Proposed Re-evaluation Decision PRVD2022-18, Predacide Uses of Strychnine and Sodium Monofluoroacetate and their Associated End-use Products

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Pest Management Regulatory Agency
31 August 2022
ISSN: 1925-0967 (PDF version)
Catalogue number: H113-27/2022-18E-PDF (PDF version)

Table of contents

• Proposed re-evaluation decision for the predacide uses of strychnine and sodium monofluoroacetate and their associated end-use products
• Proposed re-evaluation decision for the predacide uses of strychnine and sodium monofluoroacetate
• Risk mitigation measures
• International context
• Next steps
• Other information
• Additional scientific information

Proposed re-evaluation decision for the predacide uses of strychnine and sodium monofluoroacetate and their associated end-use products

Under the authority of the Pest Control Products Act, all registered pesticides must be re-evaluated by Health Canada's Pest Management Regulatory Agency (PMRA) to ensure that they continue to meet current health and environmental standards and continue to have value. The re-evaluation considers data and information from pesticide manufacturers, published scientific reports and other regulatory agencies. Health Canada applies internationally accepted risk assessment methods as well as current risk management approaches and policies.

Strychnine is a toxicant registered as a restricted class end-use product used to kill predators and skunks in Alberta. It is applied as tablets in meat baits (for example, pieces of animal meat or fish or animal carcasses) to kill wolves, coyotes or bears in order to prevent predation of wildlife populations (for example, woodland caribou populations) threatened with extirpation or those wildlife populations that are economically or ecologically important and to prevent human-predator conflicts (i.e., predation of domestic animals such as livestock and attacks on humans). Only authorized employees of Alberta Environment and Parks, Fish and Wildlife Division are permitted to sell, store, handle or use the tablet product. Strychnine is also applied as a solution injected into eggs used as baits to kill skunks in rabies control programs. This solution product is restricted for storage, handling and use to employees of Alberta Agriculture and Food or municipal employees, authorized under the Alberta Agricultural Pests Act, provided that such designated or authorized persons are trained and certified.

Sodium monofluoroacetate (also known as Compound 1080) is a toxicant registered as a restricted class end-use product used to kill coyotes and wolves in Alberta. It is used to either protect domestic animals (for example, livestock) or wildlife species at risk from predation, when there is a threat to human safety and/or other problems posed by these predators. Sodium monofluoroacetate is applied as a solution in neck collars worn by livestock prey (i.e., goat or sheep) or as tablets in meat baits (for example, chicken heads or animal carcasses). Only persons authorized under the Alberta Agricultural Pests Act and by designated Fish and Wildlife Officers of the Government of Alberta are permitted to store, handle or use these products.

Currently registered products containing strychnine or sodium monofluoroacetate used as predacides can be found in the Pesticide Product Information Database and in Appendix I of the full version of Proposed Re-evaluation Decision PRVD2022-18, Predacide Uses of Strychnine and Sodium Monofluoroacetate and their Associated End-use Products. Appendix II of PRVD2022-18 lists all uses for which strychnine or sodium monofluoroacetate is presently registered.

This document (PRVD2022-18) presents the proposed re-evaluation decision for the predacide uses of strychnine and sodium monofluoroacetate, including the proposed amendments (risk mitigation measures) to protect human health and the environment, as well as the science evaluation on which the proposed decision is based. All products containing strychnine and sodium monofluoroacetate that are registered in Canada as predacides are subject to this proposed re-evaluation decision. This document is subject to a 90-day public consultation period,^{Footnote 1} during which the public (including the pesticide manufacturers and stakeholders) may submit written comments and additional information to PMRA Publications. The final re-evaluation decision will be published after taking into consideration the comments and information received during the consultation period.

Proposed re-evaluation decision for the predacide uses of strychnine and sodium monofluoroacetate

Under the authority of the Pest Control Products Act and based on an evaluation of available scientific information, Health Canada is proposing continued registration of the predacide uses of strychnine and sodium monofluoroacetate and their associated end-use products registered for sale and use in Canada.

With respect to human health, occupational risks were shown to be acceptable when strychnine and sodium monofluoroacetate are used according to the conditions of registration, which includes proposed new mitigation measures, such as revised disposal statements and revisions to personal protective equipment (PPE) requirements for all products. As there are no feed or food uses for strychnine and sodium monofluoroacetate, no dietary exposure through food or drinking water is expected. As such, the dietary and aggregate risks from the currently registered uses are acceptable.

The environmental risk assessment found that there is a risk of death to individual non-target animals who are exposed to strychnine or sodium monofluoroacetate; however, population level effects are not expected given the limited use of these products. The risks to the environment were shown to be acceptable at the population level when strychnine and sodium monofluoroacetate are used according to the conditions of registration, which includes proposed new mitigation measures, such as improved label use directions, updated reporting requirements and a requirement for a registrant-implemented product stewardship program.

Strychnine has value to kill predators in the government of Alberta's wildlife protection programs to protect species at risk of extirpation, such as the woodland caribou. It is also of value for livestock protection or where predators pose a risk to humans when alternative control strategies are not viable or effective. Lastly, it also has value to kill skunks in the government of Alberta's rabies management program, a serious reportable disease impacting all mammals including people.

Sodium monofluoroacetate collars target specific individual wolves and coyotes preying on small livestock. They have value when alternative methods (both non-lethal and lethal) in a herd management program are insufficient or impractical to protect livestock. Sodium monofluoroacetate tablets have value to kill wolves and coyotes where predation has occurred on livestock or where they pose a risk to humans. They are also of value for use in areas to protect prey animals from extirpation.

