Response to comments and rationale for revisions

Release guidelines for chemicals used in the rubber product manufacturing sector

On March 22, 2025, Environment and Climate Change Canada (ECCC) published the proposed Release guidelines for chemicals used in the rubber product manufacturing sector (Guidelines). A 60-day public comment period followed publication. These Guidelines include:

• BENPAT (1,4-benzenediamine, N,N’-mixed phenyl and tolyl derivatives)
• TMTD (Thioperoxydicarbonic diamide ([(H₂N)C(S)]₂S₂), tetramethyl-)

ECCC presents below a summary of comments received and its responses to these comments. ECCC also explains the rationale for revisions made to the Guidelines following the 60-day comment period.

Comments received during the 60-day public comment period

1. TMTD effluent analysis

One industry stakeholder requested a list of Canadian laboratory vendors capable of conducting TMTD effluent analysis.

Response: As indicated in appendix 1 of the Guidelines:

• An analytical method for detecting TMTD in industrial effluents is not available. This is because TMTD degrades quickly in wastewater
• As a result, ECCC does not require sampling for TMTD
• Instead, ECCC estimates the concentration of TMTD in industrial effluent. Calculations are provided in the annual evaluation report (appendix 3 of the Guidelines)

2. BENPAT effluent analysis

One industry stakeholder requested a list of Canadian laboratory vendors capable of conducting BENPAT effluent analysis.

Response: ECCC does not maintain a list of accredited laboratories that can perform BENPAT analysis. However, Pacific Rim Laboratories developed the laboratory method for BENPAT listed in appendix 4 of the Guidelines. This laboratory can conduct the analysis following the procedures outlined in section 6 of the Guidelines.

3. Concerns with animal testing

One Canadian citizen raised concerns that effluent sampling under the Guidelines could result in animal testing. Their concerns focused on acute lethality tests involving fish and daphnia shrimp. However, the Guidelines do not mention these tests directly.

They urged ECCC to eliminate all forms of animal testing in environmental monitoring and proposed various non-animal alternatives.

Response: The Guidelines do not require or recommend any form of animal testing for participation. These Guidelines focus on managing chemical releases through pollution prevention and monitoring chemical concentrations using analytical chemistry techniques.

4. Restrictions on the use of BENPAT and TMTD as rubber vulcanization accelerators in automotive parts

One industry stakeholder commented on the Guidelines with the following points:

• BENPAT and TMTD are important process chemicals used as vulcanization accelerators in automotive rubber parts. These substances help extend product lifespan and improve safety.
• The stakeholder asked that ECCC avoid restricting the use of BENPAT and TMTD in automotive and durable consumer goods. They urged ECCC to consider how regulations might affect their release during manufacturing.

Response: The Guidelines do not restrict the use of specific chemicals like BENPAT or TMTD within products. Instead, they focus on managing and controlling releases into the aquatic environment from manufacturing facilities. Key measures include:

• Pollution prevention strategies
• Wastewater treatment options

Through these measures, ECCC aims to protect the environment. The use of important process chemicals will be allowed to continue if appropriate controls are in place during manufacturing.

Rationale for notable revisions to the Guidelines since ECCC published the proposed version

Addition of on-site and off-site wastewater treatment rates

Appendix 3 of the proposed Guidelines included a single efficiency value (R) for the wastewater treatment system efficiency. In the final Guidelines, this value is now broken down into two distinct variables:

• RR_on: represents the on-site wastewater treatment system removal rates (fraction)
• RR_off: represents the off-site wastewater treatment system removal rates (fraction)

Rationale: ECCC includes on-site (RR_on) and off-site (RR_off) wastewater treatment rates in appendix 3 of the Guidelines. These rates help estimate the quantity of the substance of concern that remains in industrial effluent after treatment.

Key updates in the final Guidelines:

• ECCC uses RR_on when the facility treats its own effluent
• ECCC uses RR_off when the facility sends its effluent to an external wastewater treatment plant
• Each variable has its own set of default assumptions based on the level of treatment (primary or secondary)
• The updated calculation improves how ECCC accounts for the removal of substances of concern during wastewater treatment