Benzotriazoles and Benzothiazoles Group

These substances were identified for action under the Chemicals Management Plan (CMP). This screening assessment focuses on 15 of 17 substances referred to collectively as the Benzotriazoles and Benzothiazoles Group. The substances in the benzothiazoles subgroup all contain the 2-mercaptobenzothiazole (MBT) moiety; therefore, the conclusion for this subgroup includes MBT and substances that are precursors to MBT, and is not limited to the 6 substances in the table below.

Summary of publications
Substance group Subgroup CAS RN Common name or acronym DSL name Draft screening assessment Risk management scope Proposed conclusion on section 64 criteria Follow-up activities
Benzotriazoles and Benzothiazoles Group Benzotriazoles 95-14-7Footnote a Benzotriazole 1H-Benzotriazole HTML none Do not meet None planned at this time.
3147-75-9 UV-329 Phenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)-
3846-71-7Footnote a UV-320 Phenol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1,1-dimethylethyl)-
3896-11-5 UV-326 Phenol, 2-(5-chloro-2H-benzotriazol-2-yl)-6-(1,1-dimethylethyl)-4-methyl-
29385-43-1Footnote b Tolyltriazole 1H-Benzotriazole, 4(or 5)-methyl-
36437-37-3 UV-350 Phenol, 2-(2H-benzotriazol-2-yl)-4-(1,1-dimethylethyl)-6-(1-methylpropyl)-
70321-86-7 UV-234 Phenol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)-
80595-74-0 n/a 1H-Benzotriazole-1-methanamine, N,N-bis(2-ethylhexyl)-5-methyl-
94270-86-7Footnote b n/a 1H-Benzotriazole-1-methanamine, N,N-bis(2-ethylhexyl)-ar-methyl-
Benzothiazoles 95-31-8a TBBS 2-Benzothiazolesulfenamide, N-(1,1-dimethylethyl) HTML Meet one or more of the criteria Under consideration.
For MBT and its precursors, refer to risk management scope.
95-33-0Footnote a CBS 2-Benzothiazolesulfenamide, N-cyclohexyl-
120-78-5Footnote c MBTS Benzothiazole, 2,2'-dithiobis-
149-30-4 MBT 2(3H)-Benzothiazolethione
2492-26-4 SMBT 2(3H)-Benzothiazolethione, sodium salt
  4979-32-2 DCBS 2-Benzothiazolesulfenamide, N,N-dicyclohexyl-
Date Activity
March 2022 Anticipated publication of the Final Screening Assessment for the Benzotriazoles and Benzothiazoles Group and the proposed Risk Management Approach for 2-Mercaptobenzothiazole (MBT) and its Precursors.
March 6, 2021 Publication and start of 60-day public comment period on the Draft Screening Assessment for the Benzotriazoles and Benzothiazoles Group (including follow-up activities for TBBS, CBS, MBTS, MBT, SMBT, and DCBS) and the Risk Management Scope for 2-Mercaptobenzothiazole (MBT) and its Precursors. The related notice was published in the Canada Gazette, Part I: Vol. 155, No. 10.


Two other substances were identified as being part of the Benzotriazoles and Benzothiazoles Group at the outset of the third phase of the CMP. These substances (CAS RNs 80584-90-3 and 21564-17-0) were subsequently determined to be of low concern to both human health and the environment through other approaches. The conclusion for CAS RN 80584-90-3 is provided in the Final Screening Assessment for Substances Identified as Being of Low Concern using the Ecological Risk Classification of Organic Substances and the Threshold of Toxicological Concern (TTC)-based Approach for Certain Substances. The conclusion for CAS RN 21564-17-0 is provided in the Final Screening Assessment for the Rapid Screening of Substances with Limited General Population Exposure.

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