Protecting the stratospheric ozone layer by controlling the production and use of ozone-depleting compounds has been an environmental concern since the mid-1970s, when it was discovered that chlorine could potentially deplete the ozone layer. Not until significant losses of ozone were reported in 1985, however, did ozone depletion become an important international issue. The principal international policy instrument for protecting the stratospheric ozone layer is the Montreal Protocol on Substances That Deplete the Ozone Layer. Many countries, and even some cities and other subnational authorities, have taken action to control production and use of chlorofluorocarbons (CFCs) and other ozone-depleting substances. Much of the National/Subnational Ozone Policy Formulation is in response to the Montreal Protocol, although several countries had taken steps to control CFCs prior to the international agreements set forth in the Protocol.
In response to these policy and regulatory developments, industrial organizations directly affected have been actively engaged in developing alternative substances to CFCs and other ozone-depleting compounds. Several environmental and economic factors need to be considered in Chlorofluorocarbon Phaseout, such as safety characteristics, efficiency, ozone-depletion potential, and economic impacts on industry of phaseout schedules for existing CFCs.