Triethylsilane

Endpoint summary

Description of key information

In an acute oral toxicity with triethylsilane in the rat (Crl: CD), the LD₅₀ was >2000 mg/kg bw (OECD Guideline 401, GLP compliant, LPT 2002a).

In an inhalation toxicity whole-body vapour inhalation acute study with the surrogate substance, trimethylsilane, in the Fischer 344 rat, the LC₅₀ after a 4 hour exposure period was greater than 1774 ppm, which is equivalent to > 5.4 mg/l, >5400 mg/m³ (OECD Guideline 403, GLP compliant, Dow Corning Corporation, 2001).

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

5 400 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Data are available for triethylsilane from an acute oral toxicity study. No further data are available for the registered substance, so data have been read across from an inhalation toxicity study on the structural analogue, trimethylsilane (CAS 993-07-7).

In the key acute oral toxicity study, triethylsilane was tested in a study conducted according to OECD 423 and in compliance with GLP (LPT 2002a). The test substance was administered by gavage to one group of 3 male and 3 female rats. Rats were dosed at 2000 mg/kg bw. No clinical signs of systemic toxicity were observed, no deaths occurred, and no abnormalities were found post mortem. The LD₅₀ was determined to be >2000 mg/kg bw.

Trimethylsilane has been tested in accordance with OECD 403 and in compliance with GLP. No treatment-related effects were observed (Dow Corning Corporation, 2001). It is concluded that the whole-body inhalation LC₅₀ value for trimethylsilane in the Fischer 344 rat is greater than 1774 ppm (5.4 mg/L, 5400 mg/m³), the highest concentration tested.

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 acute toxicity the relevant properties are structural similarity, hydrolysis stability and the physical-chemical parameters in the same range.

Read-across hypothesis

The read across hypothesis is that triethylsilane and trimethylsilane are both hydrolytically stable at pH7 on the timescale of an acute inhalation toxicity test, and are structurally similar with similar physicochemical properties and therefore are expected to have similar toxicity profiles.

The acute dermal toxicity study on analogue substance, tetramethylsilane (CAS 75-76-3) is included in support of the read-across justification, as data for this substance are used as key data for skin sensitisation, repeated dose toxicity, genetic toxicity and toxicity to reproduction.

See Section 'Repeated dose toxicity' for further justification of the read-across.

Justification for classification or non-classification

Based on the available acute oral and inhalation toxicity data, triethylsilane does not require classification for acute toxicity according to Regulation (EC) No 1272/2008.