Canada Gazette, Part I, Volume 156, Number 41: Order Adding a Toxic Substance to Schedule 1 to the Canadian Environmental Protection Act, 1999

October 8, 2022

Statutory authority
Canadian Environmental Protection Act, 1999

Sponsoring departments
Department of the Environment
Department of Health


(This statement is not part of the Order.)


The substance thioperoxydicarbonic diamide ([(H2N)C(S)]2S2), tetramethyl- (CAS RNfootnote 1 137-26-8, hereafter referred to as “TMTD”) meets the ecological criterion for a toxic substance as set out in paragraph 64(a) of the Canadian Environmental Protection Act, 1999 (CEPA or the Act). In accordance with subsection 90(1) of CEPA, the Minister of the Environment and the Minister of Health (the ministers) are recommending that the Governor in Council make an order adding TMTD to Schedule 1 to the Act (the List of Toxic Substances).


The Chemicals Management Plan (CMP) is a federal program that assesses and manages chemical substances and micro-organisms that may be harmful to the environment or human health. The ministers assessed TMTD in accordance with section 74 of CEPA as part of the CMP.

Description, uses, and sources of release

TMTD does not occur naturally in the environment. The substance is primarily used as a process regulator for manufacturing rubber products in Canada. It is used as a component in automotive parts; in sealants and adhesives; and also in registered pest control products. In Canada, it may also be used in the manufacture of certain food packaging materials, as well as in latex rubber cosmetic products.

The Department of the Environment and the Department of Health (the departments) issued mandatory surveys under section 71 of CEPAfootnote 2 encompassing TMTD (reporting year 2008). Information reported by industry indicated that no company manufactured TMTD in Canada above the 100 kilograms reporting threshold; however, between 170 and 403 tonnes of TMTD were imported into Canada in 2008.

Releases of TMTD to the environment via wastewater treatment systemsfootnote 3 are expected, mainly from the loss of raw TMTD powders during weighing and compounding mixer loading operations at industrial solid rubber compounding facilities. The laundering of workers’ clothing and showering of workers at the site are also potential routes of TMTD powder residue entry to wastewater treatment systems. Wastewater generated from equipment and floor cleaning in raw material weighing/handling and compounding areas is considered to be the main source of the release of this substance to the aquatic environment.

In general, TMTD releases to wastewater are expected to be much higher during compounding operations in comparison to processing operations (i.e. curing/vulcanizing). At the solid rubber processing stage, the rubber compounds (sheets) are formed into desired finished shape, combined with other resins or materials (e.g. automotive tire building) and cured (vulcanized). During vulcanization, TMTD releases may occur from substance leaching to autoclave steam and condensate that ultimately enters the wastewater. While releases may occur from processing operations, no information is available to quantify such releases. Finally, limited releases may occur from TMTD used as automotive sealants in automotive manufacturing.

Current risk management activities

National level

In Canada, TMTD is registered as an active ingredient in pest control products under the name of “thiram.” The Department of Health Pest Management Regulatory Agency’s (PMRA) re-evaluation decision for thiram includes the required risk mitigation measures to protect human health and the environment from pesticidal uses of TMTD under the authority of the Pest Control Products Act.

On the basis of a re-evaluation decision by the PMRA, pest control products registered for animal repellent uses and certain seed treatment usesfootnote 4 are acceptable for continued registration with the implementation of new mitigation measures and label amendments. Health risks have not been shown to be acceptable for all other uses. Therefore, in Canada, the use of thiram has been cancelled for all foliar uses on apples, peaches, plums, strawberries, celery, and sweet potatoes (sprout root dip), and seed treatment of grasses, dry bulb onions and alfalfa grown for forage, as well as importation of these treated seeds into Canada, on-farm hopper box/seed drill seed treatment for all crops and commercial seed treatment of wheat, barley, oats, canola, mustard, rapeseed, rye, triticale (hybrid of wheat and rye) and corn. The re-evaluation decision also includes the revocation of all maximum residue limits for thiram, including those established for imports.

TMTD is described on the Cosmetic Ingredient Hotlist: Prohibited and Restricted Ingredients (Cosmetic Ingredient Hotlist) as a restricted ingredient (listed as “thiram,” under the chemical name “thiurams”), to be used only in latex products to a maximum concentration of 14%. The Cosmetic Ingredient Hotlist is an administrative tool that the Department of Health uses to communicate to manufacturers and others that certain substances may contravene the general prohibition found in section 16 of the Food and Drugs Act (FDA) or may contravene one or more provisions of the Cosmetic Regulations. The safety of chemicals used in food packaging materials is subject to the provisions of section 4(1)(a) of the FDA and Division 23 of the Food and Drug Regulations.

