By international agreement, however, production of all types of halons ceased in 1994 because the bromine and chlorine atoms in the chemical were found to migrate over time to the stratosphere, where they react to deplete ozone in a very efficient catalytic cycle. (scientificamerican.com)
Indeed, bromine and chlorine atoms are released as halons decompose in the heat of the fire, establishing a catalytic cycle involving HBr and HCl; the cycle converts active hydrogen atoms to stable H2 molecules, breaking the chain reaction. (scientificamerican.com)
Beginning in 1987, the internationally agreed - upon Montreal Protocol on Substances that Deplete the Ozone Layer has regulated these ozone - depleting compounds, such as chlorine - containing chlorofluorocarbons used in refrigerants and bromine - containing halon gases used as fire suppressants. (sciencedaily.com)