1,1,1,2-Tetrafluoroethane. International Chemical Assessment Document, No. 11. 1998.

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1,1,1,2-Tetrafluoroethane. Concise International Chemical Assessment Document, No. 11. 1998.

http://www.who.int/pcs/cicad/summaries/cicad_11.htm

EXECUTIVE SUMMARY

This CICAD on 1,1,1,2-tetrafluoroethane was based on a review of human health concerns (primarily occupational) prepared by the United Kingdom Health and Safety Executive in 1995 (Standring et al., 1995). Additional information on effects on human health and the environment was identified in ECETOC (1995). Data identified up to December 1994 were covered by these reviews. Additional data identified after these reviews were published have been incorporated as appropriate. Information on the nature of the peer review and availability of the source document is presented in Appendix 1. Information on the peer review of this CICAD is presented in Appendix 2. This CICAD was approved as an international assessment at a meeting of the Final Review Board, held in Berlin, Germany, on 26–28 November 1997. Participants at the Final Review Board meeting are listed in Appendix 3. The International Chemical Safety Card (ICSC 1281) for 1,1,1,2-tetrafluoroethane, produced by the International Programme on Chemical Safety (IPCS, 1998), has also been reproduced in this document.

1,1,1,2-Tetrafluoroethane (CAS no. 811-97-2) is a gaseous fluorocarbon that is manufactured by the reaction of hydrogen fluoride with trichloroethylene in a closed system. It is used primarily as a refrigerant for "high-temperature" refrigeration, such as domestic refrigerators and automobile air conditioners. Other potential uses include application in plastic foam blowing, as a solvent for special cleaning applications, as an aerosol propellant for medical inhalers, and as a fire extinguishant in place of halons.

Little information was identified on exposure of the general public or workers to 1,1,1,2-tetrafluoroethane. During its manufacture in the United Kingdom, employee exposure to the chemical was very low, with no measured concentrations above 7 ppm (29.2 mg/m³). There are no exposure measurements from its use in the manufacturing industry and no data on the exposure of field servicing personnel. The situation in the workplace in the United Kingdom and analogous data from a single study of exposure to dichlorotrifluoroethane (HCFC 123) would suggest that exposure to 1,1,1,2-tetrafluoroethane in the workplace is normally low (i.e., below 10 ppm [41.7 mg/m³]), with occasional short-term peak exposures of up to several hundred parts per million.

Information on the effects of 1,1,1,2-tetrafluoroethane on humans is limited to one report; most available data on the toxicological effects of 1,1,1,2-tetrafluoroethane have been derived from studies conducted with laboratory animals. 1,1,1,2-Tetrafluoroethane exhibits relatively low toxicity. A reduction in maternal body weight gain in rabbits exposed to 40 000 ppm (166 800 mg/m³) 1,1,1,2-tetrafluoroethane and signs of delayed fetal development in rats following exposure of the dams to 50 000 ppm (208 500 mg/m³) 1,1,1,2-tetrafluoroethane have been noted in developmental toxicity studies. In other toxicological investigations, adverse health effects have not been observed following exposure to concentrations up to 10 000 ppm (41 700 mg/m³). The weight of evidence for carcinogenicity is limited to an increased incidence of Leydig cell adenomas following exposure to 50 000 ppm (208 500 mg/m³), and 1,1,1,2-tetrafluoroethane has not been found to be genotoxic in studies conducted to date.

The low toxicity of 1,1,1,2-tetrafluoroethane to the few aquatic organisms tested as well as its high volatility indicate negligible risk to aquatic organisms.

Atmospheric effects have been assessed by modelling. Recent observations have shown a rapid increase in atmospheric concentrations of 1,1,1,2-tetrafluoroethane, mainly as a result of emissions over the past decade. Modelling indicates insignificant ozone depletion potential, a significant global warming potential, and negligible acidification potential.

Concise International Chemical Assessment Document, No. 11
1998, iv + 18 pages [E, with summaries in F, S]
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