Chemical substances in Batch 4 of the Challenge

On this page

• Summary of Batch 4 substances and publications
• Timelines
• Risk management action milestones
• Adding substances to Schedule 1
• Deleting substances from Schedule 1
• Significant New Activity (SNAc) provisions
  • Applying SNAc provisions
  • Varying the requirements under the SNAc provisions
  • Rescinding the requirements under the SNAc provisions
• Benzenamine, N-phenyl-, reaction products with styrene and 2,4,4-trimethylpentene (BNST): CAS RN 68921-45-9
• Final screening assessments and risk management approaches
• Draft screening assessments and risk management scopes
• Information gathering
  • 2007 Mandatory survey – section 71 notice

Summary of Batch 4 substances and publications

Risk management action milestones

The risk management action milestones table outlines the risk management actions that were proposed for each chemical substance in this batch of the Chemical Management Plan's (CMP) Challenge Initiative that met the criteria of section 64 of CEPA. These proposed risk management actions were published in the risk management approaches for these substances. For the complete wording of these proposed actions, please refer to the risk management approaches.

Adding substances to Schedule 1

Three substances in this batch have been added to Schedule 1 to CEPA. One substance, BNST, was subsequently deleted.

• Final order adding diethyl sulfate (CAS RN 64-67-5), dimethyl sulfate (CAS RN 77-78-1) and BNST (CAS RN 68921-45-9): Canada Gazette, Part II: Vol. 145, No. 5 - March 2, 2011

Deleting substances from Schedule 1

In October 2020, BNST was deleted from Schedule 1 to CEPA.

• Order deleting BNST: Canada Gazette, Part II: Vol. 154, No. 22 – October 28, 2020

BNST was added to Schedule 1 to CEPA as a result of the 2009 assessment of Batch 4 of the CMP's Challenge Initiative, where it was found to meet the criteria set out in section 64(a) of CEPA. New information on BNST was obtained following the 2009 assessment; therefore, BNST was re-assessed in the December 2017 Final Screening Assessment for Substituted Diphenylamines, where the Government of Canada concluded that BNST did not meet the criteria under section 64 of CEPA. Based on the results of the final screening assessment, the Government of Canada has deleted BNST from Schedule 1 to CEPA.

Significant New Activity (SNAc) provisions

View the SNAc publications under CEPA. Orders are subject to potential amendments under the SNAc Review.

Applying Significant New Activity provisions

In January 2013, an order amending the DSL to apply the SNAc provisions of CEPA to diethyl sulfate (CAS RN 64-67-5) and dimethyl sulfate (CAS RN 77-78-1) was published:

• Canada Gazette, Part II: Vol. 147, No. 3 - January 30, 2013

In August 2009, an order amending the DSL to apply the SNAc provisions of CEPA to 5 substances was published:

• Canada Gazette, Part II: Vol. 143, No. 17 - August 19, 2009

For additional guidance on submitting information required as part of SNAc notifications, please see the Guidance document for the New Substances Notification Regulations (Chemicals and Polymers).

Varying the requirements under the SNAc provisions

In March 2026, an order amending the DSL to vary the requirements under the SNAc provisions of CEPA for four substances in this batch (CAS RNs 1154-59-2, 1176-74-5, 64325-78-6, and 70776-86-2) was published in the Canada Gazette, Part II: Vol. 160, No. 6 – March 25, 2026. The amendments are an outcome of the SNAc Review.

In January 2017, a notice of intent to amend the DSL to vary the requirements under the SNAc provisions of CEPA for diethyl sulfate (CAS RN 64-67-5) and dimethyl sulfate (CAS RN 77-78-1) was published in the Canada Gazette, Part I: Vol. 151, No. 2 - January 14, 2017 for a 60-day public comment period. The proposed amendments are an outcome of the SNAc Review. The DSL amendments do not come into force until the final order is published in the Canada Gazette, Part II. Any current requirements under the SNAc provisions remain in effect until then.

Rescinding the requirements under the SNAc provisions

In August 2024, an order rescinding the requirements under the SNAc provisions of CEPA for amines, C18-22-tert-alkyl, ethoxylated (CAS RN 68443-10-7) was published in the Canada Gazette, Part II, Vol. 158, No.17 – August 14, 2024. This substance was subject to the SNAc provisions as a result of the 2009 screening assessment of substances in this batch. Since then, it was included in the High Hazard Not in Commerce Substances SNAc Review Group, under the SNAc Review. That review led to the recommendation that the requirements under the SNAc provisions for this substance be rescinded.

