Re-evaluation Note REV2013-09, Re-evaluation Project Plan for Clethodim

Pest Management Regulatory Agency
19 November 2013
ISSN: 1925-0649 (PDF version)
Catalogue number: H113-5/2013-9E-PDF (PDF version)

In Canada, clethodim is under re-evaluation by Health Canada's Pest Management Regulatory Agency (PMRA). The PMRA's pesticide re-evaluation program considers potential risks as well as the value of pesticide products to ensure they continue to meet standards of modern science and current policy established to protect human health and the environment. Under the authority of Section 16 of the  Pest Control Products Act, the registrants of clethodim were notified of the initiation of the re-evaluation of clethodim. Following this, the registrants of clethodim technical grade active ingredient in Canada indicated their intention to support all uses included on the labels of commercial class products in Canada. This Re-evaluation Note outlines a project plan and timeline for review, as well as summarizes the anticipated areas of focus related to the re-evaluation of clethodim.

Clethodim is a systemic, postemergence herbicide that has been registered in Canada since 1992. Clethodim is currently registered for the control of a number of grasses and weeds on various terrestrial feed and food crops (Use-Site Categories 13 and 14), and for industrial oil seed and fibre crops (Use-Site Category 7). Registered clethodim end-use products are formulated as emulsifiable concentrates, to be applied by ground or aerial equipment.

The project plan discussed below outlines the anticipated areas of focus and risk assessments required to complete the re-evaluation of clethodim, as well as additional data required. Should additional information become available during the re-evaluation period that affects the regulatory status of clethodim, the PMRA will reconsider the areas of focus and risk assessments required. Currently, a proposed re-evaluation decision for clethodim is anticipated to be published in 2014.

Re-evaluation Project Plan

Human Health Risk Assessment

Comprehensive human health risk assessments will be conducted for the re-evaluation of clethodim. These assessments will cover toxicology, dietary, worker applicator and postapplication exposures, as well as non-occupational assessments for aggregate, residential and bystander exposures.

Environmental Risk Assessment

A comprehensive environmental risk assessment will be conducted for the re-evaluation of clethodim.

Environmental risk mitigation measures will also be reviewed to ensure consistency with
current label requirements and the Toxic Substances Management Policy will be


The value of clethodim will be considered. The viability of alternatives will be examined if risks of concern are identified.

Data Requirements

Additional data requirements related to toxicology have been identified for clethodim and were requested from the technical registrants. For details, see Appendix I.

Anticipated Timeline for Re-evaluation

A proposed re-evaluation decision for clethodim is anticipated to be published for consultation in 2014.

Additional Information

PMRA documents can be found in the Pesticides and Pest Management section of Health Canada's website at PMRA documents are also available through the Pest Management Information Service. Phone: 1-800-267-6315 within Canada or 1-613-736-3799 outside Canada (long distance charges apply); fax: 613-736-3798; e-mail:

Appendix I - Data Requirements for the Re-evaluation of Clethodim


DACO 4.5.13 — Subchronic Neurotoxicity Study
DACO 4.8 — Other (Immunotoxicity Study)

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