2. Relevance to Public Health 2.1 Background and Environmental Exposures to 1,1,1-trichloroethane in the United States

1,1,1-Trichloroethane is a synthetic chemical. In 2003, the estimated capacity of the commercial production of 1,1,1-trichloroethane in the United States was 510 million pounds. Under the Clean Air Act as amended in 1990, all production of 1,1,1-trichloroethane for domestic use was scheduled to cease as of January 1, 2002. It may be used for essential applications such as medical devices and aviation safety (for the testing of metal fatigue and corrosion of existing airplane engines and other parts susceptible to corrosion) until January 1, 2005 or for export to developing countries until January 1, 2012. 1,1,1-Trichloroethane was predominantly used as a chemical intermediate in the manufacture of hydrochlorofluorocarbons (HCFCs). It was also commonly used in vapor degreasing and cold cleaning, adhesives, coatings and inks, textiles, and electronics. Currently, 1,1,1-trichloroethane is almost entirely used as a precursor for hydrofluorocarbons.