2-Methyl-2-propanethiol
MAK Value Documentation – Translation of the German version from 2021
Andrea Hartwig1 (Chair of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft)MAK Commission2
1 Institute of Applied Biosciences, Department of Food Chemistry and Toxicology, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, Building 50.41, 76131 Karlsruhe, Germany
2 Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft, Kennedyallee 40, 53175 Bonn, Germany
Abstract
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated data for 2-methyl-2-propanethiol [75-66-1] considering all toxicological end points. Data from a 90-day inhalation study with rats show that the critical effect of 2-methyl-2-propanethiol is its haematotoxic potential. On the basis of the NOAEC of 9 ml/m3 and taking into account the increased respiratory volume at the workplace, the maximum concentration at the workplace (MAK value) has been set at 1 ml/m3. As the critical effect is systemic, Peak Limitation Category II has been assigned with an excursion factor of 2. The NOAEC for developmental toxicity was 11 ml/m3 in mice and 195 ml/m3 in rats. When the increased respiratory volume at the workplace is taken into consideration, a sufficient margin remains between the values determined for rats and the MAK value. In mice, the LOAEC for developmental toxicity was 99 ml/m3 and the NAEC is assumed to be above 11 ml/m3; thus, there is a sufficient margin between these values and the MAK value. Accordingly, damage to the embryo or foetus is unlikely when the MAK value is not exceeded and 2-methyl-2-propanethiol has been classified in Pregnancy Risk Group C. According to skin absorption models, percutaneous absorption is expected to contribute significantly to systemic toxicity. Therefore, 2-methyl-2-propanethiol has been designated with an “H”. 2-Methyl-2-propanethiol can cause sensitization of the skin in animals and has therefore been designated with “Sh”. 2-Methyl-2-propanethiol is not mutagenic in vitro or clastogenic in vivo and no studies in germ cells are available. No carcinogenicity studies have been performed.
