JACC Report 42 – Tetrafluoroethylene

Abstract

JACC 042 : Tetrafluoroethylene (CAS No. 116-14-3) | December 2003

This report has been produced as part of the ECETOC Joint Assessment of Commodity Chemicals (JACC) programme. It presents a critical evaluation of the toxicity and ecotoxicity data on tetrafluoroethylene (TFE) that could inform the hazard/risk assessment required under current OECD/EU schemes a,b. In the USA, TFE is included in the EPA Chemical Right-to-Know Initiative c. TFE is a colourless gas that is mainly used in the production of polytetrafluoroethylene and other fluorinated polymers. It is sparingly soluble in water. Any TFE released into the environment will be distributed to the atmosphere, where it will quickly degrade to carbon dioxide and hydrogen fluoride that is washed out by rain. TFE does not contribute directly to the greenhouse effect (global warming) and has no effect on the stratospheric ozone layer, but may enhance the formation of tropospheric ozone, more or less significantly, depending on the quantities emitted. In the aquatic environment, no hydrolysis of TFE will occur and it is not prone to rapid biodegradation and bioaccumulation. TFE will not adsorb significantly to soils and sediments. Although experimental data are not available, model calculations predict that that TFE is not toxic to environmental organisms. Short-term inhalation exposure of laboratory animals to high doses of TFE did not evoke cardiac sensitisation or anaesthetic effects that are typically found with other fluorinated compounds. With TFE, the primary effect was damage to the kidney, though overall the toxcity was judged to be low. Longer-term exposures also resulted in a low level of toxicity manifest as kidney effects and anaemia in rats and mice, and possibly testicular changes in hamsters. No specific study of the reproductive effects of TFE is available. TFE is not genotoxic either in vitro or in vivo. The principal metabolic product (cysteine conjugate) of TFE, S 1,1,2,2-tetrafluoroethyl-L-cysteine, is also not mutagenic in vitro. In long-term carcinogenicity studies in rats and mice, repeated inhalation of high doses of TFE produced tumours of the kidney in rats and mice and in the liver of mice. These tumours were considered to have been caused by metabolites of TFE and in vitro studies of the comparative metabolism in different species suggest that following exposure to TFE the risk to humans of developing tumours of the kidney would be much lower than in rats or mice. In mice, however, there were also more tumours of the haematopoietic system in some organs. The current lack of knowledge about the mechanisms involved in the development of these three tumours types precludes a full evaluation of the hazard to humans from exposure to TFE.