Proposed Maximum Residue Limit PMRL2020-30, Halauxifen‑methyl

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The online consultation is now closed.

Pest Management Regulatory Agency
22 September 2020
ISSN: 1925-0843 (PDF version)
Catalogue number: H113-24/2020-30E-PDF (PDF version)

Under the authority of the Pest Control Products Act, Health Canada’s Pest Management Regulatory Agency (PMRA) has concluded that the addition of new preseed uses on canola varieties, flax, and mustard varieties to the label of the new end-use product Prospect Herbicide, containing technical grade halauxifen-methyl and carfentrazone, is acceptable. The specific uses approved in Canada are detailed on the label of Prospect Herbicide, Pest Control Products Act Registration Number 33635.

The evaluation of this halauxifen-methyl application indicated that the end-use product has value and the human health and environmental risks associated with the new uses are acceptable.

Before registering a pesticide for food use in Canada, the PMRA must determine the quantity of residues that are likely to 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. This quantity is then legally established as a maximum residue limit (MRL). An MRL applies to the identified raw agricultural food commodity as well as to any processed food product that contains it, except where separate MRLs are specified for the raw agricultural commodity and a processed product made from it.

Consultation on the proposed MRL for halauxifen-methyl is being conducted via this document (see Next Steps). A summary of the field trial data used to support the proposed MRL can be found in Appendix I.

For carfentrazone, the previously established MRLs of 0.1 ppm in/on rapeseeds (canola), flaxseeds, and mustard seeds (oilseed type) are sufficient to cover residues resulting from this new use and is therefore unaffected by this MRL action.

To comply with Canada’s international trade obligations, consultation on the proposed MRL is also being conducted internationally by notifying the World Trade Organization, as coordinated by the Canada's Notification Authority and Enquiry Point.

The proposed MRL, to be added to the MRLs already established for halauxifen-methyl, is as follows.

Table 1: Proposed Maximum Residue Limit for halauxifen-methyl
Common name Residue definition MRL (ppm)Table 1: Tablenote 1 Food commodity

Methyl 4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)-2-pyridinecarboxylate

0.01 Rapeseeds (crop subgroup 20A) (revised)

Table 1: Tablenote 1

Table 1: Tablenote 1

ppm = parts per million

Return to Table 1: Footnote 1 referrer

MRLs are proposed for each commodity included in the listed crop groupings in accordance with the Residue Chemistry Crop Groups webpage in the Pesticides section of the website.

MRLs established in Canada may be found using the Maximum Residue Limit Database on the Maximum Residue Limits for Pesticides 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

MRLs may vary from one country to another for a number of reasons, including differences in pesticide use patterns and the locations of the crop field trials used to generate residue chemistry data.

Table 2 compares the MRL proposed for halauxifen-methyl in Canada with the corresponding American tolerance and Codex MRLsFootnote 1. American tolerances are listed in the Electronic Code of Federal Regulations, 40 CFR Part 180, by pesticide. Currently, there are no Codex MRLs listed for halauxifen-methyl in or on any commodity on the Codex Alimentarius Pesticide Index webpage.

Table 2: Comparison of Canadian MRL, American Tolerance and Codex MRL (where different)
Food commodity Canadian MRL (ppm) American Tolerance (ppm) Codex MRL

Rapeseeds (crop subgroup 20A) (revised)

0.01 Not established Not established

Next steps

The PMRA invites the public to submit written comments on the proposed MRL for halauxifen-methyl up to 75 days from the date of publication of this document. Please forward your comments to Publications. The PMRA will consider all comments received before making a final decision on the proposed MRL. Comments received will be addressed in a separate document linked to this PMRL. The established MRL will be legally in effect as of the date that they are entered into the Maximum Residue Limit Database.

Appendix I

Summary of field trial data used to support the proposed maximum residue limit

Residue data for halauxifen-methyl in rapeseed were submitted to support the domestic use of Prospect Herbicide on canola, flax and mustard. In addition, previously reviewed residue data from field trials conducted in/on soybeans were also reassessed to determine the potential for concentration of residues of halauxifen-methyl into processed commodities.

Maximum residue limit

The recommendation for a maximum residue limit (MRL) for halauxifen-methyl was based upon the submitted field trial data, and the guidance provided in the OECD MRL Calculator. Table A1 summarizes the residue data used to calculate the proposed MRL for rapeseeds (crop subgroup 20A).

Table A1: Summary of Field Trial and Processing Data Used to Support the MRL
Commodity Application method/
Total application rate
(g a.i./ha/season)Table A-1: Footnote 1
Preharvest interval (days) Lowest average field trial residues (ppm) Highest average field trial residues (ppm) Experimental processing factor


109–251 <0.01 <0.01 No quantifiable residues observed at exaggerated rates in the soybean processing study.Table A-1: Footnote 2
Table A1 Footnote 1

g a.i./ha = grams of active ingredient per hectare

Table A1 Return to footnote 1 referrer

Table A1 Footnote 2

Soybean processing data was extended to rapeseed, as per the OECD Guidelines for the Testing of Chemicals – Test No. 508.

Table A1 Return to footnote 2 referrer

Following the review of all available data, MRLs as proposed in Table 1 is recommended to cover residues of halauxifen-methyl. Residues of halauxifen-methyl in these crop commodities at the proposed MRL will not pose an unacceptable risk to any segment of the population, including infants, children, adults and seniors.


Footnote 1

The Codex Alimentarius Commission is an international organization under the auspices of the United Nations that develops international food standards, including MRLs.

Return to footnote 1 referrer

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