Evaluates the environmental behaviour, toxicity, and ozone-depleting and global-warming potentials of six partially halogenated ethane derivatives selected as candidates to replace the fifteen fully halogenated chlorofluorocarbons that are being phased out in line with the provisions of the Montreal Protocol on Substances that Deplete the Ozone Layer. The compounds considered are 1,1-dichloro-1-fluoroethane (HCFC 141b), 1-chloro1,1-difluoroethane (HCFC 142b), 1,2-dichloro-1,1-difluoroethane (HCFC 132b), 1-chloro-2,2,2-trifluoroethane (HCFC 133a), 1,1-dichloro-2,2,2-trifluoroethane (HCFC 123), and 1-chloro-1,2,2,2-tetrafluoroethane (HCFC 124). All compounds were judged to have ozone-depleting and global-warming potentials considerably lower than those of CFC 11, the fully halogenated chlorofluorocarbon with the highest ozone-depleting and global-warming potentials. Estimated atmospheric lifetimes range from 1.6 years for HCFC 123 to 19.1 years for HCFC 142b. Because studies of HCFC 132b and HCFC 133a have documented a number of toxic effects, these compounds could not be recommended as substitutes. Since the toxicity of HCFC 142b is low and the ozone-depleting and global-warming potentials are lower than those of the fully halogeated chlorofluorocarbons, the report concludes that HCFC 142b can be considered as a transient substitute for the chlorofluorocarbons included in the Montreal Protocol. In view of the paucity of toxicological data on HCFC 141b, HCFC 123, and HCFC 125, no evaluation of their potential effects on human health could be made.

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WHODOC

WHO monograph

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