Smarter Living: Chemical Index

Used to dry-clean clothes, perchloroethylene (PERC) is a danger not only to dry-cleaning workers but also consumers who bring dry-cleaned clothes into their homes.

What Is It?

PERC is a chemical solvent used to dry clean clothes. It readily evaporates into air and has a strong, sweet odor. PERC is also used in paint strippers, spot removers, and other solvent-based household products. It is not to be confused with perchlorate, a rocket fuel ingredient that contaminates water supplies.

Health Concerns

PERC can harm the brain and central nervous system, damage the liver and kidneys, and is likely to cause cancer.

Of these health concerns, the best documented is PERC’s damage to the nervous system and brain. Breathing low levels of PERC can cause people to experience dizziness, sleepiness, headaches, and nausea. Inhaling large amounts of the chemical can cause people to pass out and very high amounts can be fatal. Long term or chronic exposure to PERC, even at low doses, can lead to permanent harm, including brain effects such as loss of short term memory and concentration, or central nervous system effects such as loss of muscle coordination.

Several workplace studies reported elevated risks of esophageal cancer, non-Hodgkin’s lymphoma, and cervical cancer in people exposed occupationally. PERC is linked to cancers in rodent studies, including leukemia, liver, and kidney cancer. The U.S. National Toxicology Program lists PERC as “may reasonably be anticipated to be a human carcinogen” in the Report on Carcinogens. The International Agency for Research on Cancer (IARC) lists it as “probably carcinogenic to humans.”


PERC lingers in recently dry-cleaned clothing and slowly escapes into your car and home. It is characterized by a sharp, sweet odor. PERC has been detected in apartments above dry-cleaning facilities.

The chemical may also be found in consumer products such as adhesives, spot removers, correction fluid, and wood cleaners. You may also come into contact with PERC if you work in an industry that produces chemicals or rubber coatings, degreases metal tools, or makes textiles.

Because PERC has been widely used in dry-cleaning facilities and other industries throughout towns and cities, and because business owners sometimes dumped PERC into sewer systems or backyards, drinking water contamination may be a concern in some water supplies. The federal Safe Drinking Water Act requires municipal water systems to monitor for PERC and keep levels low, but people who drink water from wells should have their water tested if they suspect contamination.

Stay Safe

One of the easiest ways to avoid PERC is by choosing alternatives to dry-cleaning your clothes. Be aware, however, that some non-PERC dry-cleaners use alternatives, sometimes called “hydrocarbon” treatments, that are also toxic.

Instead of dry-cleaning, look for stores that advertise wet-cleaning, an alternative form of washing and drying that is safe for most clothing. Another good option, but less available, is CO2 cleaning, which uses liquid carbon dioxide to clean clothes. Check the Pollution Control Center site at Occidental College for wet-cleaners and CO2 cleaners near you. Another resource is the National Clearing House for Professional Wet Cleaners.

Airing out recently dry-cleaned clothes can reduce your family’s exposure to PERC, but it doesn’t help reduce the use of this toxic chemical. If you cannot find a professional alternative to dry-cleaning, consider handwashing your garments in cold water. Many items can be safely washed even when the label says Dry Clean.

Take Action

Get involved with local, state, and federal efforts to regulate or ban PERC in dry cleaning. Such efforts have already been successful in California, which has enacted a ban that requires dry cleaners to phase in alternative technologies over the next several years.

Learn More

ATSDR Agency for Toxic Substances and Disease Registry ToxFAQs (1997).(PDF)

IARC Monograph on the Evaluation of Carcinogenic Risks to Humans. Tetrachloroethylene. Vol 63 (1995) p. 159-205 (PDF)

12TH Report on Carcinogens. National Toxicology Program. (2005)

last revised 12/27/2011

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