On September 28, EPA published its long-awaited Toxicological Review of Trichloroethylene (TCE), characterizing TCE as “carcinogenic to humans” and provided new toxicity values for both cancer and noncancer effects in its Integrated Risk Information System (IRIS) database. EPA had withdrawn the toxicity values for TCE from IRIS in 1989, following disagreements with peer reviewers regarding the classification of TCE as a “probable human carcinogen.” For over 20 years, as EPA, the National Research Council, and other scientists have worked to develop consensus on the toxicological properties of TCE, risk assessors have used alternative values from such sources as CalEPA and other state agencies. All of the new IRIS cancer and noncancer toxicity values are more stringent than the alternative toxicity values EPA has used to calculate regional screening levels (RSLs). Revised RSLs based on the new IRIS toxicity values will be similarly more stringent, especially for residential exposures.
For more information, contact Judi Durda at jdurda@integral-corp.com or 410.573.1982 (ext. 14) or Kathleen Neuber at kneuber@integral-corp.com or 609.259.5415.