International level

Internationally, certain pesticide formulations containing thiram (i.e. TMTD) are listed in Annex III of the Rotterdam Convention on the Prior Informed Consent (PIC) Procedure for Certain Hazardous Chemicals and Pesticides in International Trade (Rotterdam Convention) and are therefore subject to the PIC procedure. Canada is a party to the Rotterdam Convention and has implemented risk management measures to comply with its obligations under the PIC procedure. The PIC obligations are specific to the use of TMTD in certain pesticide formulations. There is no evidence that any jurisdiction has taken specific action on the release of TMTD to the environment from solid rubber product manufacturing activities.

Canadian risk management measures that are currently in place are partially aligned with those in the United States and the European Union (EU). In the EU, TMTD is prohibited for use as a pesticide and in cosmetic products. In the United States, TMTD is permitted for use as a pesticide with restrictions, while there are no restrictions on TMTD in cosmetic products. Furthermore, TMTD is allowed to be used as a component of adhesives, or as a vulcanization accelerator in rubbers, for use in packaging, transporting, or holding food.

Summary of the screening assessment

On January 9, 2021, the ministers published a screening assessment for the Thiocarbamates Group on the (Chemical substances) website. The screening assessment was conducted to determine whether the substances meet one or more of the criteria for a toxic substance as set out in section 64 of CEPA (i.e. to determine if the substances could pose a risk to the environment or human health in Canada).

Under section 64 of CEPA, a substance is considered toxic if it is entering or may enter the environment in a quantity or concentration or under conditions that

The departments collected and considered information from multiple sources (e.g. scientific literature reviews, internal and external database searches, modelling, data from mandatory surveys issued under section 71 of CEPA and, where warranted, data from targeted follow-ups with stakeholders) to inform the screening assessment conclusion. The ecological and human health portions of this assessment have undergone external written peer review and consultation with academics and other relevant stakeholders.

The screening assessment concluded that TMTD meets the ecological criterion for a toxic substance as set out in paragraph 64(a) of CEPA and thus constitutes a risk to the environment. Below are summaries of the ecological and human health assessments.

Summary of the ecological assessment

TMTD is moderately water soluble but degrades quickly in water. Because of its low vapour pressure, it is not expected to be in the air. It is also not expected to bioaccumulate or persistfootnote 5. TMTD interacts with biological processes, resulting in lethal and developmental effects. TMTD is highly toxic to aquatic life at low levels of exposure, even if that exposure were only to last a short amount of time in the area where it was released. Effects data on aquatic, sediment, and soil organisms and on birds are summarized below.

In 2017 and 2018, limited surveillance was conducted in surface water at eight sites upstream and downstream of wastewater treatment plant discharge points, with some sites receiving wastewater from rubber products manufacturers. No samples contained TMTD above the method detection limit. In response to a CEPA section 71 survey, some companies within the rubber products, automotive, and adhesives and sealants sectors reported using TMTD to manufacture their products. Although there may be some release of this substance via raw material handling and cleaning of formulation vessels in the manufacture of adhesives and sealants, given the limited volumes, this source of release is considered to result in low exposure to TMTD in the aquatic environment.

The ecological exposure assessment focused on the solid rubber compounding process for estimating releases of TMTD to the aquatic environment. To determine if this scenario may pose an ecological risk, a risk quotient (RQ) analysis was performed to calculate the ratio between predicted environmental concentration (PEC) and predicted no-effect concentrations (PNEC). When PEC values are greater than PNEC values, there is a potential for ecological harm. The results of this analysis indicate that release of TMTD from its use in the compounding processes during the manufacturing of solid rubber products is expected to pose a risk to aquatic organisms in the environment.

The screening assessment concluded that TMTD meets the ecological criterion for a toxic substance set out in paragraph 64(a) of CEPA, but does not meet the criterion set out in paragraph 64(b). The assessment also determined that TMTD does not meet the persistence criteria or bioaccumulation criteria as set out in the Persistence and Bioaccumulation Regulations.

Summary of the human health assessment

There are no Canadian biomonitoring studies or monitoring studies of dust, air, or drinking water for TMTD. Distribution of concentrations to the environment was estimated by ChemCAN,footnote 6 which predicted low TMTD concentrations in surface water and insignificant partitioning to soil, air, or sediment. Intake estimates derived from the surface water concentrations indicated that the environment is not expected to be a significant source of human exposure to TMTD.

Exposure to TMTD is not expected from its use in automobile manufacturing, and TMTD residues are not detected in final vulcanized rubber products. Based on the low concentration of TMTD in the adhesive tape products available to consumers and the limited dermal contact area, minimal exposure is expected from such uses. Exposure to TMTD from its possible use in the manufacture of food packaging materials, if any, is likewise expected to be negligible.

