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Canada - Final Regulatory Action
Phorate CAS number:
Date circular:

Chemical name: Phosphorodithioic acid, O,O-diethyl S-[(ethylthio)methyl] ester

Final regulatory action has been taken for the category: Pesticide

Final regulatory action: The chemical is Severely Restricted

Use or uses prohibited by the final regulatory action:

All formulation of phorate and all uses were phased-out as 2004, with the exception of use on potatoes.

Pesticide use or uses that remain allowed:

Registration of Thimet 15G Soil & Systemic Insecticide Granular on potatoes continues for the short term

The final regulatory action was based on a risk or hazard evaluation: Yes

Summary of the final regulatory action:

The use of phorate and associated end-use products (EP) entails an unacceptable risk of harm to the agricultural worker pursuant to Section 20 of the Canadian Pest Control Product (PCP) Regulations. As a result, the Pest Management Regulatory Agency (PMRA) has determined that all uses of phorate are to be phased out as outline below.
Uses of phorate and associated end-use products on corn, lettuce, beans and rutabagas were phased-out as end of December 2004.
Due to the lack of alternatives to phorate for control of wireworm on potatoes, the registration of phorate, for this uses only, will be continued for the short term, with interim mitigation to protect workers (engineering controls, requirements regarding additional Personal Protective Equipment (PPE) and the environment (environmental statements on the label). Please refer to the RRD 2004-11, Appendix II for proposed engineering controls, PPE and other proposed label statements.

The reasons for the final regulatory action were relevant to: Environment

Summary of known hazards and risks to the environment:

The PMRA currently conducts a deterministic assessment of the environmental risk of pest control products. Environmental risk is characterized using the quotient method, which uses the ratio of the estimated environmental concentrations to the effects end point of concern. Quotient values less than one are considered indicative of a low hazard to non-target organisms, whereas values greater than one are considered to indicate that some degree of hazard exists for effects on non-target organisms.
Phorate is highly toxic to all terrestrial and aquatic species tested. Incident reports of bird and mammal fatalities in Canada, the U.S, and the U.K support the conclusion that phorate presents a significant risk to birds and wildlife. One granule is sufficient to kill a mall bird or mammal.
Surface broadcast application presents the greatest risk owing to the large number of exposed granules. Although soil incorporation is expected to lower the risk of terrestrial and aquatic exposure, it still presents a very high risk owing to unincorporated granules remaining exposed of the surface. The risk to small and moderate sized birds and small or moderately sized mammals remains high to very high with either method of application. Owing to its extreme toxicity to all organisms tested, the very high risk to moderate and smaller sized birds and mammals, the incident reports of bird an mammal mortalities (including large raptors in Canada), plus the persistence and mobility of the toxic sulfoxide and sulfone transformation products, the PMRA has concluded that the use of phorate in Canada presents a high risk to the environment.

Expected effect of the final regulatory action in relation to the environment:

Reducing the risk of environmental exposure to phorate in a manner that is the least disruptive to the need to protect agricultural crops from pests.

Date of entry into force of the final regulatory action: 31/12/2004

No further use was allowed after December 2004, except on potatoes