessments are significantly impacted.