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1000
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Abstract/Summary
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The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated 2,3,3,3‐tetrafluoropropene to derive a maximum concentration at the workplace (MAK value), considering all toxicity endpoints. Available unpublished study reports and publications are described in detail. The critical effect of 2,3,3,3‐tetrafluoropropene was focal myocardial necrosis and inflammation in pregnant rabbits from 2500 ml/m3 (the lowest concentration tested) and above. A NOAEC of 500 ml/m3 was derived from a 28‐day inhalation study in rabbits for these effects. As the rabbit is the most sensitive species and it has not been demonstrated that the findings obtained in the heart are a species‐specific effect, the NOAEC of 500 ml/m3 serves as the basis for the derivation of the MAK value. Although this was only a 28‐day inhalation study, the concentration in the range of the NOAEC probably has a greater influence than the exposure duration. Only a slight decrease in the NOAEC is expected after long‐term exposure, therefore, the concentration is not converted from 7‐day exposure per week to 5‐day exposure at the workplace. As no effects on the heart were observed in rats up to 50 000 ml/m3 and in minipigs up to 10 000 ml/m3, rabbits are assumed to have a markedly higher sensitivity as regards effects on the heart, although the mechanism is not exactly known. Therefore, a MAK value of 200 ml/m3 has been established. 2,3,3,3‐Tetrafluoropropene was found to be mutagenic in the Salmonella strain TA100 and Escherichia coli. Chromosomal aberration tests in vitro and micronucleus tests in vivo yielded negative results. There are insufficient data to be able to classify 2,3,3,3‐tetrafluoropropene in one of the carcinogen categories. The NOAEC for developmental toxicity was 4000 ml/m3 and 20 times higher than the MAK value of 200 ml/m3. Thus, damage to the embryo or fetus is unlikely when the MAK value is observed and 2,3,3,3‐tetrafluoropropene is classified in Pregnancy Risk Group C. There are no data available for sensitization. Skin contact is not expected to contribute significantly to systemic toxicity.
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