The EPA has posted the final health assessment for tetrachloroethylene – also known as perchloroethylene, or perc – to EPA’s Integrated Risk Information System (IRIS) database. Perc is a chemical solvent widely used in the dry cleaning industry. It is also used in the cleaning of metal machinery and to manufacture some consumer products and other chemicals. Confirming longstanding scientific understanding and research, the final assessment characterizes perc as a “likely human carcinogen.” The assessment provides estimates for both cancer and non-cancer effects associated with exposure to perc over a lifetime.
 
EPA does not believe that wearing clothes dry cleaned with perc will result in exposures which pose a risk of concern. EPA has already taken several significant actions to reduce exposure to perc. EPA has clean air standards for dry cleaners that use perc, including requirements that will phase-out the use of perc by dry cleaners in residential buildings by December 21, 2020. EPA also set limits for the amount of perc allowed in drinking water and levels for cleaning up perc at Superfund sites throughout the country, which will be updated in light of the IRIS assessment. 
 
“The perc health assessment released today will provide valuable information to help protect people and communities from exposure to perc in soil, water and air,” said Paul Anastas, assistant administrator for EPA’s Office of Research and Development. “This assessment emphasizes the value of the IRIS database in providing strong science to support government officials as they make decisions to protect the health of the American people.”

The toxicity values reported in the perc IRIS assessment will be considered in:
 
• Establishing cleanup levels at the hundreds of Superfund sites where perc is a contaminant
• Revising EPA’s Maximum Contaminant Level for perc as part of the carcinogenic volatile organic compounds group in drinking water, as described in the agency’s drinking water strategy
• Evaluating whether to propose additional limits on the emissions of perc into the atmosphere, since perc is considered a hazardous air pollutant under the Clean Air Act
 
The assessment replaces the 1988 IRIS assessment for perc and for the first time includes a hazard characterization for cancer effects. This assessment has undergone several levels of rigorous, independent peer review including: agency review, interagency review, public comment, and external peer review by the National Research Council. All major review comments have been addressed.
 
EPA continues to strengthen IRIS as part of an ongoing effort to ensure the best possible science is used to protect human health and the environment. In May 2009, EPA streamlined the IRIS process to increase transparency, ensure the timely publication of assessments, and reinforce independent review. In July 2011, EPA announced further changes to strengthen the IRIS program in response to recommendations from the National Academy of Sciences. EPA’s peer review process is designed to elicit the strongest possible critique to ensure that each final IRIS assessment reflects sound, rigorous science.
 
More information on the perc IRIS assessment: www.epa.gov/iris/subst/0106.htm
 
More information on perc: epa.gov/oppt/existingchemicals/pubs/perchloroethylene_fact_sheet.html
 
More information on IRIS: www.epa.gov/IRIS