According to the PMRA review on thiram, this substance is quickly absorbed, distributed, and metabolized after oral administration. It is primarily eliminated through respiration and, to a minor extent, in feces, with low distribution to tissues. The health effects of concern for thiram include developmental neurotoxicity and carcinogenicity. Thiram may also have some mutagenic and clastogenicfootnote 7 activity, but its potential for other types of genotoxicity is uncertain.

In terms of non-pesticidal uses, TMTD is primarily used as an additive to manufacture materials and products. Exposure of the general population from these uses is not expected, or exposure is expected to be low or negligible. Potential exposure to TMTD from environmental media was estimated, and the resulting health risk is not of concern, as the highest estimated intake from drinking water is well below the acceptable levelfootnote 8 set by the PMRA.

While exposure to the general population from non-pesticidal uses of TMTD is not a concern at current levels, this substance is considered to have health effects of concern (developmental neurotoxicity and carcinogenicity). Therefore, there may be a concern for human health if exposures were to increase. Options are currently being considered for follow-up activities to track changes in human exposure to TMTD.


The objective of the proposed Order Adding a Toxic Substance to Schedule 1 to the Canadian Environmental Protection Act, 1999 (the proposed Order) is to add TMTD to Schedule 1 to CEPA. This would enable the ministers to propose risk management instruments for a toxic substance under CEPA to manage potential environmental risks associated with the substance.


The proposed Order would add thioperoxydicarbonic diamide ([(H2N)C(S)]2S2), tetramethyl- to Schedule 1 to CEPA (the List of Toxic Substances).

Regulatory development


On February 3, 2018, the ministers published a summary of the draft screening assessment of the Thiocarbamates Group (which included a link to the complete draft assessment) in the Canada Gazette, Part I, for a 60-day public comment period. Comments were received from six industry stakeholders. These comments were considered in the development of the final screening assessment, published on January 9, 2021, but did not change the conclusion that TMTD meets the criterion for a toxic substance set out under paragraph 64(a) of CEPA. A table summarizing the complete set of comments received and the response to these comments is available on the (Chemical substances) website.

Industry stakeholders provided information on uses, sources and releases of TMTD in products in Canada. They also commented on the validity of the assumptions used in the exposure scenario; in their view, it is possible that these assumptions could result in overestimation of the daily quantity of TMTD used. In response, government officials stated that they considered various factors when developing a representative exposure scenario, such as variability of facilities; uses and import volumes; the logic of focusing on the compounding versus processing stages of rubber manufacturing; and average daily maximum rubber compound production capacities. The exposure scenario developed did not represent the largest capacity possible nor the locations where receiving waterbodies were the smallest. Calculations applied to this scenario reflect the non-continuous use of this substance in Canada and, therefore, in government officials’ view, the scenario likely underestimates the resulting environmental concentrations on days when TMTD is being used.

Industry stakeholders commented that a different approach should have been used to estimate emissions and recommended other emission factors. Officials indicated that the approach selected in the screening assessment provided information to estimate releases associated with raw material handling losses, which was missing in the approach recommended by stakeholders. Emission factors suggested by stakeholders were used for comparative purposes, but did not have sufficient associated information to allow extrapolation to the Canadian context; therefore, they were considered to be supporting information.

On February 3, 2018, the ministers also published a risk management scope document on the (Chemical substances) website to initiate discussions with stakeholders on the development of risk management actions. On January 9, 2021, the ministers published a risk management approach document on the (Chemical substances) website to continue discussions with stakeholders on the proposed risk management actions for this substance, such as implementing a code of practice under section 54 of CEPA and applying the significant new activity provisions under section 81 of CEPA.

Comments received on the risk management approach for TMTD will be considered during the development of risk management instruments, which would also be subject to their own consultation process.

Modern treaty obligations and Indigenous engagement and consultation

An assessment of modern treaty implications conducted in accordance with the Cabinet Directive on the Federal Approach to Modern Treaty Implementation concluded that orders adding substances to Schedule 1 to CEPA do not introduce any new regulatory requirements, and therefore, do not result in any impact on modern treaty rights or obligations. This being so, specific engagement and consultations with Indigenous Peoples were not undertaken. However, the pre-publication comment period is an opportunity for Indigenous People, as well as for all Canadians, to provide feedback on the proposed Order. For any proposed risk management measures for TMTD, the departments would assess any associated impact on modern treaty rights or obligations, and requirements for Indigenous engagement and consultations, during the development of such measures.

