A group of brominated organic compounds used as fire retardants, including CF3Br (halon 1301), CF2Br2 (halon 1202), CF2BrCl (halon 1211), and CF2BrCF2Br (halon 2402). The transport of these compounds to the stratosphere, followed by their photolysis to release Br atoms, gives this group a very high ozone depletion potential. The production of these compounds is now banned as a result of the Montreal Protocol and its subsequent amendments.