Tetrachloroethylene (PCE) is a volatile solvent with important commercial applications. It has been detected in the ambient air of a variety of urban and nonurban areas of the United States. It has less frequently been detected in water but has been monitored generally at levels of 1 ppb or less. The lowest-observed-adverse-effect-level, based on central nervous system dysfunction, is about 100 ppm (678 mg/cu m). Toxicity testing in experimental animals, coupled with limited human data, suggests that long-term exposure of humans to ambient levels of PCE is not likely to represent a health concern. At the current time, the teratogenic potential of PCE for humans is unknown; the mammalian animal tests performed to date do not indicate any significant teratogenic potential. Although PCE epoxide has been found to be positive with respect to mutagenicity in bacterial systems, the data on pure PCE suggest that if it is mutagenic, it is a weak mutagen. PCE has been demonstrated to induce malignant tumors of the liver in mice. This constitutes limited evidence that PCE may be carcinogenic in humans. Because existing epidemiologic data for PCE is inconclusive, the overall ranking according to the criteria of the International Agency for Research on Cancer (IARC) would suggest that PCE is possibly carcinogenic in humans.

Includes bibliographical references. "Jan.1984" "EPA-600/8-82-005B" Second external review draft. -- Accompanying memo. "Revision clarifying the carcinogenicity conclusions of the Draft Health Assessment Document for Tetrachloroethylene (Perchloroethylene), and repopening of public comment period." -- Accompanying memo. "This document is a preliminary draft. It has not been formally released by EPA and should not at this stage be construed to represent Agency policy. It is being circulated for comment on its technical accuracy and policy implications."