Re-evaluation Decision RVD2026-03, Iodosulfuron-methyl-sodium and its associated end-use product

• Health Canada
• Healthy Environments and Consumer Safety Branch
• Pesticides Regulatory Directorate
• 6 July 2026
• ISSN: 1925-1025 (PDF version)
• Catalogue number: H113-28/2026-3E-PDF (PDF version)

Summary

Table of contents

• Re-evaluation decision for iodosulfuron-methyl-sodium and associated end-use product
• Re-evaluation decision for iodosulfuron-methyl-sodium
• Risk mitigation measures
• Implementation of the re-evaluation decision
• Next steps
• Other information
• Appendix I Registered products containing iodosulfuron-methyl-sodium in Canada

Re-evaluation decision for iodosulfuron-methyl-sodium and associated end-use product

Under the authority of the Pest Control Products Act, all registered pesticides must be re-evaluated by Health Canada to ensure that they meet current health and environmental standards and have value. The re-evaluation considers data and information from pesticide manufacturers, incident reports and other regulatory agencies, as well as comments directly related to the proposed re-evaluation decision, such as comments directed to the Science evaluation, received during public consultations. Health Canada applies internationally accepted risk assessment methods as well as current risk management approaches and policies. More details, on the legislative framework, risk assessment and risk management approach, are provided under the Evaluation approach Section in the full version of the Re-evaluation Decision RVD2026-03, Iodosulfuron-methyl-sodium and Its Associated End-use product.

Iodosulfuron-methyl-sodium is a selective sulfonylurea herbicide. It inhibits the activity of acetolactate synthase (ALS), which is the key enzyme in the biosynthesis of the branch-chain amino acids, isoleucine, leucine and valine. Although the actual sequence of phytotoxic processes is unclear, plant death results from events occurring in response to inhibition of the ALS enzyme. Iodosulfuron-methyl-sodium is used to control a range of post-emergence grassy and broadleaf weeds in field corn. It is applied once a year by field sprayer. Currently registered products containing iodosulfuron-methyl-sodium can be found in the Pesticide Product Information Database and in Appendix I.

The Proposed Re-evaluation Decision PRVD2025-10, Iodosulfuron-methyl-sodium and Its Associated End-Use Product^{Footnote 1} containing the evaluation of iodosulfuron-methyl-sodium and proposed decision, underwent a 90 day consultation period ending on 28 January 2026. PRVD2025-10 proposed continued registration of iodosulfuron-methyl-sodium and the associated end-use product in Canada, with updates to label directions and precautions to reflect the current labelling standards and improve clarity (Appendix II of RVD2026-03). Risk mitigation includes updating runoff statements to reflect current standards, adding a leaching statement and storage directions.

Written comments were received during the public consultation period conducted in accordance with section 28 of the Pest Control Products Act. However, they did not relate to the health, environmental or value assessments in PRVD2025-10. Therefore, this decision is consistent with the proposed re-evaluation decision as described in PRVD2025-10.

A reference list of information used as the basis for the proposed re-evaluation decision is included in PRVD2025-10; no further information was used in the final re-evaluation decision. Therefore, the complete reference list of all information used in this final re-evaluation decision is set out in PRVD2025-10.

This document (RVD2026-03) presents the final re-evaluation decision^{Footnote 2} for the re-evaluation of iodosulfuron-methyl-sodium, including the required amendments (risk mitigation measures) to protect human health and the environment, as well as label amendments required to bring labels to current standards. All products containing iodosulfuron-methyl-sodium that are registered in Canada are subject to this re-evaluation decision.

Re-evaluation decision for iodosulfuron-methyl-sodium

Health Canada has completed the re-evaluation of iodosulfuron-methyl-sodium. 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 iodosulfuron-methyl-sodium 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 iodosulfuron-methyl-sodium found that all uses of iodosulfuron-methyl-sodium products meets 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 new mitigation measures. Label amendments, as summarized and listed in Appendix II of RVD2026-03.

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 and/or mitigation measures, as a result of the re-evaluation of iodosulfuron-methyl-sodium, are summarized below. Refer to Appendix II of RVD2026-03.

Human health

• No label amendments are required.

Environment

To protect the environment, the following risk-reduction measures are required:

• Update runoff statement and add leaching and storage statements.

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 and up to 36-month phase-out timeline for cancelled registrations), and Information Note: Update on implementation of post-market decisions provides additional information on phase-out measures for post-market decisions that include cancellations. 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 (mitigation measures and label updates) for pest control products containing iodosulfuron-methyl-sodium is considered acceptable. These required amendments must be implemented within 24 months after the publication date RVD2026-03.

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 RVD2026-03. Accordingly, both registrants and retailers will have up to 24 months from the date of RVD2026-03 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 RVD2026-03 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

The relevant confidential test data on which the decision is based (as referenced in PRVD2025-10) are available for public inspection, upon application, in the Pesticides Regulatory Directorate's Reading Room. For more information, please contact the Pesticides Information Service.

Any person may file a notice of objection,^{Footnote 3} which must be based on scientific grounds, regarding this decision on iodosulfuron-methyl-sodium and its associated end-use product within 60 days from the date of publication of this Re-evaluation Decision through the Public Engagement Portal (Public Engagement Forms - Notice of Objection). The request for reconsideration must include the Notice of Objection form, the scientific explanation of the objection and the supporting scientific evidence in possession of the requestor that would not already be in Health Canada's possession or cite specific Health Canada documentation they wish to rely on as supporting evidence (for example, scientific reports) in the form of electronic copies of cited references. Each of the references provided or cited must be clearly associated with the objection it supports.

Failure to provide a complete package may result in the Notice of Objection being considered ineligible for further consideration by Health Canada. 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 or contact the Pesticides Information Service.

Appendix I Registered products containing iodosulfuron-methyl-sodium in Canada