What is tetrachlorethylene?
Tetrachlorethylene, also known as tetrachloroethylene, perchloroethylene, PCE, or "perc," is a commonly used solvent (a substance, usually a liquid, capable of dissolving another substance). It has been in commercial use since the early 1900s.
A common use of tetrachlorethylene is to dry clean fabrics. It dissolves greases, oils, and waxes without affecting fabrics, which makes it useful for this purpose.
Tetrachlorethylene is also used to clean and degrease metals. Oil and wax are used to shape and polish metal during the manufacturing process. Removing oil, wax, and related substances from the finished products is known as degreasing.
It has also been used in water repellants, paint removers, printing inks, glues, sealants, polishes, and lubricants. Tetrachlorethylene is also used to make other chemicals.
How are people exposed to tetrachlorethylene?
Tetrachlorethylene is a liquid at room temperature but evaporates easily into air. When it is in the air it can condense again and get into soil and water. It can also be washed out of the air with rain. It can also get into soil and water during waste disposal, or by leaking from underground storage tanks. In the past, in certain areas, it also could get in the water by leaching out of the vinyl lining of the pipes in the water system. This is less of a concern now, because the pipes have been treated in areas where this has happened.
Tetrachlorethylene is present in very tiny amounts in the air we breathe and in the water we drink. It can also be present in very tiny amounts in soil, and less often, in food. Using a consumer product, such as a water repellent, that contains tetrachlorethylene, could also expose you to a small amount of this chemical.
People can be exposed to tetrachlorethylene by breathing it in, by direct contact with the skin, or by ingesting contaminated water or food. No matter how you are exposed to tetrachlorethylene, most of it leaves your body when you exhale. A small amount may stay behind. Some of this is changed by the body into other chemicals and then removed from the body in urine. Some stays in the body for a time.
People who live near dry cleaning or metal degreasing operations, people using coin-operated laundries where dry cleaning machines are present, and people who live in buildings where dry cleaning shops are located are exposed to higher amounts of tetrachlorethylene in the air.
The highest exposures to tetrachlorethylene tend to occur in the workplace, especially among dry cleaning and degreasing workers. Workers in some other industries may also be exposed to tetrachlorethylene.
Does tetrachlorethylene cause cancer?
Tetrachlorethylene has been suspected of causing some types of cancer, based on both human and animal evidence.
Studies in people
Studies have looked at people exposed at work and people in communities with contaminated drinking water.
Some studies of people exposed to tetrachlorethylene at work (dry cleaning workers, workers at a chemical company, and workers in aircraft maintenance) found more cases than expected of certain cancers, including cancers of the esophagus, kidney, cervix, and bladder, as well as lymphomas. However, the results of these studies did not always agree, and there were so few cases of cancer that the increased risk often may have been due to chance. Many of these studies also weren't able to account for other factors that might affect cancer risk, such as cigarette smoking or alcohol use.
Other studies have looked for a link between tetrachlorethylene in drinking water and cancer. A few studies have looked at areas of Massachusetts where some drinking water supplies were accidentally contaminated with high levels of tetrachlorethylene. (Levels in some of these areas were hundreds of times the current Environmental Protection Agency [EPA] standard of 0.005 milligrams of tetrachlorethylene per liter of water [0.005 mg/L]). These studies found evidence of an increased risk of leukemia as well as lung and bladder cancer among residents with the highest exposure to tetrachlorethylene. However, these studies often weren’t able to take other risk factors for cancer into account, so it isn’t clear how much the increased risk was from the chemical.
Studies done in the lab
Laboratory studies have found that ingesting or inhaling tetrachlorethylene increased the risk of liver cancer in mice. In rats, inhaling tetrachloethylene was linked to kidney cancer and a rare type of leukemia.
What expert agencies say
Several agencies (national and international) study different substances in the environment to determine if they can cause cancer. (A substance that causes cancer or helps cancer grow is called a carcinogen.) The American Cancer Society looks to these organizations to evaluate the risks based on evidence from laboratory, animal, and human research studies.
A few expert agencies have looked at whether tetrachlorethylene can cause cancer.
The International Agency for Research on Cancer (IARC) is part of the World Health Organization (WHO). Its major goal is to identify causes of cancer. Based on the data from studies in people and lab animals, IARC classifies tetrachlorethylene as “probably carcinogenic to humans.”
