Benzotriazoles and Benzothiazoles Group
Information sheet
These substances were identified for action under the Chemicals Management Plan (CMP). The assessment focused on 15 substances referred to collectively under the CMP 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 its precursors and is not limited to the six benzothiazole substances in the table below.
| Substance group | Subgroup | CAS RN | Common name or acronym | DSL name | Public comments on the draft screening assessment | Final assessment | Proposed risk management approach | Conclusion on section 64 criteria | Follow-up activities |
|---|---|---|---|---|---|---|---|---|---|
| Benzotriazoles and Benzothiazoles Group | Benzotriazoles | 95-14-7 | Benzotriazole | 1H-Benzotriazole | HTML | 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)- | |||||||
| 3846-71-7 | 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 a | 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 | Not available | 1H-Benzotriazole-1-methanamine, N,N-bis(2-ethylhexyl)-5-methyl- | |||||||
| 94270-86-7Footnote a | Not available | 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 | Refer to the proposed risk management approach | |||
| 95-33-0 | CBS | 2-Benzothiazolesulfenamide, N-cyclohexyl- | |||||||
| 120-78-5 | 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- | |||||||
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| Date | Activity |
|---|---|
| August 29, 2026 | Publication in Canada Gazette, Part I, of a notice under section 71 of Canadian Environmental Protection Act, 1999 (CEPA). |
| March 8, 2025 | Publication of the final assessment. The Risk Management Approach for 2-Mercaptobenzothiazole (MBT) and its Precursors (from the Benzotriazoles and Benzothiazoles Group) was also published for a 60-day public comment period. The related notice was published in the Canada Gazette, Part I, Vol. 159, No. 10. |
| June 24, 2023 | Publication in Canada Gazette, Part I, of a notice under section 71 of the CEPA. |
| 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. |
Additional considerations
Although TBBS, CBS, MBTS, MBT, SMBT and DCBS are not considered to be harmful to human health at current levels of exposure, these substances are associated with effects of concern. Therefore, there may be a concern to human health if exposures were to increase. For this reason, these substances may be considered in future initiatives to track their commercial status or identify new uses or exposures. Monitoring of MBT in surface water and sediment which is planned as part of the ecological component of the performance measurement evaluation will also help track human exposures. Prior to monitoring, analytical methods will need to be developed.
Information gathering
Section 71 CMP 2026 – Phase 1
In August 2026, a notice was published in the Canada Gazette, Part I: Vol. 160, No. 35 – August 29, 2026, under section 71 of CEPA. This notice applies to six substances included in this substance grouping (CAS RNs 120-78-5, 149-30-4, 2492-26-4, 4979-32-2, 95-31-8, and 95-33-0). More information is available on the information gathering with respect to certain substances under the CMP web page.
Section 71 CMP 2023
In June 2023, a notice was published in the Canada Gazette, Part I: Vol. 157, No. 25 – June 24, 2023 under section 71 of CEPA. This notice applies to 11 benzothiazole substances. More information is available on the information gathering with respect to certain substances under the CMP web page.
Background
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.