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EC number: 213-603-0
CAS number: 993-07-7
No irritation data are available for the registered
substance. Data are available for the structural analogue,
triethylsilane (CAS 617-86-7), from skin and eye irritation studies
conducted in accordance with OECD 404 and 405 respectively and in
compliance with GLP. Triethylsilane was not irritant in rabbits.
There are no data available to
assess the skin and eye irritation potential of trimethylsilane, and
testing is not technically feasible because the substance is a gas.
Therefore data for the structural analogue substance triethylsilane (CAS
617-86-7) have been used to assess its skin and eye irritation
potential. Triethylsilane was found to be not irritating to rabbit skin
Information on triethylsilane is
included for completeness only.
To reduce animal testing REACH
recommends to make use of a read-across approach where appropriate based
on the high accordance in properties relevant for the specific endpoint.
In the case of irritation the relevant properties are structural
similarity as well as physical-chemical properties in the same range. In
the following paragraphs the proposed read-across from triethylsilane to
trimethylsilane is discussed. A report considering read across for all
endpoints is attached in Section 13.
hypothesis is that source and target substances have similar
toxicological properties because they are structurally similar and have
similar physicochemical properties. Trimethylsilane has a half-life in
water of days and triethylsilane is hydrolytically stable, so reaction
products do not need to be considered for the human health hazard
assessment of these substances.
(a) Structural similarity
The registration and read-across
substances are structurally similar and are members of an analogue group
of alkylsilanes. The substances contain a silicon atom to which is
attached three alkyl (methyl/ethyl) groups. For the registered substance
the alkyl groups are methyl, for the read-across substance they are
ethyl. It is not considered likely that decreasing the carbon chain
length by one carbon would be likely to confer additional irritation
properties on the registration substance; however, this cannot be
demonstrated experimentally due to the physical state of trimethylsilane
at ambient temperature and pressure.
(b) Similar physicochemical
The key physicochemical parameters
are summarised below.
Table: Key physicochemical
Molecular weight (gmol-1)
log Kow (parent)
Water solubility (parent)
1400 mg/l (QSAR), limited by condensation reactions following abiotic reaction to silanol
Vapour pressure (parent)
not applicable (substance is a gas)
Based on available information for
the read-across substance triethylsilane, the registered substance,
trimethylsilane, does not require classification for skin and eye
irritation according to Regulation (EC) No 1272/2008.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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