Tetrachloroethylene is a dry-cleaning agent and industrial degreaser that often goes under the name perchloroethylene (PERC). The National Institute of Occupational Safety and Health estimates that 650,000 U.S. workers are exposed to PERC annually. PERC enters the environment through evaporation or through transport into groundwater and drinking water supplies. Through widespread use it has become a frequent drinking water contaminant, and it is present in approximately half of the nation's Superfund sites.
PERC has a low odor threshold and its smell is that associated with a dry-cleaning establishment. High levels of PERC released in workplace accidents can produce loss of consciousness and death. There is some evidence that longer-term exposures to lower levels at the workplace can lead to kidney and liver damage, cancer, neurological impairment, including changes in memory and learning, and to problems with visual perception. Reproductive and developmental effects have been suggested.
Whether any of these effects occur at the much lower levels present in the general environment is controversial. There is increased pressure to regulate PERC because of particular concern for children living in apartment buildings above dry-cleaning establishments, and because as a chlorinated compound it can be a precursor of dioxins.
BERNARD D. GOLDSTEIN
New York State Department of Health (1997). Tetrachloroethylene (PERC) in Indoor and Outdoor Air: Fact Sheet. Albany, NY: Author.
U.S. Health Department of Health and Human Services (1997). Toxicological Profile for Tetrachloroethylene. Washington, DC: Public Health Service, Agency for Toxic Substances and Disease Registry.