In July 2019, a notice of intent to rescind the requirements under the SNAc provisions of CEPA for amines, C18-22-tert-alkyl, ethoxylated (CAS RN 68443-10-7) was published in the Canada Gazette, Part I: Vol. 153, No. 30 - July 27, 2019 for a 60-day public comment period. This substance was subject to the SNAc provisions as a result of the 2009 screening assessment of substances in this batch. Since then, it was included in the High Hazard Not in Commerce Substances SNAc Review Group, under the SNAc Review. That review led to the recommendation that the requirements under the SNAc provisions for this substance be rescinded. Furthermore, the substance is not currently in commerce in Canada. Current SNAc requirements remain in effect until the final order is published in the Canada Gazette, Part II.

Benzenamine, N-phenyl-, reaction products with styrene and 2,4,4-trimethylpentene (BNST): CAS RN 68921-45-9

BNST is an SDPA that was assessed in 2009. Subsequent to the publication of that assessment, other SDPAs were identified for assessment based on their potential risks to the environment and their similarity with BNST. Significant new information also became available regarding the inherent toxicity and bioaccumulation potential of these substances, which brought into question the validity of the previous assessment conclusion for BNST. As a result, BNST has been re-assessed with these other SDPAs as part of the Substance Groupings Initiative of the CMP.

In December 2017, the Final Screening Assessment for Substituted Diphenylamines was released and the related notice was published in the Canada Gazette, Part I: Vol. 151, No. 49 - December 9, 2017. The final screening assessment concluded that none of the 14 SDPAs assessed pose a risk to the environment or to human health and, therefore, do not meet any of the criteria under section 64 of CEPA. This conclusion applies to BNST, which was considered among the 14 SDPAs, and which had previously been found to meet the criteria set out in section 64 (a) of CEPA in its 2009 screening assessment. Based on results of the final screening assessment, the Government of Canada has deleted BNST from Schedule 1 to CEPA. The Prohibition of Certain Toxic Substances Regulations, 2012 were also amended to remove the restrictions on BNST.

In December 2016, the Draft Screening Assessment for Substituted Diphenylamines was published for a 60-day public comment period. Given the proposed change in conclusion for BNST and potential implications to the regulatory requirements for this substance, the Government of Canada also published a Consultation Document on the Proposed Approach Regarding Future Regulatory Amendments for BNST for a 60-day public comment period.

Final screening assessments and risk management approaches

In August 2009, the final screening assessments for this batch were released and the related notices were published in the Canada Gazette, Part I: Vol. 143, No. 31 - August 1, 2009.

The final screening assessments concluded that three substances in this batch (CAS RNS 64-67-5, 77-78-1, and 68921-45-9) meet one or more criteria in section 64 of CEPA. The Government added these substances to Schedule 1 to CEPA. BNST was subsequently removed from Schedule 1. Proposed risk management approaches were also released on this date for the substances in this batch which met the criteria in section 64 of CEPA.

For the remaining two substances in this batch (CAS RNs 75-28-5 and 106-97-8), the assessment that was conducted evaluated the exposure to, and potential risk from, 1,3-butadiene in isobutane containing 1,3-butadiene and in butane containing 1,3-butadiene. It was concluded that exposure to 1,3-butadiene from the uses of butane containing 1,3-butadiene and isobutane containing 1,3-butadiene should be considered in relation to the ongoing risk management of 1,3-butadiene conducted under CEPA.

A screening assessment of the substances isobutane and butane, in the absence of 1,3-butadiene, was later undertaken in January 2017 as part of a group of substances known as short-chain alkanes.

Draft screening assessments and risk management scopes

New information was received from industry or interested stakeholders for each of the 18 substances in this batch. In January 2009, the draft screening assessments were released and the related notices were published in the Canada Gazette, Part I: Vol. 143, No. 4 - January 24, 2009. Risk management scopes were also released in conjunction with these publications.

Information gathering

2007 Mandatory survey – section 71 notice

In November 2007, a notice was published in Canada Gazette, Part I: Vol. 141, No. 46 - November 17, 2007 under section 71 of CEPA. This section 71 notice applied to all 18 substances in this batch.