Re-evaluation Decision RVD2023-07, Piperonyl Butoxide and Its Associated End-use Products

Pest Management Regulatory Agency
2 March 2023
ISSN: 1925-1025 (PDF version)
Catalogue number: H113-28/2023-7E-PDF (PDF version)

Summary

Table of contents

• Re-evaluation decision for piperonyl butoxide and associated end-use products
• Re-evaluation decision for piperonyl butoxide
• Risk mitigation measures
• Implementation of the re-evaluation decision
• Health considerations
• Environmental considerations
• Next steps
• Other information
• Appendix I Registered products containing piperonyl butoxide in Canada

Re-evaluation decision for piperonyl butoxide and 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), on behalf of the Minister of Health, to ensure that they continue to have acceptable risk to human health and the environment and have acceptable value. The re-evaluation considers available data and information^{Footnote 1} from pesticide registrants, published scientific reports, existing assessments, other governments, and international regulatory authorities, as well as comments received during public consultations. Health Canada applies internationally accepted current risk assessment methods as well as risk management approaches and policies. More details, on the legislative framework, risk assessment and risk management approach, are provided under Evaluation Approach of the full version of Re-evaluation Decision RVD2023-07, Piperonyl Butoxide and Its Associated End-use Products.

Piperonyl butoxide is a synergist that is always co-formulated with a pesticide (mainly pyrethrins and synthetic pyrethroids) to enhance the effectiveness of the co-formulated active ingredients. Products containing piperonyl butoxide are used to control a broad spectrum of insect pests on a wide variety of sites, including commercial and domestic agricultural and structural uses, and fish in bodies of water. Piperonyl butoxide is a component of the integrated pest management of common household pests, such as bed bugs, cockroaches, fleas, and indoor ants. Products containing piperonyl butoxide are available in various formulations including dusts, pressurized products, pastes, solutions, and emulsifiable concentrates. Currently registered products containing piperonyl butoxide can be found in the Pesticide Product Information Database and in Appendix I.

The Proposed Re-evaluation Decision PRVD2020-09, Piperonyl Butoxide and Its Associated end-use Products^{Footnote 2} containing the evaluation of piperonyl butoxide and proposed decision was published 17 September 2020 for a 90-day consultation period. An additional 75 days for consultation was provided in response to requests from stakeholders to accommodate time constraints imposed by pandemic measures; the consultation period ended on 1 March 2021.

A request for data under section 19 of the Pest Control Products Act to confirm that application rates and use directions on product labels were consistent with the rates used in the health risk assessments was also issued on the day of publication of PRVD2020-09. The deadline for the required data was also extended to 1 March 2021 due to requests from registrants and stakeholders. The data were used to inform a revised use pattern analysis, which confirmed use sites, crops, formulations, application equipment, rates, container sizes, active ingredient concentration, number of applications and application intervals. The revised use pattern is considered for the updated science evaluations for human health and the environment.

PRVD2020-09 proposed continued registration for most uses provided the additional risk mitigation measures are in place. The proposed risk mitigation measures included increased personal protective equipment (PPE); limit on the amount of active ingredient handled per day for commercial-class products; 2-hour re-entry interval after indoor residential applications; precautionary statements to protect pollinators and the environment; and spray buffer zones. The proposed uses for cancellation for commercial products included uses on pastures, direct application to stored grain and seeds, direct application to ponds, lakes, reservoirs, and streams; spot-on application to poultry; space spray application while livestock, other than poultry, are present; and broadcast application for bed bug control on commercial-class dust and pressurized product labels. The proposed uses for cancellation for domestic products included all garden and greenhouse food uses; all pressurized products used as total release foggers; indoor uses on domestic-class product labels; indoor space spray uses (not including metered release) on pressurized product labels; and all claims related to killing lice on non-host sites.

Health Canada received comments and information relating to the health and value assessments during the public consultation period conducted in accordance with section 28 of the Pest Control Products Act. Commenters are listed in Appendix II of RVD2023-07. These comments are summarized in Appendix III of RVD2023-07 along with the responses by Health Canada. These comments and new data/information resulted in revisions to the occupational and non-occupational exposure assessments, aggregate exposure risk assessment, and environmental risk assessment (see Science Evaluation Update of RVD2023-07) and resulted in changes to the proposed re-evaluation decision as described in PRVD2020-09.

A reference list of information used as the basis for the proposed re-evaluation decision is included in PRVD2020-09, and further information used in the re-evaluation decision is listed in Appendix VII of RVD2023-07. Therefore, the complete reference list of all information used in this final re-evaluation decision includes both the information set out in PRVD2020-09 and the information set out in Appendix VII of RVD2023-07.

