Re-evaluation Decision RVD2025-03, 3-Methyl-2-cyclohexen-1-one and its associated end-use products

• Pest Management Regulatory Agency
• 23 June 2025
• ISSN: 1925-1025 (PDF version)
• Catalogue number: H113-28/2025-3E-PDF (PDF version)

Summary

Table of contents

• Re-evaluation decision for 3-methyl-2-cyclohexen-1-one and associated end-use products
• Re-evaluation decision for methylcyclohexenone
• Risk mitigation measures
• Implementation of the re-evaluation decision
• Amendment timeframe
• Next steps
• Other information
• Appendix I Registered products containing methylcyclohexenone in Canada

Re-evaluation decision for 3-methyl-2-cyclohexen-1-one and associated end-use products

Under the authority of the Pest Control Products Act, all registered pesticides must be re-evaluated by Health Canada's Pest Management Regulatory Agency (PMRA) to ensure that they meet current health and environmental standards and have value. The re-evaluation considers data and information from pesticide manufacturers, published scientific reports and other regulatory agencies, as well as comments received during public consultations. Health Canada applies internationally accepted risk assessment methods as well as current risk management approaches and policies.

This document (Re-evaluation Decision RVD2025-03, 3-Methyl-2-cyclohexen-1-one and its associated end-use products) presents the final re-evaluation decision^{Footnote 1} for the re-evaluation of 3-methyl-2-cyclohexen-1-one (also referred to as methylcyclohexenone), including the response to comments received, and the required label updates. All products containing 3-methyl-2-cyclohexen-1-one regulated under the Pest Control Products Act in Canada are subject to this re-evaluation decision.

Methylcyclohexenone is an anti-aggregation pheromone (semiochemical) registered as an insect repellent to deter Douglas-fir beetle, Dendroctonus pseudotsugae, and spruce beetle, Dendroctonus rufipennis, from attacking Douglas-fir trees and spruce trees, respectively. Methylcyclohexenone is a naturally occurring pheromone produced by beetles (Dendroctonus sp.), and released after they successfully attack a host tree.

Currently registered products containing methylcyclohexenone can be found in the Pesticide Product Information Database and in Appendix I. The Proposed Re-evaluation Decision PRVD2024-05, 3-Methyl-2-cyclohexen-1-one and its Associated End-use Products^{Footnote 2} containing the evaluation of methylcyclohexenone and proposed decision, underwent a 90 day consultation period ending on 23 December 2024. PRVD2024-05 proposed continued registration of methylcyclohexenone products in Canada, with updates to label directions and precautions to reflect the current labelling standards and to improve clarity (Appendix IV of the full version of RVD2025-03).

Health Canada received comments during the public consultation. Commenters are listed in Appendix II of RVD2025-03. The comments are summarized in Appendix III of RVD2025-03 along with the responses by Health Canada. The comments did not result in changes to the proposed re-evaluation decision as described in PRVD2024-05. A reference list of information used as the basis for the proposed re-evaluation decision is included in PRVD2024-05.

Re-evaluation decision for methylcyclohexenone

Health Canada has completed the re-evaluation of methylcyclohexenone. Under the authority of the Pest Control Products Act, Health Canada has completed all required evaluations and consultations and has determined that the registration of products containing methylcyclohexenone is required to be amended, in accordance with paragraph 21(2)(a) of the Pest Control Products Act. An evaluation of available scientific information respecting the health and environmental risks and value of methylcyclohexenone found that all uses of methylcyclohexenone products meet current standards for protection of human health and the environment and have acceptable value when used according to the amended conditions of registration which includes updates to standard label statements to reflect the current labelling standards and for clarity. Label amendments, as summarized below and listed in Appendix IV of RVD2025-03, are required.

Risk mitigation measures

Registered pesticide product labels include specific directions for use. Directions include risk mitigation measures to protect human health and the environment and must be followed by law. The required amendments, including any revised/updated label statements, as a result of the re-evaluation of methylcyclohexenone, are summarized below. Refer to Appendix IV of RVD2025-03 for details.

Label improvements to meet current standards - Human health

• Update personal protective equipment to current standards.

Label improvements to meet current standards - Environment

• Update environmental precautions for aquatic environment and disposal.

Implementation of the re-evaluation decision

Regulatory Directive DIR2018-01, Policy on Cancellations and Amendments Following Re-evaluation and Special Review provides information and general timelines regarding the implementation of post-market decisions, (for example, up to 24-month timeline for label amendments). The post-market decision considers potential health and environmental risks regarding the use of the pest control product, and its value, when establishing the implementation timelines.

Amendment timeframe

The implementation timeline of 24 months for the required amendments (label updates) for pest control products containing methylcyclohexenone is considered acceptable. These required amendments must be implemented within 24 months after the publication date of this decision document.

Refer to Appendix I for details on specific products impacted by this decision.

Next steps

To comply with this decision, the required amendments (mitigation measures and label updates) must be implemented on all product labels no later than 24 months after the publication date of this decision document. Accordingly, both registrants and retailers will have up to 24 months from the date of this decision document to transition to selling the product with the newly amended labels. Similarly, users will also have the same 24-month period from the date of this decision document to transition to using the newly amended labels, which will be available on the Public Registry.

Refer to Appendix I for details on specific products impacted by this decision.

Other information

Any person may file a notice of objection^{Footnote 3} regarding this decision on methylcyclohexenone and its associated end-use products within 60 days from the date of publication of this Re-evaluation Decision. For more information regarding the basis for objecting (which must be based on scientific grounds), please refer to the Pesticides and Pest Management Section of the Canada.ca website (Public Engagement Portal - Public Engagement Forms - Notice of Objection) or contact PMRA's Pest Management Information Service.

The relevant confidential test data on which the decision is based (as referenced in PRVD2024-05) are available for public inspection, upon application, in PMRA's Reading Room. For more information, please contact the PMRA's Pest Management Information Service.

Appendix I Registered products containing methylcyclohexenone in Canada