Hydroxytrimethylsilane

Endpoint summary

Description of key information

In a skin irritation study conducted to OECD 404, but not to GLP (Bayer AG, 1986a), New Zealand white female rabbits did not show any signs of skin irritation following a four hour dermal exposure to 0.5 ml undiluted trimethylsilanol. There were no signs of systemic toxicity.

In an eye irritation study conducted to OECD 405, but not to GLP (Bayer AG, 1985b), trimethylsilanol was not irritating to the eyes of rabbits. In an acute Inhalation Toxicity study (WIL, 2007), rats exhibited signs of respiratory tract irritation.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

In a skin irritation study conducted to OECD 404, but not to GLP (Bayer AG, 1986a), three female New Zealand white rabbits were dermally (shaved, intact) exposed to 0.5 ml of undiluted trimethylsilanol for four hours. After four hours the test substance was washed off the skin with water, and skin reactions were recorded for up to 72 hours. None of the animals had any erythema or oedema at any time point, and therefore the test substance was concluded not to be a skin irritant.

In an eye irritation study conducted to OECD 405, but not to GLP (Bayer AG, 1985b), trimethylsilanol was slightly irritating to the eyes of three male rabbits following a 24 hour exposure. All animals had grade 1 corneal opacity at 60 minutes, which increased in severity (to grade 2) in one animal at 24 and 48 hours. All animals had conjuctival redness (grade 1-3) and conjunctival oedema (chemosis: grade 1-2). All opacity and conjuctival effects were reversed by seven days after treatment. There were no effects on the iris. The irritation did not meet the EU criteria for classification.

There was evidence of respiratory tract irritation in an acute inhalation toxicity study (WIL, 2007), in which groups of five male and female Sprague-Dawley rats were exposed to trimethylsilanol for four hours by whole-body vapour inhalation to measured concentrations of 1824, 3517 and 7443 ppm. Clinical signs of respiratory irritation (at 6.7 and 13.0 mg/L) immediately following exposure included decreased and shallow respiration, rales, and/or laboured breathing. Gross necropsy findings in animals that died before study termination included dark red areas/discoloration on the lungs.

Justification for classification or non-classification

Based on the available data trimethylsilanol is not classified for skin and eye irritation under Regulation (EC) No 1272/2008.

Following inhalation exposures there were signs of respiratory tract irritation; however, the classification for acute inhalation toxicity is protective for this effect.