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Administrative data

Description of key information

In a 90-day inhalation study (DCC, 1993) in rats, conducted in accordance with OECD 413, the NOAEC was determined to be 100 ppm (813 mg/m3).
3-Chloropropyltrimethoxysilane was tested in an inhalation OECD 422 study (Marburger et al., 2005), whole-body in rats, up to and including the highest concentration of 100 ppm. In this study there were no signs of general toxicity. Therefore based on these results the NOAEC was established to be at least 100 ppm (813 mg/m3).
There are no data for the oral and dermal routes.

Key value for chemical safety assessment

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion
Dose descriptor:
NOAEC
813 mg/m³

Additional information

There are several reliability score 1 studies for repeated inhalation of 3-chloropropyltrimethoxysilane. The 90-day study was selected as the key study as it tested over the longest duration.

In the key study, microscopic examinations did not reveal any adverse findings in females exposed to 0.5 or 5 ppm. Eight of 10 male animals in the 0.5 ppm exposure group were reported as normal. The two remaining male animals exhibited minimal chronic cystitis of the urinary bladder. Nine of 10 male animals were reported as normal in the 5.0 ppm exposure group. The remaining male animals exhibited minimal chronic cystitis of the urinary bladder. Treatment-related histopathological effects were observed in the 100 ppm group animals. Increased incidence of hyperplasia of the urinary bladder epithelium was noted in both sexes of this group.

It is not known whether the urinary bladder was inflated by a fixative before microscopic examination. Without inflation of the urinary bladder the relevance of the hyperplasia is questionable. Based on the fact that the hyperplasia of the bladder was mild /minimal and in some cases associated with a minimal inflammation (cystitis) it can presumed that if the stimulus for the hyperplastic changes is removed the hyperplasia will resolve within a matter of weeks and the urinary bladder will return to a normal histological appearance.A minimal/mild change of the urinary bladder not associated with any clinical symptoms or changes in urine parameters does not reflect a marked organ dysfunction. Therefore, the mild/minimal hyperplastic effects are not considered as adverse and the NOAEC is 100 ppm (813 mg/m3).

In a supporting study, 3-chloropropyltrimethoxysilane was tested in an inhalation OECD 422 study (Marburgeret al., 2005), whole-body in rats, up to and including the highest concentration of 100 ppm. In this study there were no signs of general toxicity. Therefore based on these results the NOAEC was established to be at least 100 ppm (813 mg/m3).

Justification for classification or non-classification

Based on the fact that the urinary bladder effects were minimal and are expected to be reversible, there is no proposal to classify trimethoxy(3-chloropropyl)silane for adverse effects following repeated exposures.