Dry cleaning is the use of solvents instead of water to clean fabrics. It is believed to have originated in France in 1828 when a factory worker spilled lamp oil, a flammable petroleum-based solvent, on a soiled tablecloth. When the tablecloth dried, the spots had disappeared. The original solvents used in the dry cleaning industry included turpentine, kerosene, benzene, and gasoline. These are extremely flammable, often resulting in fires and explosions. Around 1900, scientists developed chlorinated hydrocarbons, which are nonflammable solvents. Initially, carbon tetra chloride was the preferred solvent, but because of its toxicity, it was eventually replaced by tetrachloroethylene, also known as perchloroethylene (PERC).

PERC is a colorless, clear, heavy liquid used by 90 percent of dry cleaners in the United States. Because of its significant adverse health effects, the government has imposed regulations for the control of PERC exposures and emissions. In addition to PERC, other compounds...