Consultation on the proposed re-evaluation decision of S-metolachlor and R-enantiomer and its associated end-use products, PRVD2024-01

Current status: Open

Opened on 29 February 2024 and will close for consultation on 29 May 2024

Health Canada is consulting the public and seeking your feedback on the proposed re-evaluation decision to continue allowing most of the current uses of S-metolachlor and R-enantiomer with updated risk reduction measures.

What is S-metolachlor and R-enantiomer

S-metolachlor and R-enantiomer (from now on referred to as S-metolachlor) is a herbicide registered for use in Canada. It provides broad control over weeds including broadleaved weeds (such as dandelions and thistles), annual grasses and yellow nutsedge. S-metolachlor is registered for use on:

S-metolachlor is applied once per year using ground equipment, like a ground boom field sprayer, and can be applied to fields when crops are in the very early stages of development or before they are planted.

Currently, S-metolachlor is only used in commercial class products. Commercial class products are restricted to the commercial activities that are indicated on the product label. These products are not available to the general public for use in and around the home.

What is a re-evaluation

Re-evaluations are cyclical reviews that look at all aspects of a pesticide to determine if the pesticide meets current health, environment and value requirements. Re-evaluations are conducted using modern assessment techniques and current scientific information. If Health Canada's scientific information requirements or evaluation procedures change, pesticides may also be re-evaluated.

What is the proposed re-evaluation decision

Health Canada proposes to continue allowing most of the current uses of S-metolachlor with updated risk reduction measures to protect people and the environment. Health Canada also proposes to cancel the use of S-metolachlor in impregnated granular fertilizers. Impregnated granular fertilizers are small, solid pellets of fertilizer that are coated or infused with pesticides. This cancellation is because the only granular fertilizer product containing S-metolachlor is co-formulated with the pesticide atrazine (product registration number 29358) and would align with recommendations in the proposed special review for atrazine (PSRD2023-01). In the proposed special review for atrazine, the co-formulated product is proposed to be cancelled because it does not meet the requirements for the protection of human health.

Risk-reduction measures are legally mandated actions that must be taken by growers and commercial users of S-metolachlor to protect human health and the environment. To protect human health, the addition of the following risk reduction measures are proposed:

To protect the environment, the addition of the following risk reduction measures and label requirements are proposed:

In addition to these risk reduction measures, labels will be updated to meet current standards.

To reach its decision, Health Canada conducted scientific evaluations to determine the potential impact of S-metolachlor in Canada. This included reviewing any new and applicable information related to conditions for use, toxicology, occupational and residential exposure, dietary exposure, value, and impact on the environment. Results from these evaluations show that with the implementation of updated risk reduction measures, S-metolachlor continues to meet Health Canada's requirements for the protection of the environment.

How to get involved

This consultation comment period is open from 29 February 2024 and closing on 29 May 2024 (90 calendar days inclusively).

To comment on PRVD2024-01:

Please be sure to include the title of the consultation document on which you are commenting.

Health Canada will consider all comments received by the end of the consultation comment period (by 29 May 2024) before making a final decision on the proposed re-evaluation decision for S-metolachlor.

View a summary of the proposed decision

If you would like to request additional information on the supporting scientific documents for this proposed special review decision, contact the Pest Management Information Service. Include the following information in the request:

Related information

Reporting to the people of Canada

Health Canada will make the results of this consultation available on this website. Once the decision on S-metolachlor and R-enantiomer is finalized, the PMRA will post a re-evaluation decision document, which will include the decision, the reasons for it, a summary of the comments received on the proposed decision, and Health Canada's response to these comments, on the Pesticides and Pest Management Reports and Publications portion of

If you have any questions, contact the Pest Management Information Service.

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