Registration Dossier

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Additional information:

Concerning the skin sensitisation of the TS two in vivo studies were performed.

Both studies comply with the OECD Principles of Good Laboratory Practice (GLP).

Under the experimental conditions employed in the 1988 study, significant differences between the test group and the vehicle-treated controls were seen after intradermal challenge application, i.e. when the skin barrier was intentionally by-passed.

4/20 animals were positive at the 24 hours evaluation after epidermal challenge. However, these reactions after epidermal challenge were only of slight degree and in one animal faded away within 24 hours. Therefore, the slight reactions observed after epidermal challenge are considered not to be allergic.

The negative results upon epidermal challenge demonstrate that, in artificially sensitised guinea-pigs, exposure of the intact skin to the test article does not provoke contact dermatitis.

In the 1991 study moderate allergenic potency was concluded after the second challenge. According to the EEC classification applied the TS is considered to be a sensitizer.


There is no obvious reason explaining the different test results in the two studies. Both studies are in accordance with OECD guideline or similar to OECD guideline in force at time of study conduction. Further on both studies are quality checked and in compliance with the Principles of Good Laboratory Practice. Therefore they should be assessed as reliable without restriction (Klimisch 1, GLP guideline study).The purity of both test items was different and there may be different impurities which lead to a sensitising effect. This can not finally be assessed.

Migrated from Short description of key information:
Concerning the skin senisitisation of the TS two in vivo studies were performed. Both can be assessed as reliable
without restriction. However the results of the studies differ and lead to different classification.
According to the precautionary principle the TS should be classified and labelled.

Justification for classification or non-classification

 According to the precautionary principle the TS should be regarded as a skin sensitizer and preliminary classified and labelled as such.