Registration Dossier

Administrative data

Key value for chemical safety assessment

Additional information

In vitro studies are available for bacterial mutagenicity and cytogenicity in mammalian cells. The most reliable study available for each endpoint was chosen. Where there was more than one reliable study, the most recent studiy was selected. Where reliable studies were not available for the test substances, studies for an analogous substance were selected. The results in bacterial cells are in agreement, both giving negative results. There was evidence for clastogenicity (causing chromosomal aberrations) in the presence of metabolic activation in vitro. An in vivo study did not support this finding, so it is concluded that the in vitro result does not reflect an ability to cause chromosome aberrations in vivo. In view of the availability of an in vivo study, it is not considered necessary to test for mutagenicity in mammalian cells in vitro.


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: Negative without activation, positive structural, negative numerical with activation (OECD TG 473)
In vivo:
Micronucleus assay inhalation study in rat: Negative (similar to OECD TG 474)

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

The available information for the substance indicates that trimethoxysilane (CAS number 2487 -90 -3) does not induce mutations in bacterial cells. The substance does cause chromosomal aberrations in vitro in the presence of metabolic activation, but this was not confirmed in an in vivo study, so it is concluded that trimethoxysilane is not genotoxic.