Feb 14, 2012

U.S. EPA Releases Final Health Assessment for Chemical Solvent

Report classifies ‘perc’ as likely carcinogen, agency to revise drinking water strategy

The U.S. Environmental Protection Agency (EPA) 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, and 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 significant exposure that could pose concerns. EPA already has clean air standards for dry cleaners that use perc, including requirements that will phase out its use in residential buildings by Dec. 21, 2020. EPA has also set limits for the amount of perc allowed in drinking water and levels for cleaning up perc at Superfund sites throughout the U.S., which will be updated in light of the IRIS assessment.

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; and
• 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. The assessment has undergone several levels of independent peer review, including agency review, interagency review, public comment and external peer review by the National Research Council.