CFCs and halons, types of refrigerants, harm the ozone layer. The Montreal Protocol was created in 1987 by the United Nations and 22 countries to ban ozone-depleting compounds (DCs) like CFCs. Over 70 countries are part of this agreement. Initially, CFC use was frozen at 1986 levels, with plans to reduce them by 50% in 1998. Due to increasing ozone depletion, the protocol was updated in 1992 to reduce CFC production by 75% by 1994, eventually phasing them out by 1996.