Tetrachlorethylene (Perchloroethylene)

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.

Tetrachlorethylene is the most common cleaning fluid used in dry cleaning. It dissolves greases, oils, and waxes without affecting fabrics, which makes it useful for this purpose.

Tetrachlorethylene is also used to 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. In the past, tetrachlorethylene was used to make chlorofluorocarbons (refrigerants), although this use has largely been phased out because of their effects on the ozone layer.

How are people exposed to tetrachlorethylene?

People can be exposed to tetrachlorethylene by breathing in vapors, by direct contact with the skin, or by ingesting contaminated water or food.

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.

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 can breathe in smaller amounts from time to time. People who live in communities that have drinking water contaminated by tetrachlorethylene can drink it, or inhale it while bathing or showering.

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 dry cleaning workers with exposure to tetrachlorethylene have found possible increased risks of cancers of the esophagus, larynx (voice box), cervix, and lungs, as well as lymphomas. However, the results of these studies have to be viewed cautiously because many of them weren't able to account for behavioral 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 tetrachloroethylene per liter of water [0.005 mg/L]). These studies found evidence of a possible increase in risk of lung, breast, and colorectal cancer among residents with the highest exposure to tetrachlorethylene. However, some other studies have not found such a link.

Studies done in the lab

Laboratory studies have found that tetrachlorethylene increased the risk of liver cancer when high levels were ingested or inhaled by lab mice, and raised the risk of a rare type of leukemia when inhaled by a certain strain of rat.

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 not officially classified tetrachlorethylene as to its carcinogenicity.

(For more information on the classification systems used by these agencies, see our document, Known and Probable Human Carcinogens.)

Does tetrachlorethylene cause any other health problems?

Short-term exposure to tetrachlorethylene may irritate the eyes, skin, nose, throat, and/or respiratory system. Other effects may include nausea, facial flushing, abnormal heartbeat, and kidney and liver damage.

Tetrachlorethylene may also affect the nervous system. High doses cause headache, dizziness, visual disturbances, lack of coordination, drowsiness, numbness and tingling, fainting spells, hallucinations, 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 use of 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.

Dry-cleaned clothes

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 perchloroethylene from dry cleaned clothes as part of the overall cleaning process. You cannot tell by odor alone if all of the tetrachloroethylene 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.

Water supplies

Public water systems must check the water supply regularly for levels of tetrachlorethylene and other possible contaminants. If routine monitoring finds that the tetrachloroethylene 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 Web site at www.epa.gov/safewater/contaminants/basicinformation/tetrachloroethylene.html. For more general information about drinking water safety, contact the EPA's Safe Drinking Water Hotline at 1-800-426-4791.

Additional resources

More information from your American Cancer Society

The following related information may also be helpful to you. These materials may be viewed on our Web site or ordered from our toll-free number, at 1-800-227-2345.

Known and Probable Human Carcinogens

National organizations and Web sites*

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)
Web site : www.atsdr.cdc.gov

ToxFAQs for tetrachloroethylene (PERC): www.atsdr.cdc.gov/tfacts18.html

Environmental Protection Agency
Toll-free number (Safe Drinking Water Hotline): 1-800-426-4791
Web site : www.epa.gov

Basic information about tetrachloroethylene in drinking water: www.epa.gov/safewater/contaminants/basicinformation/tetrachloroethylene.html

Occupational Safety & Health Administration (OSHA)
Toll-free number: 1-800-321-6742 (1-800-321-OSHA)
Web site : www.osha.gov

Safety and health topics - dry cleaning: www.osha.gov/SLTC/drycleaning/index.html

No matter who you are, we can help. Contact us anytime, day or night, for information and support. Call us at 1-800-227-2345 or visit www.cancer.org.

References

Agency for Toxic Substances and Disease Registry. ToxFAQs for Tetrachloroethylene (PERC). 2010. Accessed at www.atsdr.cdc.gov/tfacts18.html on March 16, 2010.

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, Paulu C, Ozonoff D. Tetrachloroethylene-contaminated drinking water and the risk of breast cancer. Environ Health Perspect. 1998;106 Suppl 4:947−953.

Aschengrau A, Paulu C, Ozonoff D. Tetrachloroethylene-contaminated drinking water in Massachusetts and the risk of colon-rectum, lung, and other cancers. Environ Health Perspect. 1999;107:265−271.

Environmental Protection Agency. Design for the Environment: Frequently Asked Questions About Drycleaning. 2010. Available at: www.epa.gov/opptintr/dfe/pubs/garment/ctsa/factsheet/ctsafaq.htm. Accessed March 16, 2010.

Environmental Protection Agency. Integrated Risk Information System: Tetrachloroethylene (CASRN 127-18-4). 2010. Accessed at www.epa.gov/ncea/iris/subst/0106.htm on March 8, 2010.

International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Vol 63: Dry Cleaning, Some Chlorinated Solvents and Other Industrial Chemicals. 1995. Accessed at http://monographs.iarc.fr/ENG/Monographs/vol63/index.php on March 8, 2010.

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.

US Department of Health and Human Services. Public Health Service, National Toxicology Program. Report on Carcinogens, Eleventh Edition. 2005. Accessed at http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s169tetr.pdf on March 8, 2010.

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.