Chemical formula CBrClF₂ Synonyms: Halon 1211, Freon 12B1, chlorodifluorobromomethane. This chemical belongs to the freon family. Halon 1211 was introduced in the 1960s as an effective gaseous fire suppression agent for application in the protection of computer control rooms, museums, telecommunication switches and other areas containing highly valuable materials. Results of studies done in the late 1980s indicated that the agent was an ozone depleting chemical. This chemical is stable in the troposphere but photodissociates to yield halogen radicals in the upper atmosphere, which can catalytically destroy stratospheric ozone.