Re-evaluation Note REV2011-05, Re-evaluation of Pyrethroids, Pyrethrins and Related Active Ingredients

Pest Management Regulatory Agency
20 December 2011
ISSN: 1925-0649 (PDF version)
Catalogue number: H113-5/2011-5E-PDF (PDF version)

The purpose of this document is to notify registrants, pesticide regulatory officials and the Canadian public of Health Canada's Pest Management Regulatory Agency's (PMRA) approach for the re-evaluation of the pyrethroids, pyrethrins and related synergists.

PMRA is re-evaluating older active ingredients and their uses to determine their continued acceptability in light of current regulatory standards. Under section 16 of the  Pest Control Products Act, re-evaluations are initiated on a cyclical basis for pest control products whose active ingredient was first registered after 1 April 1995. The PMRA's proposed approach for this new program is described in Re-evaluation Note REV2010-18, Re-evaluation Program.

Ten of the active ingredients that are pyrethroids, pyrethrins or synergists were registered in Canada before 1995, and re-evaluations for these have already been initiated. Several other active ingredients in this group were registered in or after 1995 and would become subject to re-evaluation in the near future.

In order to allow for a consistent approach to the risk assessment and risk management for these active ingredients, the PMRA will proceed with the re-evaluations of these actives as a "pyrethroid cluster". The PMRA will aim to complete proposed re-evaluation decision documents for each of the individual active ingredients by 2016. Table 1 presents the active ingredients that will be re-evaluated in this cluster.

Registrants of technical grade products for each of these active ingredients have been notified directly of the data required in order for the PMRA to proceed with the risk assessments, as reported in the section 19 notices (available through the Pesticides and Pest Management section of Health Canada's website, Registrants of associated end-use products should also be prepared to contribute to the supporting data package, by providing relevant data such as non-dietary exposure. These registrants may wish to cooperate in the preparation of requested data packages and should also indicate clearly if their company will be represented by a task force with respect to any of the data submitted.

The outcome of the individual re-evaluations will be reported in future published documents.

Table 1 - Pyrethroids, Pyrethrins and Synergists to be Re-evaluated as a Cluster
Chemical Name (on PMRA record) CAS No.
Allethrin isomers
(d-cis, trans allethrin and d-trans allethrin)
Piperonyl Butoxide (synergist) 51-03-6
Cyfluthrin* 68359-37-5
Cypermethrin 52315-07-8
Deltamethrin 52918-63-5
D-Phenothrin (sumithrin)* N/A
Lambda-cyhalothrin* 91465-08-6
Octylbicyclo Heptene Dicarboximide (synergist) 113-48-4
Permethrin 52645-53-1
Pyrethrins 8003-34-7
Resmethrin 10453-86-8
Tetramethrin 7696-12-0

* active ingredients first registered after 1995

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