Registration Dossier

Administrative data

Description of key information

In accordance with Column 2 of REACH Annex VII, the in vivo skin sensitisation study (required in Section 8.3.2) do not need to be conducted as the substance is classified as corrosive to the skin.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:

The registration substance was tested in a dose range finding study for skin sensitisation (see Section 7.4). The main study was terminated due to adverse effects observed in the test animals, but it was conducted according to an appropriate OECD test guideline, and in compliance with GLP (Eurofins, 2016).

Following a 6 -hour occluded topical application of 25, 50, 75 and 100 % test substance in dry acetone to the flanks of 2 guinea pigs, signs of systemic toxicity and severe skin irritation (necrosis) were observed in all of the animals. One animal, treated with 2.5 and 5.0 % of test substance, showed grade 2 erythema, which was evident after 72 hours. One animal, treated with 0.5 and 1.0 % test substance, showed grade 1 erythema which was fully reversible within 72 hours.

In combination with the results of historical skin irritation studies, the findings of the sensitisation sighting study were taken as evidence that the registration substance should be classified as corrosive to skin. As such, it is considered that further testing for skin irritation/corrosion is not appropriate despite the fact that the available studies do not meet current guideline standards. There is sufficient evidence to classify the substance as Corrosive Category 1C.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Based on the available data for 2,2,4,4,6,6-hexamethylcyclotrisilazane no tests for skin sensitisation are required, because the substance is classified as corrosive.