This summary presents the final re-evaluation decision^{Footnote 3} for the re-evaluation of piperonyl butoxide, including the required amendments (risk mitigation measures) to protect human health and the environment, as well as label amendments required to bring labels to current standards. All products containing piperonyl butoxide that are registered in Canada are subject to this re-evaluation decision.

Re-evaluation decision for piperonyl butoxide

Health Canada has completed the re-evaluation of piperonyl butoxide. Under the authority of the Pest Control Products Act, Health Canada has determined that continued registration of many uses of piperonyl butoxide is acceptable. An evaluation of available scientific information found that some uses of piperonyl butoxide products meet current standards for protection of human health and the environment and have acceptable value when used according to revised conditions of registration, which includes new mitigation measures.

The following uses of piperonyl butoxide are cancelled since health risks or value were not shown to be acceptable when used according to the current conditions of registration, or when additional mitigation is considered:

• Domestic-class pressurized products used as total release foggers (including lock-valve mechanisms)
• Domestic-class pressurized products used in metered-release devices
• Space spray uses on domestic-class liquid product labels
• Domestic handler applications using handheld or stationary fogging/misting equipment on liquid domestic-class products
• Uses on pastures; direct application to bulk or bagged stored grain; direct application to ponds, lakes, reservoirs, and streams; space spray application while livestock, other than poultry, are present; and garden and greenhouse food uses on domestic-class labels
• Claims related to killing lice on mattresses, bedding, furniture, and garments.

Label amendments, as summarized below and listed in Appendix IV of RVD2023-07, are required.

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 required amendments, including any revised/updated label statements and/or mitigation measures, as a result of the re-evaluation of piperonyl butoxide, are summarized below. Refer to Appendix IV of RVD2023-07 for details.

Human health - Risk mitigation:

To protect consumers, bystanders or workers the following uses are cancelled:

• All domestic-class pressurized products used as total release foggers (including lock-valve mechanisms).
• All domestic-class pressurized products used in metered-release devices.
• Space spray uses on domestic-class liquid product labels.
• Domestic handler applications using handheld or stationary fogging/misting equipment on liquid domestic-class products

Data were not available to support certain uses that could result in dietary exposure; therefore, the following risk-reduction measures are required:

• Cancellation of: uses on pastures; direct application to bulk or bagged stored grain; direct application to ponds, lakes, reservoirs, and streams; space spray application while livestock, other than poultry, are present; and garden and greenhouse food uses on domestic-class product labels.
• Limit the application rate of space spray applications while poultry are present.
• Dust application is to be limited to areas that do not affect food, feed, or livestock used to produce food commodities (for example, voids, non-food areas).

To minimize dietary risk to Canadians, the following risk reduction measures are required:

• Revocation of the maximum residue limit (MRL) of 20 ppm on raw cereals, to reduce dietary exposure from residues in cereal grains.
• The number of applications for all outdoor uses (for example: campgrounds, roadsides, and grassy areas) are to be reduced such that the yearly cumulative rate is less than 1100 g a.i./ha, to reduce dietary exposure from residues in drinking water.
• Structural labels are to be updated as per the 2020 PMRA Guidance Document, Structural Pest Control Products: Label Update, to reduce dietary exposure from residues in food or feed after a location is treated with a structural product.

To protect consumers, and bystanders (including children) who may be using the product or entering treated sites, the following risk reduction measures are required:

• For surface spray applications, label directions must be added or revised to specify the pests controlled, the application rate and application type (for example, perimeter/spot, crack and crevice) that were shown to have acceptable risk in the human health risk assessment (Appendix IV, Tables 1 and 3). This includes label statements that clearly define and establish the conditions of use for residential areas where children may be present versus non-residential areas where children are not expected to be present.
• Limit the application rate for commercial-class products used as a broadcast surface spray and mosquito abatement, and in metered release devices.
• A 2-hour re-entry interval for commercial-class products applied as an indoor space spray (liquid and pressurized products, excluding metered release products). The commercial applicator is responsible for notifying the occupants and others of the re-entry period requirement.
• Limit the application rate for domestic-class pressurized products used as an indoor space spray.
• A label statement prohibiting use of handheld and stationary fogging/misting equipment on liquid domestic-class labels.
• A label statement prohibiting use of domestic-class greenhouse end-use products in commercial greenhouses.
• Additional label statements for domestic and commercial-class products used as structural pest control products as per the 2020 PMRA Guidance Document, Structural Pest Control Products: Label Updates.

To protect workers using commercial-class products or entering treated sites following application of commercial-class products, the following risk reduction measures are required:

• Increased personal protective equipment (PPE).
• Limit the amount of product handled per day.
• Restricted-entry intervals (REIs) for outdoor ornamentals.
• Re-entry intervals for all other sites.

