Registration Dossier

Administrative data

Description of key information

In an acute toxic class study conducted to OECD 423 and to GLP (LPT, 2002a) the acute oral LD50 of (3-chloropropyl)dimethoxymethylsilane was in the range 200-2000 mg/kg bw in rats. All animals of both sexes showed slight to moderately reduced motility, slight to moderate ataxia, slight to moderately reduced muscle tone and slight to moderate dyspnoea from 15 minutes up to 24 hours after administration at 2000 mg/kg bw. 
There are no acute dermal toxicity data for (3-chloropropyl)dimethoxymethylsilane. Therefore data have been read across from the structurally related (3-chloropropyl)diethoxymethylsilane.
In an acute dermal limit study (Hüls AG, 1997b) conducted to OECD 402 and GLP, the dermal acute LD50 for the related substance, (3-chloropropyl)diethoxymethylsilane, was greater than 2000 mg/kg bw in Wistar rats. There were no significant clinical effects.
There are no inhalation studies.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LD50
Value:
200 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
2 000 mg/kg bw

Additional information

The acute oral toxicity study is the only study of this kind for this test substance. The read across data for acute dermal toxicity are supported by the results of the skin irritation study on (3-chloropropyl)dimethoxymethylsilane itself in which no systemic effects were observed.

The read-across substance and the registered substance share a common 3-chloropropyl sidechain, and are members of a small analogue group containing this functional group and other chloroalkyl groups. The two substances share a common hydrolysis product, (3-chloro

propyl)methylsilanediol. Dermal uptake of the read-across substance is likely to be slightly greater due to its anticipated slower hydrolysis rate and higher log Kow, so this is a worst-case approach. There is no indication of acute toxicity by the dermal route in studies available for substances in this analogue group and data for the oral route are comparable. Further information is given in Section 5.6.3 and in a supporting report attached in Section 13 of the IUCLID dossier (PFA, 2013s).

Justification for selection of acute toxicity – oral endpoint
The selected study is the only acute oral toxicity study that is available for the registered substance. It was conducted in accordance with an appropriate OECD test guideline and in compliance with GLP.

Justification for selection of acute toxicity – dermal endpoint
The selected study was the only acute dermal toxicity study available for the most relevant surrogate substance. It was conducted in accordance with an appropriate OECD test guideline and in compliance with GLP.

Justification for classification or non-classification

Based on the available acute toxicity data, (3-chloropropyl)dimethoxymethylsilane is classified 'Acute Toxic 4 (oral)' with the hazard statements 'H302: Harmful if swallowed and according to Regulation (EC) No 1272/2008.