Proposed Maximum Residue Limit PMRL2025-15, Metamitron
Pest Management Regulatory Agency
18 August 2025
ISSN: 1925-0843 (PDF version)
Catalogue number: H113-24/2025-15E-PDF (PDF version)
Table of contents
- Purpose of consultation
- Dietary health assessment
- Proposed MRLs
- International situation and trade implications
- How to get involved
Purpose of consultation
Maximum residue limits (MRLs)Footnote 1 are being proposed for the pesticide metamitron as part of the following applications for Canadian use, under submission numbers 2021-6621, 2021-6706 and 2022-0013.
Under the authority of the Pest Control Products Act, Health Canada's Pest Management Regulatory Agency (PMRA) is proposing acceptability of the uses requested under the above-noted applications to register the technical grade metamitron and the end-use products Brevis 150 SC and Brevis 15 SG for new uses on apples and pears in Canada, as a plant growth regulator.
The evaluation of these metamitron applications indicated that the end-use products have value, and the human health and environmental risks associated with their proposed uses are acceptable. Details regarding these applications can be found in Proposed Registration Decision PRD2025-05, Metamitron, Brevis 150 SC, and Brevis 15 SG, posted to the Pesticides and pest management section of the Canada.ca website on August 8 2025. Dietary risks from the consumption of foods listed in Table 1 were shown to be acceptable when metamitron is used according to the supported label directions. Therefore, foods containing residues resulting from these uses are safe to eat, and MRLs are being proposed as a result of this assessment.
Dietary health assessment
In assessing the risk of a pesticide, Health Canada combines information on pesticide toxicity with information on the degree and duration of dietary exposure to the pesticide residue from food. The risk assessment process involves four distinct steps:
- Identifying the toxicology hazards posed by the pesticide;
- Determining the "acceptable dietary level" for Canadians (including all vulnerable populations), which is protective of adverse health effects;
- Estimating human dietary exposure to the pesticide from all applicable sources (domestic and imported commodities); and
- Characterizing health risk by comparing the estimated human dietary exposure to the acceptable dietary level.
Before registering a pesticide for food use in Canada, Health Canada must determine the quantity of residues that could remain in or on the food when the pesticide is used according to label directions and that such residues will not be a concern to human health (step 3 and step 4). If estimated human exposure is less than or equal to the acceptable level (developed in step 2), Health Canada concludes that consuming residues resulting from use according to approved label directions is not a health concern. The proposed MRL is then subject to consultation to legally specify it as an MRL. An MRL applies to the identified raw agricultural food commodity, as well as to any processed food product that contains it, except for certain instances where different MRLs are specified for the raw agricultural commodity and its processed product(s).
Consultation on the proposed MRLs for metamitron is being conducted via this document and PRD2025-05. Health Canada invites the public to submit written comments on the proposed MRLs for metamitron in accordance with the process outlined in the How to get involved Section of this document, and with the process outlined in PRD2025-05.
To comply with Canada's international trade obligations, consultation on the proposed MRLs is also being conducted internationally by notifying the World Trade Organization, as coordinated by Canada's Notification Authority and Enquiry Point.
Proposed MRLs
The proposed MRLs for metamitron are summarized in Table 1.
| Common name | Residue definition | MRL (ppm)Table 1 footnote 1 | Food commodity |
|---|---|---|---|
| Metamitron | 4-amino-3-methyl-6-phenyl-1,2,4-triazin-5(4H)-one | 0.01 | Apples, pears |
MRLs established in Canada may be found using the Maximum Residue Limit Database on the Maximum residue limits, human health, and food safety webpage. The database allows users to search for established MRLs, regulated under the Pest Control Products Act, both for pesticides or for food commodities.
International situation and trade implications
As per Table 2, the MRLs proposed for metamitron in Canada are the same as corresponding tolerances in the United States (U.S.) as listed in the Electronic Code of Federal Regulations, 40 CFR Part 180, by pesticide. Currently, there are no Codex MRLsFootnote 2 listed for metamitron in or on any commodity on the Codex Alimentarius Pesticide Index webpage.
| Food commodity | Proposed Canadian MRL (ppm) | Established U.S. tolerance (ppm) | Established Codex MRL (ppm) |
|---|---|---|---|
| Apples, pears | 0.01 | 0.01 | Not established |
How to get involved
Health Canada invites the public to submit written comments on the proposed MRLs for metamitron up to 75 days from the date of publication of this document (by 1 November 2025). Please forward your comments to the PMRA Publications Section. Health Canada will consider all comments received and a science-based approach will be applied in making a final decision on the proposed MRLs. Comments received will be addressed in a response to comments document found in Pesticides and pest management consultations. The established MRLs will be legally in effect as of the date that they are entered into the Maximum Residue Limit Database.