Dry cleaning solvent (perc) and cancer: what EPA says

This page is for anyone wondering whether dry cleaning chemicals cause cancer, including people who work in dry cleaning. It covers what the EPA says and who the evidence applies to.

That sharp smell on a freshly cleaned suit usually comes from tetrachloroethylene. Almost everyone in the trade calls it perc. The EPA lists its uses:

• Dry cleaning and textile processing
• As a chemical intermediate, meaning a building block for other chemicals
• Vapour degreasing, when metal parts are cleaned

So this is a real industrial solvent.

The EPA's classification is direct. Perc is likely to be carcinogenic to humans by all routes of exposure. Carcinogenic means cancer-causing.

The EPA says this rests on two kinds of evidence. Studies in people gave suggestive evidence. Animal studies gave conclusive evidence. Rats developed mononuclear cell leukemia. Mice showed more liver tumours.

There is human data as well. Studies looked at dry cleaning workers exposed to perc. They found links between exposure and bladder cancer, non-Hodgkin lymphoma, and multiple myeloma.

EPA classifies perc as likely to be carcinogenic to humans. The human evidence comes from workplace studies.

Read that last section again and watch the subject of the sentence. It is workers.

The human evidence comes from people who spent their working days near the solvent. Many did so for years. They worked in rooms where it evaporated all day long.

That is not the same as carrying a garment bag home once a month. The EPA fact sheet says its cancer evidence comes from workplace studies. It gives no estimate for a customer who drops off clothes now and then. So we cannot give you one either.

The EPA's indoor air pages do give one clear piece of advice for shoppers. If dry-cleaned goods have a strong chemical odour when you pick them up, do not accept them until they have been properly dried. If items keep coming back smelling of solvent, EPA suggests trying a different dry cleaner.

Cancer tends to crowd out everything else. But perc's other effects are well described.

Short, high exposures can irritate the upper airway and the eyes. They can disturb how the kidneys work. At lower levels they can cause mood and behaviour changes that go away afterward. They can also cause poor coordination, dizziness, headache, sleepiness, and unconsciousness.

Breathing it in over a long period mainly affects the nervous system. That includes headaches. It also includes trouble with thinking and movement, and reduced colour vision.

The EPA fact sheet also notes that newer dry cleaning methods have substantially reduced workplace exposure.

• Send back any item that arrives with a heavy solvent smell, and wait until it has been properly dried.
• If you work in dry cleaning, or used to, say so when a clinician takes your history. Job details are easy to leave out and hard to rebuild later.
• If you work around the solvent now, ask about ventilation and equipment upkeep.

Some people read a page like this after a cancer diagnosis and start to wonder about an old job. That is understandable.

But no page can tell you whether perc caused your illness. A link across a group of workers is not proof of cause in one person.

Bring the history to your team. Let them decide what belongs in your notes. Then try not to spend your recovery putting the past on trial.

• EPA — Tetrachloroethylene (Perchloroethylene) Fact Sheet
• EPA — Volatile Organic Compounds' Impact on Indoor Air Quality