Instrument choice

When a substance meets one or more of the criteria for a toxic substance as set out in section 64 of CEPA, the ministers shall propose one of the following options under subsection 77(2) of CEPA:

When proposing option C, the ministers shall recommend the implementation of virtual elimination if the substance was assessed under section 74 of CEPA, and, as set out in subsection 77(4) of CEPA, if the ministers are satisfied that

The implementation of virtual elimination does not apply to TMTD, as the substance does not meet the persistence or bioaccumulation criteria in accordance with the Persistence and Bioaccumulation Regulations. Based on the available evidence, the ministers determined that it is not appropriate to manage the potential ecological risks associated with TMTD by taking no further action or adding TMTD to the Priority Substances List (option A or option B). Therefore, the ministers are recommending that TMTD be added to Schedule 1 to CEPA (option C). An order is the only available instrument to implement this recommendation.

Regulatory analysis

Benefits and costs

The addition of TMTD to Schedule 1 to CEPA would not on its own impose any regulatory requirements on businesses, and therefore, would not result in any incremental compliance costs for stakeholders or enforcement costs for the Government of Canada. The proposed Order would grant the ministers the authority to develop risk management instruments under CEPA for TMTD. The Government of Canada would consult stakeholders on any future risk management instruments before implementation and would consider their potential impacts.footnote 11

Small business lens

The small business lens analysis concluded that the proposed Order would have no associated impacts on small businesses, as it would not impose any administrative or compliance costs on businesses. For any proposed risk management measures for TMTD, the departments would assess any associated impact on small businesses during the development of such measures.

One-for-one rule

The one-for-one rule does not apply, as there is no change in administrative burden imposed on businesses. For any proposed risk management measures for TMTD, the departments would assess any associated administrative burden during the development of such measures.

Regulatory cooperation and alignment

Canada cooperates with other international organizations and regulatory agencies for the management of chemicals (e.g. the United States Environmental Protection Agency, European Chemicals Agency, and the Organization of Economic Cooperation and Development). Dustable powder pesticide formulations containing a combination of benomyl at or above 7%, carbofuran at or above 10%, and thiram (i.e. TMTD) at or above 15% are subject to the PIC procedure under the Rotterdam Convention. Canada is Party to the Rotterdam Convention and has implemented risk management measures to comply with its obligations under the PIC procedure. While the proposed Order would not on its own relate to any international agreements or obligations, it would enable the ministers to propose risk management measures that may align with actions undertaken by other jurisdictions.

Strategic environmental assessment

In accordance with the Cabinet Directive on the Environmental Assessment of Policy, Plan and Program Proposals, a strategic environmental assessment was completed for the CMP, inclusive of orders adding substances to Schedule 1 to CEPA. The assessment concluded that the CMP is expected to have a positive effect on the environment and human health.

Gender-based analysis plus

No gender-based analysis plus (GBA+) impacts have been identified for the proposed Order.

Implementation, compliance and enforcement, and service standards

As no specific risk management measures are recommended as part of the proposed Order, developing an implementation plan and a compliance and enforcement strategy, as well as establishing service standards, are not necessary at this time. For any proposed risk management measures for TMTD, the departments would assess these elements during the development of such measures.


Thomas Kruidenier
Acting Executive Director
Program Development and Engagement Division
Environment and Climate Change Canada
Gatineau, Quebec
K1A 0H3

Substances Management Information Line:
1‑800‑567‑1999 (toll-free in Canada)
819‑938‑3232 (outside of Canada)

Andrew Beck
Risk Management Bureau
Health Canada
Ottawa, Ontario
K1A 0K9
Telephone: 613‑266‑3591


Notice is given, pursuant to subsection 332(1)footnote a of the Canadian Environmental Protection Act, 1999 footnote b, that the Governor in Council, on the recommendation of the Minister of the Environment and the Minister of Health, pursuant to subsection 90(1) of that Act, proposes to make the annexed Order Adding a Toxic Substance to Schedule 1 to the Canadian Environmental Protection Act, 1999.

Any person may, within 60 days after the date of publication of this notice, file with the Minister of the Environment comments with respect to the proposed Order or a notice of objection requesting that a board of review be established under section 333 of that Act and stating the reasons for the objection. All comments and notices must cite the Canada Gazette, Part I, and the date of publication of this notice, and be sent to the Executive Director, Program Development and Engagement Division, Department of the Environment, Gatineau, Quebec K1A 0H3; (fax) 819‑938‑5212; (email)

A person who provides information to the Minister of the Environment may submit with the information a request for confidentiality under section 313 of that Act.

Ottawa, September 29, 2022

Wendy Nixon
Assistant Clerk of the Privy Council

Order Adding a Toxic Substance to Schedule 1 to the Canadian Environmental Protection Act, 1999


1 Schedule 1 to the Canadian Environmental Protection Act, 1999 footnote b is amended by adding the following in numerical order:

Coming into Force

2 This Order comes into force on the day on which it is registered.

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