Proposed re-evaluation decision PRVD2025-06, Potassium bicarbonate and its associated end-use products

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Pest Management Regulatory Agency
10 June 2025
ISSN: 1925-0967 (PDF version)
Catalogue number: H113-27/2025-6E-PDF (PDF version)

Summary

Table of contents

• Proposed re-evaluation decision for Potassium Bicarbonate and its associated end-use products
• Proposed risk-reduction measures
• Proposed re-evaluation decision
• Next steps
• Other information
• Additional scientific information

Proposed re-evaluation decision for potassium bicarbonate and its 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 continue to meet health and environmental standards and continue to have value. The re-evaluation considers data and information from pesticide manufacturers, incident reports, and other regulatory agencies. Health Canada applies internationally accepted risk assessment methods, risk management approaches and policies to all re-evaluations.

This document (Proposed Re-evaluation Decision PRVD2025-06, Potassium Bicarbonate and Its Associated End-use Products) presents the proposed re-evaluation decision for potassium bicarbonate, including any proposed amendments (risk mitigation measures) to protect human health and the environment, as well as the Science evaluation on which the proposed decision is based.

Potassium bicarbonate is a contact fungicide that acts by inhibiting fungus mycelium development following spore germination. Potassium bicarbonate is registered for control or suppression of powdery mildew on a wide range of greenhouse and field crops including certain ornamentals, vegetables, fruits, herbs and spices, cannabis grown in greenhouses or other enclosed growing structures and field-grown cannabis and industrial hemp. It is also registered for suppression of Botrytis grey mold on grapes and partial suppression of primary infections of apple scab in orchards. Currently registered products containing potassium bicarbonate are listed in Appendix I of PRVD2025-06.

When the proposed label directions are followed, these products are shown to have value in providing a pest management solution, and potential risks to human health (occupational, dietary, residential and bystander) and the environment (aquatic and terrestrial organisms) are considered to be acceptable. As a result of re-evaluation, application of potassium bicarbonate is permitted for use only during the vegetative stage of growth for cannabis and industrial hemp (for smoking and vaping). Additional label updates are proposed to improve clarity and to meet current labelling standards.

Proposed risk-reduction measures

Registered pesticide product labels include specific directions for use. Directions include risk mitigation measures to protect human health and the environment, and to ensure the product has acceptable value, which must be followed by law. The proposed label amendments including any revised/updated label statements and/or mitigation measures, as a result of the re-evaluation of potassium bicarbonate, are summarized below. Refer to Appendix II of PRVD2025-06 for details.

Human health

• Update personal protective equipment, restricted-entry interval, and spray drift statement to meet current standards.
• Update precautionary statements to include respirator and ventilation requirements for all the labelled crops treated in enclosed areas using ultra-low volume method of application.
• Limit the application of MilStop to the vegetative stage only for cannabis grown in greenhouses or other enclosed growing structures as well as for cannabis grown outdoors and industrial hemp grown outdoors (for smoking and vaping).

Environment

• Label amendments to meet current standards including disposal statement and use directions (spray drift).

Value

• Update general statements on all product labels to improve clarity and meet current standards (for example, replace guarantee with active ingredient).

Proposed re-evaluation decision

Under the authority of the Pest Control Products Act, and based on an evaluation of currently available scientific information, in accordance with subsection 16(6) of the Pest Control Products Act, under section 21 of the Pest Control Products Act.

This document is subject to a 90-day public consultation period.^{Footnote 1} Comments on the proposed decision can be submitted to the PMRA through PMRA Publications, or the Public Engagement Portal (Public Engagement Forms - Consultation Comment). All products containing potassium bicarbonate that are registered in Canada are subject to this proposed re-evaluation decision.

Refer to Appendix I of PRVD2025-06 for details on specific products impacted by this proposed decision.

Next steps

Upon publication of this proposed re-evaluation decision, the public, including the registrants and stakeholders are encouraged to submit comments during the 90-day public consultation period.

Health Canada will accept written comments on this proposal up to 90 days from the date of publication of this document. Before making a re-evaluation decision on potassium bicarbonate under section 21 of the Pest Control Products Act, written comments received during the consultation period will be taken into consideration, and a science-based approach will be applied in making a final decision on potassium bicarbonate.

In accordance with subsection 28(5) of the Pest Control Products Act, Health Canada will then publish a final re-evaluation decision document, which will include the decision,^{Footnote 2} the reasons for it, a summary of the comments received on the proposed re-evaluation decision, and Health Canada’s response to these comments.

Other information

The relevant confidential test data on which the proposed decision is based are available for public inspection upon application, in the PMRA’s Reading Room. For more information or if you have questions, please contact the PMRA’s Pest Management Information Service.

Additional scientific information

No additional scientific data are being requested at this time.