According to the New York State Department of Environmental Conservation (NYSDEC), there are about 2,000 dry cleaning facilities in New York state that use perchloroethylene (“perc”) as the solvent in their dry cleaning machines. Most of these facilities are located within the New York City metropolitan area.

Twenty years ago, in 1997, the NYSDEC enacted a regulation aimed at minimizing the public's exposure to perc vapors by reducing and controlling releases of perc from dry cleaning establishments. The regulation deals with design and performance standards for dry cleaning machines, ventilation standards, operation and maintenance requirements, and operator training and certification. The regulation has deadlines for replacing older, outdated machines that are more pollution-prone with modern machines (so-called fourth generation machines) that employ vapor protection devices to prevent perc from migrating from the machines into adjacent spaces or the ambient air.

Although the regulation encourages dry cleaners to switch to alternate solvents, the NYSDEC reports that about 70 percent of the dry cleaners located in the state still use perc as their solvent of choice. This is because perc has good cleaning properties, is nonflammable, and is cost effective.