Learn about EPA's efforts to address ozone layer depletion through international treaties and initiatives. The Montreal Protocol is an international agreement made in 1987.It was designed to stop the production and import of ozone depleting substances. This important UN treaty offsite link bans the release of harmful ozonedepleting chemicals such as chlorofluorocarbons, or CFCs. This page summarizes the history of international cooperation on the protection of the ozone layer, including: the Vienna Convention; the Montreal Protocol. Bankobeza (former Chief of. Legal Affairs and Compliance, Ozone Secretariat, United Nations Environment Programme).