| Ninety-six (96) chemicals are presently controlled by the Montreal Protocol, including: • Halo-carbons, notably chlorofluorocarbons (CFCs) and Halons. CFCs were discovered in 1928 and were considered wonder gases because they are long-lived, non-toxic, non-corrosive, and non-flammable. They are also versatile and from the 1960s were increasingly used in refrigerators, air conditioners, spray cans, solvents, foams, and other applications. CFC-11 remains in the atmosphere for 50 years, CFC-12 for 102 years, and CFC-115 for 1,700. Halon 1301 is used primarily in fire extinguishers and has an atmospheric lifetime of 65 years. • Carbon tetrachloride is used as a solvent and takes about 42 years to break down in the atmosphere. • Methyl chloroform (1,1,1-trichloroethane) is also used as a solvent and takes about 5.4 years to break down. • Hydrobromofluorocarbons (HBFCs) are not widely used, but they have been included under the Protocol to prevent any new uses. • Hydrochlorofluorocarbons (HCFCs) were developed as the first major replacement for CFCs. While much less destructive than CFCs, HCFCs also contribute to ozone depletion. They have an atmospheric lifetime of about 1.4 to 19.5 years. • Methyl bromide (CH3Br) is used as a fumigant for high-value crops, pest control, and quarantine treatment of agricultural commodities awaiting export. Total world annual consumption is about 70,000 tonnes, most of it in the industrialized countries. It takes about 0.7 years to break down. • Bromochloromethane (BCM), a new ozone-depleting substance that some companies sought to introduce into the market in 1998, has been targeted by the 1999 Amendment for immediate phase-out to prevent its use. • The Parties are considering measures to prevent the marketing of new ozone-depleting substances not so far covered by the Protocol.
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