Chlorofluorocarbons (CFCs) CFCs are a family of man-made gases used for various industrial purposes. First developed in the 1920's in the United States, CFCs have been used in large quantaties since 1950. The industrialized countries can account for over 80% of CFCs use. CFC-11 is used primarily as a propellant in aerosol cans, although its use has been phased out it is still used in the production of plastic foams. CFC-12 is used in foam production as well as cooling coals of refrigerators and air conditioners. HCFC-22 was recently introduced as a replacement for CFC-12 because of its shorter life in the atmosphere, and thus is le