In what environmentalists are calling tremendous opportunity to protect the Earth's ozone a new agreement between automobile manufacturers and the Environmental Protection Agency has cleared the way for recycling of the chlorofluorocarbon (CFC) refrigerant used in auto and truck air conditioners. Releases of CFC-12 (CCI 2 F 2 ) from mobile air conditioners are currently the largest single source of ozone-destroying CFC emissions in the U.S. CFC-12 is one of the eight fully halogenated chlorofluorocarbons whose production is being regulated in an attempt to halt depletion of the ozone layer, which shields Earth's surface from harmful ultraviolet radiation. Starting in July, EPA regulations will freeze U.S. production of the chemicals at 1986 levels. By 1998, output must be cut to 50% of 1986's production, in accordance with an international treaty that went into effect Jan. 1. Most of the CFC-12 used in truck and car air conditioners—about 54,000 metric tons in 1985—is ...