Fluorocarbons containing chlorine or bromine have been associated with
stratospheric ozone depletion and the search for suitable alternative
s is progressing at an accelerated pace. The Program for Alternative F
luorocarbon Toxicity Testing (PAFT), an international group representi
ng most of the world's CFC producers, has been conducting comprehensiv
e toxicological evaluations on several possible replacements for curre
nt fire-extinguishing agents - 1,1-dichloro-2,2,2-trifluoroethane (HCF
C-123), 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124), pentafluoroetha
ne (HFC-125), and 1-fluoro-2,2,2-trifluoroethane (HFC-134a). Results f
rom short-term experimental studies showing a low order of acute toxic
ity, as well as results from longer-term toxicity studies on these rep
lacements, will be discussed.