Perchloroethylene (or “perc”) remains by far the most common drycleaning solvent used nationwide. But because it can be a hazardous air pollutant, and because it is a likely human carcinogen, California has taken steps to phase it out. Beginning in 2008, no new machines that used perc could be put into use. In July 2010, drycleaning shops located in residential buildings or near sensitive populations (such as nursing homes or daycare centers) had to stop using perc-based machines altogether, as did cleaners that used machines more than 15 years old. Finally, beginning in 2023, drycleaners in California won’t be allowed to use perc-based machines at all.

As cleaners replace old equipment, many are turning to hydrocarbon-based solvents. But even though some shops tout them as “organic” products, hydrocarbon-based solvents are not exactly green alternatives. They are volatile organic compounds (VOCs) that contribute to smog and produce hazardous waste that, like perc, needs to be carefully controlled and captured.

Another alternative to perc is machines that use liquid silicone, which is a process and solvent marketed as GreenEarth. Liquid silicone is a clear and odorless liquid similar to the basic ingredients used in underarm deodorants, cosmetics, and shaving lotions. But it might not be safe: While unlike perc and hydrocarbon-based solvents GreenEarth won’t pollute the air, the California Office of Environmental Health Hazard Assessment found that it causes uterine tumors in rats. When introduced in 2000, this technique struggled to clean as well as perc, but several reformulations have greatly improved its performance.

If you’re looking for a drycleaner that for sure uses safe, environmentally friendly cleaning methods and solvents, you have a few options:

  • “Wet-cleaning,” a non-toxic water-based cleaning method, has been used by many drycleaners for years, and so far is the most common replacement for perc-based machines. This process basically involves a high-tech washing machine that works in conjunction with stretching devices that help garments retain their size and shape.
  • The CO2 method uses liquid carbon dioxide combined with a detergent. Although liquid carbon dioxide has little environmental impact—the carbon dioxide itself is recycled from other industrial uses—due to the high cost of equipment, very few shops have adopted this method.

Many shops position themselves as “green” cleaners, but, as you can see, often these claims are overblown. Although cleaners that use hydrocarbon-based solvents are probably doing better by the Earth and your health than those using perc, it’s not as if they’re really green do-gooders. Silicone/GreenEarth is environmentally friendly, but the cancer-in-rats thing is probably a concern for most of us.