JACC Report 50 – 1,1,1,2-Tetrafluoroethane (HFC-134a) Second edition

Abstract

JACC 050 : 1,1,1,2-Tetrafluoroethane (HFC-134a) (CAS No. 811-97-2) (Second Edition) | January 2006

This report has been produced as part of the ECETOC Joint Assessment of Commodity Chemicals (JACC) programme.
It updates an earlier ECETOC review and presents a critical evaluation of the available data on the ecotoxicity, toxicity, environmental fate and impact of 1,1,1,2-tetrafluoroethane (HFC-134a), including results of recent and unpublished studies conducted by the Programme for Alternative Fluorocarbon Toxicity Testing (PAFT).
1,1,1,2-Tetrafluoroethane (HFC-134a) is a colourless, non-flammable gas that is mainly used, alone or blended with other components, to replace hydrochlorofluorocarbons in refrigeration and air conditioning at home, in cars and in industry. Although HFC-134a has a high global warming potential, its contribution to the greenhouse effect is, currently, insignificant due to its low atmospheric concentration. HFC-134a does not cause ozone depletion because it does not contain chlorine or bromine. Any HFC-134a released to the environment will rapidly volatilise to the atmosphere, where it is slowly degraded to trifluoroacetic acid, formic acid, hydrofluoric acid and carbon dioxide. Trifluoroacetic acid is relatively stable in the environment.
The toxicity of HFC-134a to experimental animals is extremely low. After a single brief exposure to the gas, narcosis may occur at very high concentrations (500,000 ppm; 2,080,000 mg/m3). HFC 134a also causes slight skin or eye irritation, but it is not a skin sensitiser. Exposure to high levels of HFC-134a (80,000 ppm; 334,000 mg/m3) can induce cardiac sensitisation to adrenaline. HFC-134a has no adverse effects on fertility or foetal development and shows no non-neoplastic target organ toxicity in long-term inhalation studies in rats exposed to up to 50,000 ppm (208,000 mg/m3) for 1 year.
HFC-134a is not genotoxic in vitro or in vivo. No tumours due to HFC-134a were seen in rats dosed with HFC-134a by gavage (dissolved in corn oil) for 1 year, or in female rats following daily inhalation for 2 years. In the latter study, male rats inhaling 50,000 ppm showed increases in the incidence of testicular Leydig cell hyperplasia and benign Leydig cell adenoma. These tumours were most likely to have been induced by a non-genotoxic mechanism and are of no significance for humans. Therefore, it is considered that HFC 134a does not present a carcinogenic risk to humans at any foreseeable levels of exposure.
HFC-134a has been used as a propellant in metered dose inhalers for several years. There are no known effects resulting from this type of exposure to HFC-134a in humans.
HFC-134a has a low toxicity to aquatic organisms such as trout and water fleas (Daphnia). Although practically non-biodegradable, HFC-134a is unlikely to have any impact on the aquatic environment because of its high volatility and low potential for bioaccumulation.