The National Toxicology Program (NTP) is formed from parts of several different US government agencies, including the National Institutes of Health (NIH), the Centers for Disease Control and Prevention (CDC), and the Food and Drug Administration (FDA). The NTP has classified tetrachlorethylene as “reasonably anticipated to be a human carcinogen.”
The US Environmental Protection Agency (EPA) maintains the Integrated Risk Information System (IRIS), an electronic database that contains information on human health effects from exposure to various substances in the environment. The EPA has classified tetrachlorethylene “likely to be carcinogenic in humans by all routes of exposure.”
(For more information on the classification systems used by these agencies, see Known and Probable Human Carcinogens.)
Does tetrachlorethylene cause any other health problems?
Tetrachlorethylene is not absorbed well through the skin, but skin contact can cause irritation.
The low levels of tetrachlorethylene that most people are exposed to in air, water, and food don’t seem to cause any symptoms.
Higher levels of tetrachlorethylene in the air can lead to irritation of the eyes, skin, nose, throat, and/or respiratory system. Other effects may include nausea, headache, dizziness, vision problems, and trouble speaking and walking. There can also be facial flushing and abnormal heartbeat. Kidney and liver damage can occur over the long term.
Very high concentrations of tetrachlorethylene (such as in a closed and poorly ventilated area) can cause worse neurologic symptoms such as confusion, drowsiness, loss of consciousness (passing out), and even coma and death.
Are tetrachlorethylene levels regulated?
Several government agencies regulate tetrachlorethylene levels and exposures.
The Occupational Safety & Health Administration (OSHA), the federal agency responsible for health and safety regulations in most workplaces, limits workplace exposure to tetrachlorethylene in the air to 100 ppm (parts per million) during an average 8-hour workday and a maximum of 300 ppm over any 5-minute period.
The EPA limits concentrations of tetrachlorethylene in drinking water to 0.005 mg/L or 5 parts per billion (ppb), with an ultimate goal of 0 ppb. Likewise, the US Food and Drug Administration (FDA) has set a limit of 5 ppb in bottled water.
Can I reduce my exposure to tetrachlorethylene?
Because of the possibility that tetrachlorethylene may cause cancer, and because it can have other health effects, you should limit your exposure as much as possible.
In the workplace
For people who work in an area with potential exposure to tetrachlorethylene, such as dry cleaning and degreasing workers, there are several ways to reduce or prevent exposure. Good work practices, such as changing clothes after work, washing work clothes regularly, and keeping food out of the work area, are essential. Depending on the potential level of exposure, personal protective equipment such as gloves and respirators may be an important part of a workplace protective program. Companies can also reduce workers' exposure through engineering changes, such as substituting safer materials for more hazardous ones, enclosing a process that may expose workers to hazards, or ventilating a work area.
For more information on preventing or reducing workplace exposure, talk to your company's safety and health manager. Additional information is available from the Occupational Safety & Health Administration (OSHA).
Workplace and environmental exposure to tetrachlorethylene used in dry cleaning shops can be reduced by using newer dry cleaning machines that control or eliminate its escape during the dry-cleaning process. New methods of fabric cleaning which use water as a solvent in specialized machines are available in some areas.
If you wear clothing that has been dry cleaned, you may be exposed to tetrachlorethylene levels that are slightly higher than what is normally found in the outdoor air, but these amounts are not expected to be hazardous to the average person's health. Professional dry cleaners remove tetrachlorethylene from dry cleaned clothes as part of the overall cleaning process. You cannot tell by odor alone if all of the tetrachlorethylene has been removed from your clothes. If you think all of the solvent was not removed, or if your newly dry cleaned clothes smell like solvent, you should ask your cleaner to re-process your order or take them to another cleaner for re-cleaning.
Public water systems must check the water supply regularly for levels of tetrachlorethylene and other possible contaminants. If routine monitoring finds that the tetrachlorethylene level is too high, the water supplier must take steps to reduce it to levels within normal limits. The supplier must also notify its customers within 30 days after finding the violation.
If your drinking water comes from a public source, you can find out about the levels of certain substances in your water by contacting your local water system. Each system is also required to provide its customers with an annual report on water quality known as a Consumer Confidence Report. This report lists the levels of certain chemicals and other substances in the water.
If your water comes from a private well, check with your local health department or water system for information about possible contaminants of concern in your area.