Risk mitigation measures

Registered pesticide product labels include specific directions for use. Directions include risk mitigation measures to protect human health and the environment and must be followed by law. The proposed label amendments including any revised/updated label statements and/or mitigation measures, as a result of the re-evaluation of the predacide uses of strychnine and sodium monofluoroacetate, are summarized below. Refer to Appendix III of PRVD2022-18 for details.

Product stewardship program - outline of minimum requirements

A registrant-implemented product stewardship program is proposed for all products. The goal of this program is to ensure the proper handling and use of restricted-class products containing strychnine or sodium monofluoroacetate.

Registrants are required to:

• Develop and implement training programs for the use of these products that (1) emphasize the requirement to follow the label directions, and (2) educate users that predacides are to be used in an Integrated Pest Management (IPM) program and only when other management methods have been attempted and deemed not feasible or effective.
• Keep, monitor and maintain records (in electronic format) relating to the use of predacides ("Toxicant Use Record") which must be available upon request at any time for Health Canada review.
  • Users will be required to submit completed copies of the "Toxicant Use Record" for each use of a predacide to registrants.
• Notify Health Canada within 24 hours when any use record indicates use not in accordance with labelled directions. Cease the use of the predacide until Health Canada reviews and provides direction.

Human health - Risk mitigation:

To protect workers from occupational exposure, the following risk-reduction measures are proposed for strychnine and sodium monofluoroacetate:

• Update personal protective equipment statements for all restricted class products to current standards and to specify that the PPE must be worn when handling the product or treated baits.
• Revised disposal statements are proposed for all products containing strychnine or sodium monofluoroacetate to require incineration for the disposal of product, treated bait, or carcasses.

Environment - Risk mitigation:

To protect the environment, the following risk-reduction measures are proposed:

Strychnine Wolf, Coyote and Black Bear Control Predacide (Reg. No. 20410)

• To further minimize risk to non-target species, the following are proposed:
  • Updated and clarified reporting requirements.
  • A statement prohibiting the use of drop baits in conjunction with poisoned carcasses.
  • Requirement for an additional site visit after snow melt to ensure sites are properly cleaned/closed.

Strychnine Predacide Skunk Control (Reg. No. 24510)

• Proposed requirement for the use of a bait station with poisoned eggs to reduce risk to non-target species (for example, dogs, coyotes, wolves, bears, cougars).
• To further minimize risk to non-target species, the following are proposed:
  • A statement indicating that this product is only to be used as a last resort in management programs after other management methods have been attempted and deemed not feasible or effective.
  • Updated and clarified reporting requirements.
  • Requirement to retrieve and dispose of poisoned carcasses and to inspect areas around bait stations for poisoned carcasses at least every seven days rather than the current requirement of every 15 days.
  • A statement prohibiting the use of this product in areas where species at risk may consume the poisoned eggs.

Sodium Monofluoroacetate Predacide (Reg. No. 18300)

• To further minimize risk to non-target species, the following are proposed:
• Updated and clarified reporting requirements.
• A statement prohibiting the use of drop baits in conjunction with poisoned carcasses.
• Label improvements to harmonize the use limitations for the target animals (coyote and wolf).
• Removal of the option to cover baits with vegetation or other material, which may be displaced by wind leaving baits exposed, to prevent access to birds.

Sodium Monofluoroacetate Toxic Collar Solution (Reg. No. 24512)

• To further minimize risk to non-target species, the following are proposed:
• Updated and clarified reporting requirements.
• Collar monitoring requirement to be updated from 48 hours to every 24 hours.
• Requirement to remove the collar if no predation has occurred within 30 days.
• Requirement to immediately report missing collars to Alberta Agriculture, Forestry and Rural Economic Development.
• Requirement to dispose of poisoned carcasses (collared livestock and target/non-target organisms) in accordance with labelled disposal requirements.

Value

Label improvements are proposed to clarify label use directions for strychnine and sodium monofluoroacetate products:

• Amendments to vague site claims (for example, change "domestic animal" to "livestock", claims, refinement of "wildlife populations that are economically or ecologically important");
• Change the claim of "control" to "reduces" or "kill" as the goals are different in these programs; (i.e., reduction in predator population in a localized area or targeting individual animals);
• Additional IPM statements related to the use of non-lethal and lethal strategies with these products being intended as a last resort in management programs as indicated in the Product Stewardship Program; and
• For the product used to kill skunks in rabies control programs, addition of the minimum requirements for bait stations (for example, tamper resistance, weather resistance, etc.).

International context

Strychnine is currently acceptable for use in other Organisation for Economic Co-operation and Development (OECD) member countries, including the United States and Australia. Internationally and within the available information, no evidence of a ban as of 29 June 2022 to prohibit all uses of strychnine for health or environmental reasons has been identified.

Sodium monofluoroacetate is currently acceptable for use in other Organisation for Economic Co-operation and Development (OECD) member countries, including the United States, Australia and New Zealand. Internationally and within the available information, no evidence of a ban as of 29 June 2022 to prohibit all uses of sodium monofluoroacetate for health or environmental reasons has been identified.

Next steps

Upon publication of this proposed re-evaluation decision, the public, including the registrants and stakeholders are encouraged to submit additional information that could be used to refine risk assessments during the 90-day public consultation period.

All comments received during the 90-day public consultation period will be taken into consideration in preparation of re-evaluation decision document,^{Footnote 2} which could result in revised risk mitigation measures. The re-evaluation decision document will include the final re-evaluation decision, the reasons for it and a summary of comments received on the proposed re-evaluation decision with Health Canada's responses.

Refer to Appendix I of PRVD2022-18 for details on specific products impacted by this proposed decision.

Other information

The relevant confidential test data on which the proposed decision is based (as indicated in the References Section of PRVD2022-18) are available for public inspection, upon application, in Health Canada's Reading Room. For more information, please contact Health Canada's Pest Management Information Service.

Additional scientific information

No additional scientific data are required at this time.