Registration Dossier
Registration Dossier
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EC number: 219-660-8 | CAS number: 2492-26-4
Endpoint summary
Administrative data
Description of key information
Key value for chemical safety assessment
Skin sensitisation
Endpoint conclusion
- Endpoint conclusion:
- adverse effect observed (sensitising)
- Additional information:
SMBT is corrosive, as discussed above. According to REACH regulation Annex VII, chapter 8.3. skin sensitization, column 2, in vivo testing does not need to be conducted.
However, SMBT is the sodium salt of MBT, which is classified as sensitizing to skin. To consider the skin sensitizing potential of SMBT component MBT, a read across approach with in vivo study data from MBT was conducted.
The skin sensitizing potential of MBT is known from several animal studies. In addition, 2-mercaptobenzothiazole is one of the preferred and recommended positive control substances recommended in OECD Guideline 406 and 429.
The below mentioned study is an example for the skin sensitizing potential of MBT.
The skin sensitizing potential of MBT was evaluated in a GLP and OECD guideline study (TG 406, Guinea-pig maximization test) with female guinea pigs (Bayer AG 1999). The test substance was formulated in physiological saline solution to yield a suspension up to 40 %. Ten animals were administered with the test substance suspensions. A control group of five animals were treated with physiological saline solution. In the treatment group the intradermal induction was done with 5 % and the topical induction with 25 % test substance solution. The challenge was done with 12 % test substance solution and led to skin effects in 7 of 10 animals in the treatment group and to one animal in the control group after 48 hours. Six of 10 animals showed skin effects in the treatment group after 72 hours. In the control group none of the animals showed skin effects after 72 hours. The total number of animals with skin reactions was 70 % in the test substance group and 20 % in the control group.
Migrated from Short description of key information:
SMBT is corrosive, as discussed above. According to REACH regulation Annex VII, chapter 8.3. skin sensitization, column 2, in vivo testing does not need to be conducted.
However, as discussed above (endpoint summary toxicokinetics) SMBT is the sodium salt of MBT. MBT is classified as sensitizing to skin (R43/ category 1). To consider the skin sensitizing potential of SMBT component MBT, a read across approach with in vivo study data from MBT was conducted.
The skin sensitizing potential of MBT was revealed by findings from several guinea pig tests, e. g. guinea pig maximisation test (Bayer AG 1999).
Justification for classification or non-classification
Based on read across data with MBT, SMBT is classified as skin sensitizer according to the classification criteria 67/548/EWG and regulation no. 1272/2008 (GHS).
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