Triacetoxyethylsilane

Endpoint summary

Description of key information

In the key skin irritation/corrosion study (Hazleton, 1989), which was comparable to OECD 405 and conducted to GLP, triacetoxyethylsilane was corrosive to the skin of rabbits following a three minute exposure under semi-occlusive conditions.  In this study grade 2 erythema and edema were observed in all animals within the first hour after dressing removal. The overall reactions peaked between 24 and 48 hours after dressing removal. By 72 hours the edema began to reverse in all of the animals. However, erythema persisted for longer, such that two of the animals still had Grade 4 erythema on Day 14. Burns of varying sizes where observed in five of the six exposed animals. 
There are no in vivo eye irritation studies. 

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

There are two reliable skin irritation/corrosion studies available for triacetoxyethylsilane. Both of these studies clearly showed that this substance is corrosive to the skin. In the supporting study only two of three animals survived the observation period, making a decision about classification more difficult to justify. The key study was selected as all of the rabbits survived until the end of the observation period. In this study the animals were exposed to the test substance for three minutes, rather than the four hours recommended by OECD TG 404. However, in light of the severity of the local reaction to this substance, an exposure period of three minutes is sufficient to clearly distinguish the category for classification.

Therefore triacetoxyethylsilane is corrosive to the skin, is predicted to be severely irritating to the eye and is likely to be a respiratory irritant based on production of acetic acid following hydrolysis.

An in vitro eye irritation study is disregarded as an unsuitable test method was used. Additional testing for eye irritation is not required as the substance is confirmed as corrosive to skin.

In vivo skin and eye irritation data are also available for a preparation containing a mixture of approximately 5% (total) triacetoxyethylsilane and the related substance triacetoxymethylsilane (Bayer AG, 1986). This preparation is similar to products marketed for professional and consumer sealant applications. Minor, reversible effects were observed but the preparation was not irritant to skin or eyes according to EU criteria.

Effects on skin irritation/corrosion: corrosive

Effects on eye irritation: highly irritating

Effects on respiratory irritation: irritating

Justification for classification or non-classification

On the basis of the available in vivo skin irritation/corrision studies, triacetoxyethylsilane is classified 'Skin Corr. 1B' with the hazard statment 'H314: Causes severe skin burns and eye damage' according to the criteria of Regulation 1272/2008/EC. It is assumed that substances that are corrosive to the skin are also damaging to the eyes, so there is no separate labelling for the eyes. There are no specific data for respiratory irritation.