The short answer
Tetrachloroethylene, or 'perc,' is the main dry-cleaning solvent. Workplace exposure is classified as probably carcinogenic, with a suspected link to bladder cancer. Modern equipment and alternatives reduce exposure.
Tetrachloroethylene is classified as a probable human carcinogen (IARC Group 2A).
People are mainly exposed by breathing vapors at work or near dry-cleaning facilities.
It is most strongly linked to a suspected link to bladder cancer.
A carcinogen classification describes hazard — whether something can cause cancer — not your personal risk at a given exposure.
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The full explanation.
The simple version
Tetrachloroethylene, often called perc, is the chemical most used in dry cleaning. Dry-cleaning workers and people near some facilities have the most exposure. It is classified as a probable carcinogen. Airing out freshly dry-cleaned clothes reduces the small amount you breathe at home.
What tetrachloroethylene is
Tetrachloroethylene (perchloroethylene, or perc) is a solvent used in dry cleaning and metal degreasing. It can enter indoor air and, near some sites, groundwater. IARC classifies it as probably carcinogenic; the EPA also identifies cancer concerns and has acted to restrict some uses.
How people are exposed
Common ways people come into contact with it:
- Working in dry cleaning or metal degreasing
- Living near dry cleaners or contaminated sites
- Breathing vapors from freshly dry-cleaned clothes (small amounts)
The cancer connection
Tetrachloroethylene is linked most closely to bladder cancer, with possible associations to non-Hodgkin lymphoma. Human evidence is limited.
The International Agency for Research on Cancer (IARC), the cancer arm of the World Health Organization, places tetrachloroethylene in Group 2A, probably carcinogenic to humans — meaning the evidence in people is limited but there is strong support from animal or mechanistic studies. In the United States, the National Toxicology Program's Report on Carcinogens lists it as reasonably anticipated to be a human carcinogen.
Hazard is not the same as risk
It helps to separate two ideas that are easy to mix up: hazard and risk. When an agency lists tetrachloroethylene as a carcinogen, it is making a statement about hazard — whether the substance is capable of causing cancer under some conditions. It is not, by itself, a statement about your personal risk, which depends on how much you are exposed to, for how long, and other factors. Two substances in the same group can carry very different real-world risks. The label answers "can it cause cancer?" — not "how likely is it to cause cancer for me?"
How to lower your exposure
- Air out freshly dry-cleaned clothes before wearing or storing them
- Choose 'wet cleaning' or perc-free cleaners where available
- Rely on modern closed-loop dry-cleaning equipment and workplace limits
If you are looking at your overall cancer risk, small, steady steps add up. See our overview of cancer prevention and what raises cancer risk to put any single exposure in context.
The bottom line
Tetrachloroethylene is a probable human carcinogen (IARC Group 2A). The most important thing you can do is understand where exposure comes from and take reasonable steps to reduce it, without losing sleep over a single label. Focus your energy on the biggest, most controllable risks in your own life.
Words to know
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Common questions
▸Does tetrachloroethylene cause cancer?
Probably. Tetrachloroethylene is classified as a probable human carcinogen: the evidence in people is limited, but animal and laboratory studies support a link. "Probable" means suspected on solid grounds, not proven.
▸How are people exposed to tetrachloroethylene?
Most exposure happens by breathing vapors at work or near dry-cleaning facilities.
▸Which cancers are linked to tetrachloroethylene?
It is most strongly linked to a suspected link to bladder cancer.
▸How can I reduce my exposure to tetrachloroethylene?
The main steps are airing out dry-cleaned clothes and using perc-free options.
▸Does a carcinogen label mean I will get cancer?
No. A classification is about hazard — whether tetrachloroethylene can cause cancer under some conditions — not a prediction that any one exposed person will develop cancer. Your actual risk depends on the amount and length of exposure and other factors.
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