On October 21, 2026, the Government of Canada officially published the Order Amending the Domestic Substances List (SOR/2026-208) in the Canada Gazette, adding the commonly used rubber industry substance TMTD (tetramethylthiuram disulfide, CAS 137-26-8) to the Significant New Activity (SNAc) provisions of the Domestic Substances List (DSL).
Background
In Canada, TMTD is primarily used as a processing regulator in solid rubber production, as well as in automotive parts, sealants/adhesives, and small amounts of food packaging materials. Environmental releases mainly come from wastewater associated with solid rubber production. While it degrades rapidly in the environment, it is highly toxic to aquatic organisms. In 2021, TMTD was assessed and found to meet the environmental harm criteria under paragraph 64(a) of the Canadian Environmental Protection Act (CEPA).
Amendment Details
TMTD has been removed from Part 1 of the DSL and added to Part 2, Division 1, subject to SNAc controls. The following two scenarios will trigger these controls:
- Manufacturing more than 100 kg of TMTD in any calendar year; or
- Using a total of more than 100 kg per year in the manufacture of liquid rubber or latex products.
Note: Substances that meet the definition of "research and development substances" under the New Substances Notification Regulations are exempt.
This amendment will come into force 180 days after registration (April 2027). Those intending to engage in a significant new activity must submit the required information at least 180 days before the activity begins, and Environment and Climate Change Canada will complete its assessment within 180 days of receiving the information.