To protect pets treated with sprays or shampoos containing piperonyl butoxide, the following risk reduction measures are required:

• Label statements to inform consumers of the possible side effects that may be expected in their pets following use.
• Label statements to prohibit the use of other companion animal products with the same active ingredient(s).

Environment - Risk mitigation:

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

• Standard environmental hazard statements to inform uses of the potential toxic effects on bees, beneficial arthropods, and aquatic organisms.
• Precautionary statements and additional application instructions on product labels with foliar applications (commercial and domestic) to prevent terrestrial plant damage/death.

Value

• Cancellation of label claims related to killing lice on mattresses, bedding, furniture, and garments.

Health - Label improvements to meet current standards:

• Label statements for domestic- and commercial-class products used as structural pest control products are required to be updated as per the 2020 PMRA Guidance Document, Structural Pest Control Products: Label Updates.
• Label statements for domestic-class products used on companion animals are required to be updated as per DIR2002-01, Canadian Label Improvements for Pesticides used on Companion Animals.

Implementation of the re-evaluation decision

Regulatory Directive DIR2018-01, Policy on Cancellations and Amendments Following Re-evaluation and Special Review provides general timelines for implementation of post-market decisions.

When a re-evaluation or special review decision requires cancellation of pest control products, consistent with Health Canada's Information Note: update on implementation of post-market decisions (2021),Health Canada will immediately cancel pest control product registrations on the date of a decision made under paragraph 21(2)(b) of the Pest Control Products Act.

If there are no serious and imminent risks to human health or the environment, Health Canada will allow for a phase-out period consistent with the Cancellation Policy and will impose any conditions necessary for carrying out the purposes of the Pest Control Products Act under the authority of paragraph 21(5)(a) of the Pest Control Products Act.

Health considerations

Risks to human health from exposure to a pesticide are estimated by comparing potential exposures with the most relevant endpoint from toxicology studies, with standard protection factors incorporated to further protect human health, including the most sensitive population. These factors provide an inherent level of protection from exposures that could result in adverse effects to human health. Furthermore, Health Canada applies additional protection factors if warranted by the hazard profile of the pesticide or by the quality and completeness of the underlying data. When risks of concern are identified in the human health exposure scenarios, it does not necessarily mean that exposure will result in adverse effects, but mitigation measures to reduce potential risks would be required.

For piperonyl butoxide products co-formulated with pyrethrins/synthetic pyrethroids, 234 human incident reports involving 48 products were received between 2007 and 2022 and were considered to be possibly related to the reported product when used according to the label. For the majority of human health incidents, reported symptoms included respiratory effects (such as cough, nasal congestion, and respiratory irritation), skin or eye irritation, tingling mouth or skin, nausea, dizziness, or headache. These effects were associated mostly with domestic-class products used in indoor sites, and were mainly minor in severity, were of short duration and resolved quickly without medical treatment. For these domestic-class indoor products associated with human incidents, as well as registered domestic products with similar formulations and use pattern, the required label amendments must be implemented no later than 18 months after the publication date of this re-evaluation decision (Appendix I, Table 1). For domestic-class indoor products that have been cancelled (Appendix I, Table 2), product cancellations are in effect as of the date of this decision document with an 18-month phase-out period. During this 18-month phase-out period, continued possession, handling, storage, and use of existing stock in Canada at the time of cancellation of these products (Appendix I, Table 2) will be authorized under paragraph 21(5)(a) of the Pest Control Products Act.

For the products requiring amendments listed in Appendix I, Table 3, label amendments must be implemented no later than 24 months after the publication date of this re-evaluation decision.^{Footnote 4} Products listed in Appendix I, Table 4 are cancelled as of the date of this decision with a 3-year phase- out period authorized under paragraph 21(5)(a) of the Pest Control Products Act. During this 3-year phase-out period, continued possession, handling, storage, and use of existing stock in Canada at the time of cancellation of these products (Appendix I, Table 4) will be authorized under paragraph 21(5)(a) of the Pest Control Products Act.

In addition, for the products subject to cancellation in Appendix I, Table 4 there are no serious and imminent risks identified or expected during the phase-out period.

This approach prioritizes the implementation of mitigation measures for products associated with human incident reports as well as the cancellation of products that are similar in use. This will facilitate the practical and orderly implementation of mitigation measures through label amendments and cancellations.

Potential and relative health risks for products containing piperonyl butoxide are acceptable during these implementation periods for label amendments.

