Registration Dossier

Administrative data

Description of key information

The most reliable study available for skin irritation (Dow Corning Corporation, 1993a) was selected as the key study and found hexamethldisilazane to be mildly irritating to skin. Less reliable supporting studies were conducted under occlusive conditions and resulted in corrosive findings, which were considered to be attributable to increased hydrolysis of hexamethyldisilazine and production of ammonia which is known to be corrosive to skin.
The most reliable study available for eye irritation (Dow Corning Corporation, 1993) was selected as the key study and found hexamethldisilazane to be non-irritating to the eye. Additional less reliable studies supported the findings of the key study.

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:
no study available

Additional information

In the case of skin irritation, the most relaible study was selected as the key study. The most reliable study available for eye irritation was selected as the key study. Additional less reliable eye irritation studies supported the findings of the key study.

In the key skin irritation study (Dow Corning Corporation, 1993a) conducted under semi-occlusive conditions gave a result of mild irritancy. Three other skin irritation/corrosion studies (Dow Corning Corporation, 1993; Bushy Run Research Center, 1981 and 1985), which were all similar or equivalent to OECD 404, gave results of corrosive under occlusive conditions and minimally irritating under semi-occlusive conditions. However, it is considered that hydrolysis of hexamethyldisilazane and therefore production of ammonia, is increased under occlusive conditions compared with semi-occlusive conditions, thus explaining the difference in results.

The key study (Dow Corning Corporation, 1993) for eye irritation, which was conducted to OECD 405, showed hexamethyldisilazine to be a non-irritant in New Zealand White rabbits.


Justification for selection of skin irritation / corrosion endpoint:
The study was conducted according to an appropriate OECD test guideline, and in compliance with GLP.

Justification for selection of eye irritation endpoint:
The study was conducted according to an appropriate OECD test guideline, and in compliance with GLP.

Justification for classification or non-classification

Based on the available data Hexamethyldisilazane does not require classification for skin or eye irritation according to Regulation (EC) 1272/2008.