Formation of Trifluoroacetic Acid from the Atmospheric Degradation of Hydrofluorocarbon 134a: A Human Health Concern?

Recognition of the adverse effect of chlorofluorocarbon (CFC) release into the atmosphere has led to an international effort to replace CFCs with environmentally acceptable alternatives.1 " 3 Hydrofluorocarbon 134a (1,1,1,2-tetrafluoroethane) is a potential substitute for CFC-12 which is used in automotive air conditioning systems.In March 1992, Ford Motor Company was the first U.S. manufacturer to start production of automobiles with HFC-134a refrigerant.Because of the anticipated large scale industrial use of HFC-134a, the environmental consequences of its release into the atmosphere need to be evaluated.Concern has been raised regarding the potential atmospheric transformation of HFC-134a into trifluoroacetic acid, CF 3 COOH, and the impact this might have upon human health.The analogous chlorinated compound, trichloroacetic acid, CC1 3 COOH, is a known liver carcinogen.Clearly, the potential for trifluoroacetic acid formation in the atmosphere, and the impact of this compound on human health need consideration.To resolve this issue we need to answer two questions.First, "What levels of CF 3 COOH are expected in the environment due to the use of HFC-134a?" and second, "Are these levels of concern for human health?"We address both questions here.