Registration Dossier

Administrative data

Key value for chemical safety assessment

Additional information

The available studies are of sufficient reliability to be selected as a key study. There were no duplicate studies. For genetic toxicity endpoints were there were no data available for the registered substance, the key studies for the related substance, Dichloro(dimethyl)silane (CAS number 75 -78 -5) were selected as key studies. The results of all the studies were in agreement. It is considered appropriate to read across the genetic toxicity results for dichloro(dimethyl)silane as it is considered a close structural analogue of chloro(dimethyl)silane: both are small molecule alkylchlorosilanes containing Me-Si and Cl-Si groups. In addition, bacterial mutagenicity results for the two substances are in agreement, and neither substance contains a structural alert for genetic toxicity.


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 CAS 75-78-2: negative in L5178Y mouse lymphoma cells (similar to OECD TG 473)
Mutagenicity in mammalian cells: read-across from analogous substance CAS 75-78-2: negative in L5178Y mouse lymphoma cells (similar to OECD TG 476)

In vivo:
Chromosome aberration assay in rat (ip administration): read-across from analogous substance CAS 75-78-2: negative in bone marrow cells (similar to OECD 475)

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

The available information indicates that chlorodimethylsilane (CAS number 1066 -35 -9) does not cause mutagenicity in bacteria. Negative results for the analogous substance, dichloro(dimethyl)silane (CAS number 75 -78 -5) for in vitro mammalian mutagenicity and cytogenicity and an in vivo chromosome aberration assay can be read across to the registration substance. Therefore it is considered that classification for mutagenicity is not required.