Proposed Maximum Residue Limit PMRL2018-30, 2,4-D

Notice to the reader:

This consultation is now closed.

Pest Management Regulatory Agency
21 August 2018
ISSN: 1925-0843 (PDF version)
Catalogue number: H113-24/2018-30E-PDF (PDF version)

Under the authority of the Pest Control Products Act, Health Canada’s Pest Management Regulatory Agency (PMRA) is proposing to establish a maximum residue limit (MRL) for 2,4-D on undelinted cotton seeds to permit the import and sale of foods containing such residues.

2,4-D is a herbicide currently registered in Canada for use on various commodities.

The PMRA must determine the quantity of residues that are likely to remain in or on the imported food commodity when 2,4-D is used according to label directions in the exporting country, and that such residues will not be a concern to human health. This quantity is then legally established as a maximum residue limit (MRL) on the corresponding imported commodity. 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 2,4-D 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.

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 Canada’s Notification Authority and Enquiry Point.

The proposed MRL, to be added to the MRLs already established for 2,4-D, is as follows.

Table 1 Proposed Maximum Residue Limit for 2,4-D

Common Name

Residue Definition

MRL (ppm)Footnote 1

Food Commodity


(2,4-dichlorophenoxy) acetic acid


Undelinted cotton seeds

Footnote 1

ppm = parts per million

Return to footnote 1 referrer

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

The MRL proposed for 2,4-D in Canada is the same as the corresponding American tolerance as listed in the Electronic Code of Federal Regulations, 40 CFR Part 180, by pesticide. Currently, there is no Codex MRLFootnote 1 listed for 2,4-D on this commodity on the Codex Alimentarius Pesticide Index webpage.

Next Steps

The PMRA invites the public to submit written comments on the proposed MRL for 2,4-D 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 2,4-D in cotton were submitted to support the maximum residue limit on imported cotton seeds. Supporting analytical methodology and freezer storage stability data were also reviewed. In addition, a processing study in treated cotton seed was reviewed to determine the potential for concentration of residues of 2,4-D into processed commodities.

Maximum Residue Limit

The recommendation for a maximum residue limit (MRL) for 2,4-D was based upon the residues observed in the crop commodity treated according to label directions in the exporting country, and the guidance provided in the OECD MRL Calculator. Table A1 summarizes the residue data used to calculate the proposed MRL for imported cotton seeds.

Table A1 Summary of Field Trial and Processing Data Used to Support the MRL


Application Method/ Total Application Rate
(g a.i./ha)Footnote 1

Preharvest Interval (days)

Lowest Average Field Trial Residues

Highest Average Field Trial Residues

Experimental Processing Factor

Undelinted cotton seeds

Pre- and post-emergent ground application /


< 0.01


Cottonseed oil:
< 1×

Footnote 1

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

Return to footnote 1 referrer

Following the review of all available data, an MRL as proposed in Table 1 is recommended to cover residues of 2,4-D. Residues of 2,4-D in imported cotton commodities at the proposed MRL will not pose an unacceptable health 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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