If you've ever dry cleaned your clothes (you have, right?), you've likely wondered how the "dry" part happens. And it may even have crossed your mind that it's a chemical process. Of course you'd be right.
Dry cleaners use dangerous chemical solvents that can stick to clothing. Most cleaners use perchloroethylene, also known as tetrachloroethylene, PCE, or perc. It is reasonably anticipated to be a human carcinogen, according to the U.S. National Toxicology Program, a prestigious inter-agency scientific body. The International Agency for Research on Cancer has reached a similar conclusion.
When inhaled, even low concentrations of perc are known to cause respiratory and eye irritation, headache, dizziness and vision problems.
How much perc remains on dry cleaned clothing?
A new study by scientists at Georgetown University, published online last month in the journal Environmental Toxicology and Chemistry, found high levels of residual perc on dry-cleaned wool, cotton and polyester (what do you have on now?). Subsequent dry cleaning cycles intensified these concentrations. Silk was the only fabric that did not appear to retain perc.
The research team found that the concentration of the chemical on wool was reduced by about half after a week, even inside a plastic bag. This finding suggests that perc vaporizes from clothing and is released into your home.
The Georgetown study was the first of its kind. "I was surprised that no one has taken this first step of quantifying perchloroethylene," says Paul Roepe, the principal author. "There should be a lot more studies done on this."
Roepe noted that actual human exposure and the consequent health effects from the amounts of perc his team found on fabrics are difficult to assess. Nevertheless, the presence of a suspected carcinogen and its inherent capacity to dissipate into the air are disconcerting. Dry cleaning workers face even greater hazards than consumers.
There are no federal regulations that limit the use of perc in commercial dry cleaning, but the U.S. Environmental Protection Agency is reassessing the chemical's health impacts.
The California Environmental Protection Agency has adopted measures to phase the chemical out of dry cleaning by 2023.
Dry cleaning establishments have begun using alternatives to perc. In fact, fabrics cleaned at dry cleaners in the Georgetown study successfully used so-called "green" methods that left no perc residue.
However, consumers should always be wary of substitutes. The dry cleaning solvent Siloxane D5, for instance, has a potential cancer hazard and accumulates in human and animal bodies and the environment. There is some evidence that hydrocarbon dry cleaning fluid, which typically employs a propriety mixture of chemicals, causes cancer in rats. Georgetown researchers say that one of the "green" dry cleaners from which they obtained samples most likely used hydrocarbon solvents.
There are very few truly "green" dry cleaning technologies. Liquid carbon dioxide is the safest because it uses a naturally occurring gas and recyclable cleaning agents. Another safe alternative is wetcleaning, a relatively new process that uses biodegradable detergents and water.
The best way to avoid harmful dry cleaning chemicals is to buy washable clothing. When you must dry clean, follow these tips:
- Ask your cleaners what solvents they use. Watch out for perchloroethylene under any of its names (perc, PCE, tetrachloroethylene), siloxane and hydrocarbon solvents.
- Patronize cleaners that use liquid carbon dioxide or the wetcleaning method.
If your only option is a dry cleaner that uses perc:
- Don't leave dry cleaned items in the car for a long time because perc vapors can build up inside the vehicle.
- Air dry cleaned clothes outdoors.
- Ask for a less toxic alternative - you just might convince them.