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Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

Tert-butyl peroxypivalate was tested in a Maximisation Test in albino guinea pig according to EU method B.6 and OECD guideline no. 406.

The test item concentrations selected for the main study were based on the results of a preliminary study.

In the main study, experimental animals were intradermally injected with a 10 % concentration (1. induction). The test animals were epidermally exposed to the undiluted test substance seven days after the first induction

Control animals were similarly treated, but with the vehicle (Corn oil) only. Two weeks after the epidermal application all animals were challenged with a 20 % test item concentration and the vehicle.

Skin reactions varying between grades 1 and 2 were observed in eight experimental animals in response to the 20 % test item concentration, 24 and/or 48 hours after exposure.

A skin reaction of grade 1 was observed in one control animal in response to the 20 % test item, 48 hours after exposure.

One experimental animal was found dead on day 8. Macroscopic post-mortem examination of the animal showed dark red discolouration of the lungs and haemorrhages in the lungs and a reduction in size of the thymus. It was considered that the death of this animal was incidental and that the study outcome, based on healthy surviving animals, was not adversely affected.

No further mortality occurred and no further symptoms of systemic toxicity were observed in any of the animals of the main study.

Taking into account the occurrence and intensity of the responses and comparing these with the skin reactions seen in the control animals, it was considered that hypersensitivity to tert-butyl peroxypivalate had been induced in eight (of nine) experimental animals. The response seen in the control animal was considered to be a non specific skin reaction. These results indicate a sensitisation rate of 89 per cent. Thus, the test item TBPPI is considered to be skin sensitising.

Migrated from Short description of key information:
Based on the results obtained from testing the substance was considered as skin sensitiser.

Justification for selection of skin sensitisation endpoint:
Only one study available.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Based on available data on sensitisation properties, tert-butyl peroxypivalate was classified and labelled as Cat. 1B (H317: May cause an allergic skin reaction) according to Regulation (EC) No 1272/2008 (CLP).