For more information, visit the EPA's website at http://water.epa.gov/drink/contaminants/basicinformation/tetrachloroethylene.cfm. For more general information about drinking water safety, contact the EPA's Safe Drinking Water Hotline at 1-800-426-4791.
In addition to the American Cancer Society, other sources of information and support include:
Agency for Toxic Substances and Disease Registry (ATSDR)
Toll-free number: 1-888-422-8737 (1-888-42-ATSDR)
ToxFAQs for tetrachloroethylene (PERC): www.atsdr.cdc.gov/toxfaqs/tf.asp?id=264&tid=48
Environmental Protection Agency
Toll-free number (Safe Drinking Water Hotline): 1-800-426-4791
Basic information about tetrachloroethylene in drinking water: http://water.epa.gov/drink/contaminants/basicinformation/tetrachloroethylene.cfm
Occupational Safety & Health Administration (OSHA)
Toll-free number: 1-800-321-6742 (1-800-321-OSHA)
Safety and health topics - dry cleaning: www.osha.gov/SLTC/drycleaning/index.html
*Inclusion on this list does not imply endorsement by the American Cancer Society
Agency for Toxic Substances and Disease Registry. ToxFAQs for Tetrachloroethylene (PERC). 10/17/2011. Accessed at http://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=264&tid=48 on October 16, 2013.
Agency for Toxic Substances and Disease Registry. Toxicological profile for tetrachloroethylene. September 1997. Accessed at www.atsdr.cdc.gov/toxprofiles/tp18.pdf on October 22, 2013.
Anttila A, Pukkala E, Sallmen M, et al. Cancer incidence among Finnish workers exposed to halogenated hydrocarbons. J Occup Environ Med. 1995;37:797−806.
Aschengrau A, Rogers S, Ozonoff D. Perchloroethylene-contaminated drinking water and the risk of breast cancer: additional results from Cape Cod, Massachusetts, USA. Environ Health Perspect. 2003 Feb;111(2):167-73.
Environmental Protection Agency. Design for the Environment: Frequently Asked Questions About Drycleaning. 9/24/2013. Accessed at: http://www.epa.gov/opptintr/dfe/pubs/garment/ctsa/factsheet/ctsafaq.htm on October 16, 2013.
Environmental Protection Agency. Integrated Risk Information System: Tetrachloroethylene (CASRN 127-18-4). 2012. Accessed at http://www.epa.gov/iris/toxreviews/0106tr.pdf on October 16, 2013.
International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Vol 106: Trichloroethylene, Tetrachloroethylene and Some Other Chlorinated Agents. 2013. Accessed at http://monographs.iarc.fr/ENG/Monographs/vol106/index.php on January 2, 2014.
Kloos H. Trichloroethylene, tetrachloroethylene, nitrates, and other chemicals in well water in the Fresno-Clovis Metropolitan area. Arch Environ Health. 1997;52:348-354.
Lynge E, Andersen A, Rylander L, et al. Cancer in persons working in dry cleaning in the Nordic countries. Environ Health Perspect. 2006;114:213-219.
McDermott MJ, Mazor KA, Shost SJ, et al. Tetrachloroethylene (PCE, Perc) levels in residential dry cleaner buildings in diverse communities in New York City. Environ Health Perspect. 2005; 113:1336-43.
McLaughlin J, Blot WJ. A critical review of epidemiology studies of trichloroethylene and perchloroethylene and risk of renal-cell cancer. Int Arch Occup Environ Health. 1997;70;222-231.
Paulu C, Aschengrau A, Ozonoff D. Tetrachloroethylene-contaminated drinking water in Massachusetts and the risk of colon-rectum, lung, and other cancers. Environ Health Perspect. 1999 Apr;107(4):265-71.
US Department of Health and Human Services. Public Health Service, National Toxicology Program. Report on Carcinogens, 12th Edition. 2011. Accessed at http://ntp-server.niehs.nih.gov/ntp/roc/twelfth/profiles/Tetrachloroethylene.pdf on October 16, 2013.
Vaughan TL, Stewart PA, Davis S, et al. Work in dry cleaning and the incidence of cancer of the oral cavity, larynx, and oesophagus. Occup Environ Med. 1997;54:692-695.
Last Medical Review: January 6, 2014 Last Revised: January 6, 2014