CFSs AND HCFCs -- Refrigerant relatives

CFCs and halons, another type of refrigerant, have been implicated as a primary cause in depletion of the stratospheric ozone, which protects the Earth from harmful ultraviolet radiation. The United Nations Environment Program and 22 countries in 1987 created the Montreal Protocol on Substances That Deplete the Ozone Layer to phase out use of ozone-depleting compounds (DCs), particularly CFCs. More than 70 countries representing 90% of the world's use of these compounds participate in the treaty. The original agreement called for a freeze at 1986 levels in the production and consumption of certain CFCs (11, 12, 113, 114 and 115), and Halon 1211, 1301 and 2402, as well as a CFC reduction to 50% of 1986 levels by 1998. In response to scientific evidence of increase stratospheric ozone depletion, however, the participating countries amended the Montreal protocol. The most recent changes occurred in late 1992, requiring reductions in CFC production to 75% of 1986 levels by Jan. 1, 1994, and a phaseout by Jan. 1, 1996.