Registration Dossier

Administrative data

Key value for chemical safety assessment

Additional information

2-methylpropane-2-thiol was not mutagenic in two in- vitro bacterial reverse mutation assay (OECD TG 471) (CP Chem, 1982a and Verspeek-Rip, 2015) and an in vitro mammalian cell gene mutation (mouse lymphoma) assay (OECD TG 476) (CP Chem, 1982b), both with or without metabolic activation. In an in vitro sister chromatid exchange assay (OECD 476) (CP Chem, 1982c), 2-methylpropane-2-thiol induced, in the presence of metabolic activation, a statistically significant increase in the number of SCEs per cell and SCEs per chromosome; but no significant increase was seen in the remaining dose levels, and no dose level showed a two-fold increase in SCEs. The increases in SCEs ranged from 0.9 to 1.2-fold in the absence of metabolic activation and 1.0 to 1.5-fold in the presence of activation. Therefore, 2-methylpropane-2-thiol was not considered to be positive in this test system. In an in vivo mouse micronucleus assay (OECD 474) (Putman et al., 1995), 2-methylpropane-2-thiol exposure resulted in slight reductions in the ratio of polychromatic erythrocytes to total erythrocytes but did not induce chromosomal mutations. 


Short description of key information:
2-methylpropane-2-thiol was not mutagenic in two in vitro bacterial reverse mutation assay (OECD TG 471) and in the in vitro Mammalian Cell Gene Mutation (mouse lymphoma) assay (OECD TG 476), with or without metabolic activation. In an in vitro sister chromatid exchange assay (OECD TG 473), 2-methylpropane-2-thiol did not induce a statistically significant genotoxic effect. In an in vivo mouse micronucleus assay (OECD TG 474), 2-methylpropane-2-thiol did not induce chromosomal mutations.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

According to REGULATION (EC) No 1272-2008 and the available in vitro and in vivo genotoxicity data:

- Germ cell mutagenicity: not classified

2 -methylpropane-2-thiol is not genotoxic.