Registration Dossier

Administrative data

Key value for chemical safety assessment

Additional information

Information is available from a reliable study on bacterial mutagenicity. Mammalian cytogenicity and mutagenicity studies are available for the related substance, trichlor(methyl)silane, which is considered a close structural analogue of the registered substance. Trichloro(methyl)silane and trichloro(ethyl)silane are both small molecule alkylchlorosilanes containing Alkyl-Si and Cl-Si groups.

The key in vitro cytogenicity study showed slight evidence of effects, but in the opinion of the reviewer these were not biologically significant as the increase in aberrations was very slight and not dose related. The results of mutagenicity assays were negative. Data from an in vivo Mammalian bone marrow chromosome aberration test for trichloro(methyl)silane (ip study) in rat support the negative conclusion, but the study did not demonstrate toxicity to the target organ, so it is not included in the key studies.


Short description of key information:
In vitro:
Gene mutation (Bacterial reverse mutation assay / Ames test): negative with and without activation in all strains tested (OECD TG 471)
Cytogenicity in mammalian cells: read across from analogous substance: negative in cultured human lymphocytes without activation (similar to OECD TG 473)
Mutagenicity in mammalian cells: read across from analogous substance: negative in L5178Y mouse lymphoma cells (similar to OECD TG 476)

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

The available information for the substance indicates that when tested in vitro, trichloro(methyl)silane (CAS number 75 -79 -6) did not induce mutations in bacterial cells. The analogous substance, trichloro(ethyl)silane, did not indicate a biologically significant clastogenicity (induction of chromosome aberrations) in an in vitro cytogenicity study, nor an increase of revertants in a mammalian mutagenicity study. It is concluded that classification for mutagenicity is not required.