What is tetrachloroethylene?
Tetrachloroethylene is a synthetic chemical that is widely used for dry cleaning fabrics and for metal-degreasing operations. It is a nonflammable liquid at room temperature. It evaporates easily into the air and has a sharp, sweet odor. Most people can smell tetrachloroethylene when it is present in the air at a level of 1 part tetrachloroethylene per million parts of air (1 ppm) or more, although some can smell it at even lower levels. Other names for tetrachloroethylene include perchloroethylene, PCE, and PERC.
Where could I be exposed to tetrachloroethylene?
Most exposures to tetrachloroethylene occur in the workplace through breathing vapor and direct contact with the liquid. Exposure to the general public typically occurs from environmental sources (contaminated air and water) and from consumer products. Products that may contain tetrachloroethylene include water repellents, silicone lubricants, fabric finishers, spot removers, adhesives, and wood cleaners. Common environmental levels of tetrachloroethylene (called background levels) are several thousand times lower than levels found in some workplaces. Water polluted with tetrachloroethylene may have levels greater than 1 ppm. In soil, background levels are typically 100–1,000 times lower than 1 ppm. However, the background level of tetrachloroethylene in air is usually less than 1 part in 1 billion parts of air (ppb). The air close to dry cleaning shops and tetrachloroethylene waste sites has levels of tetrachloroethylene higher than background levels.
Most of the tetrachloroethylene released into the environment comes from its use to remove grease from metals. It can also enter the air and water when it is disposed at waste sites. It evaporates easily, but can stay in the soil and in groundwater for a long time. Because tetrachloroethylene can travel through soils quite easily, it can get into underground drinking water supplies. If it gets into underground water, it may stay there for many months without being broken down. Tetrachloroethylene does not readily bioaccumulate in animals that live in water, such as fish, clams, and oysters.
What are the health risks of tetrachloroethylene?
Tetrachloroethylene has been used medicinally in the past as a general anesthetic, and at high concentrations causes loss of consciousness. When concentrations in air are high—particularly in closed, poorly ventilated areas—acute exposures can cause dizziness, headache, sleepiness, confusion, nausea, difficulty in speaking and walking, unconsciousness, and death.
Results of animal studies, conducted with tetrachloroethylene at concentrations higher than those of typical exposures, have found that tetrachloroethylene can cause liver and kidney damage. Animal studies have also shown that offspring of pregnant animals exposed to excessive levels of tetrachloroethylene can develop behavior problems.
How likely is tetrachloroethylene to cause cancer?
Although it has not been shown to cause cancer in people, the U.S. Department of Health and Human Services (DHHS) has determined that tetrachloroethylene may reasonably be anticipated to be a human carcinogen based on animal studies. The International Agency for Research on Cancer (IARC) has determined that tetrachloroethylene is a probable human carcinogen. The U.S. Environmental Protection Agency (EPA) has classified tetrachloroethylene as likely to be carcinogenic in humans by all routes of exposure.
How can I protect myself from tetrachloroethylene?
People who work with tetrachloroethylene are at greatest risk of exposure. If you work somewhere that uses tetrachloroethylene, follow safe work practices and use appropriate personal protective equipment. For the general public, exposure can be reduced by avoiding products containing tetrachloroethylene and choosing dry cleaning methods that do not use tetrachloroethylene.
Where can I get more information on tetrachloroethylene?
- Agency for Toxic Substances and Disease Registry ToxFAQs for Tetrachloroethylene (PERC)