Environmental considerations

To comply with this decision, the required amendments (mitigation measures and label updates) to protect the environment must be implemented on product labels no later than 24 months after the publication date of this re-evaluation decision. The risks identified are considered acceptable because they are not expected to cause irreversible harm over the label implementation period. Potential effects of piperonyl butoxide include a localized reduction in aquatic organism and pollinator abundance. Affected populations have the potential to recover following implementation of the additional restrictions, which will reduce overall exposure. Recovery is expected because risks to these non-target organisms are geographically limited to areas where these piperonyl butoxide products are applied and areas adjacent to application sites. The presence of unaffected non-target organisms in areas where piperonyl butoxide products are not being used will further facilitate recovery since unaffected organisms can move back into areas where effects may have occurred. Overall, the risk to these organisms is acceptable over the period required to implement the mitigation measures.

For the restricted class product subject to cancellation there are no serious and imminent risks identified or expected. The product label indicates the product is toxic to aquatic organisms and can only be used following consultation and permitting from Provincial and Federal Fish and Wildlife Agencies. As such, use is monitored, and environmental impacts are considered during the permit application process. Therefore a 3-year phase out period for this cancelled product is acceptable.

Next steps

To comply with this decision, the required pest control product amendments and cancellations must be made within the timelines described in this section. This decision is applicable to all products containing piperonyl butoxide, see Appendix I for details.

Amendments to product registrations

1. For pest control products listed in Appendix I, Table 1: The required amendments (risk mitigation measures and label updates) to domestic-class products with indoor uses identified in Appendix I, Table 1 must be implemented no later than 18-months after the final decision publication. Accordingly, both registrants and retailers will have up to 18-months from the date of this decision document to transition to selling the product with the newly amended labels. Similarly, users will also have the same 18-month period from the date of this decision document to transition to using the newly amended labels, which will be available on the Public Registry.
2. For pest control products listed in Appendix I, Table 3: Any remaining products, not described above, requiring label amendments (risk mitigation measures and label updates) (Appendix I, Table 3) must be implemented no later than 24 months after the publication date of this decision document. Accordingly, both registrants and retailers will have up to 24 months from the date of this decision document to transition to selling the product with the newly amended labels. Similarly, users will also have the same 24-month period from the date of this decision document to transition to using the newly amended labels, which will be available on the Public Registry.

Cancellation of product registrations

1. For pest control products listed in Appendix I, Table 2: As of the date of this decision document, some domestic-class products with indoor uses are cancelled pursuant to paragraph 20(1)(b) of the Pest Control Products Act (Appendix I, Table 2). An 18-month phase-out period is established to deplete existing stocks in Canada.

During this phase-out period, continued possession, handling, storage, and use of existing stock in Canada of these products will be authorized under paragraph 21(5)(a) of the Pest Control Products Act as per the schedule below:

• Authorized for sale (of existing stocks in Canada) by registrant six (6) months from the date of decision, followed by;
• Authorized for sale by retailer/distributor (if applicable) six (6) months from the last date of sale by registrant, followed by; and
• Authorized for use six (6) months from the last date of sale by retailer/distributor.

2. For pest control products listed in Appendix I, Table 4: As of the date of this decision document, some products, not described above, are cancelled pursuant to paragraph 20(1)(b) of the Pest Control Products Act (Appendix I, Table 4) with a 3-year phase-out period to deplete existing stocks in Canada.

During this period, continued possession, handling, storage, and use of existing stock in Canada of these products will be authorized under paragraph 21(5)(a) of the Pest Control Products Act as per the schedule below:

• Authorized for sale (of existing stocks in Canada) by registrant one (1) year from the date of decision, followed by;
• Authorized for sale by retailer/distributor (if applicable) one (1) year from the last date of sale by registrant, followed by; and
• Authorized for use one (1) year from the last date of sale by retailer/distributor.

Products that have a phase-out period will be listed as "Phase-out" in the Public Registry for the duration of their authorization. During the phase-out period, importing or manufacturing of cancelled pest control products containing piperonyl butoxide in Canada is prohibited (Appendix I, Tables 2 and 4).

In addition, registrants are required to continue to comply with sales and incident reporting obligations (relating to all pest control products containing piperonyl butoxide) during the phase-out period for the pest control products in Appendix I, Tables 2 and 4.

Other information

Any person may file a notice of objection^{Footnote 5} regarding this decision on piperonyl butoxide and its associated end-use products within 60 days from the date of publication of RVD2023-07. For more information regarding the basis for objecting (which must be based on scientific grounds), please refer to the Pesticides section of the Canada.ca website (Request a Reconsideration of Decision) or contact PMRA's Pest Management Information Service.

The relevant confidential test data on which the decision is based (as referenced in PRVD2020-09 and in Appendix VII of RVD2023-07) are available for public inspection, upon application, in the PMRA's Reading Room. For more information, please contact PMRA's Pest Management Information Service.

Appendix I Registered products containing piperonyl butoxide in Canada