Proposed Registration Decision PRD2023

Pest Management Regulatory Agency 8 June 2023 ISSN: 1925-0886 (PDF version) Catalogue number: H113-9/2023-6E-PDF (PDF version)

This page is a summary of the consultation document. If you would like to comment, please request the full consultation document.

To obtain a full copy of Proposed Registration Decision PRD2023-06, Pentachlorophenol Treated Poles and Cross-Arms please contact our publications office.

Should you require further information please contact the Pest Management Information Service.

Pentachlorophenol was registered for industrial uses as a heavy duty wood preservative in Canada until 4 October 2022. Health Canada's Pest Management Regulatory Agency (PMRA) announced the cancellation of all pentachlorophenol products (one technical grade active ingredient and two commercial end-use products) on 4 October 2022. A one-year phase-out period was authorized under the Pest Control Products Act to allow wood treatment facilities to deplete existing stocks of these cancelled products. Details regarding the conditions of authorization and events leading up to the cancellation can be found in Re-evaluation Note REV2022-02, Update on the Special Review of Pentachlorophenol.

In general, articles that have been preserved with antimicrobials to protect them from microbial damage do not have to be registered under the Pest Control Products Act, as long as:

However, if the antimicrobial preservative is no longer registered or authorized under the Pest Control Products Act, the treated articles are no longer authorized. Since the authorization period of the pentachlorophenol products expires on 4 October 2023, the sale, import and installation of the treated wood would only be permitted to continue until the end of the phase-out period, 4 October 2023. Therefore, in order to continue use (i.e., installation) of already-treated utility poles and cross-arms in Canada beyond 4 October 2023, registration of the treated poles and cross-arms would be required.

Health Canada has reviewed an application to register Pentachlorophenol Treated Poles and Cross-Arms. Interested parties are encouraged to provide comments within 45 days of this publication.

Health Canada's Pest Management Regulatory Agency (PMRA), under the authority of the Pest Control Products Act, is proposing registration of Pentachlorophenol Treated Poles and Cross-Arms, for a finite period of three years (until 4 October 2026), for use in new line construction and replacement of damaged utility poles and/or cross-arms used in the transmission and distribution of electricity. These treated poles and cross-arms contain the active ingredient pentachlorophenol (plus related active chlorophenols) to prevent deterioration of the wood by wood-boring insects and fungi. This registration would allow for the continued possession, handling, transportation, storage, distribution, use (i.e., installation) and disposition of pentachlorophenol treated utility poles and cross-arms existing already in Canada as of 4 October 2023.

An evaluation of available scientific information found that, under the proposed conditions of use, the health and environmental risks and the value of the pest control products are acceptable.

This summary describes the key points of the evaluation, while the Science Evaluation of Proposed Registration Decision PRD2023-06, Pentachlorophenol Treated Poles and Cross-Arms provides detailed technical information on the human health, environmental and value assessments of Pentachlorophenol Treated Poles and Cross-Arms.

The key objective of the Pest Control Products Act is to prevent unacceptable risks to people and the environment from the use of pest control products. Health or environmental risk is considered acceptableFootnote 1 if there is reasonable certainty that no harm to human health, future generations or the environment will result from use or exposure to the product under its proposed conditions of registration. The Act also requires that products have valueFootnote 2 when used according to the label directions. Conditions of registration may include special precautionary measures on the product label to further reduce risk.

To reach its decisions, the PMRA applies modern, rigorous risk-assessment methods and policies. These methods consider the unique characteristics of sensitive subpopulations in humans (for example, children) as well as organisms in the environment. These methods and policies also consider the nature of the effects observed and the uncertainties when predicting the impact of pesticides. For more information on how the Health Canada regulates pesticides, the assessment process and risk-reduction programs, please visit the Pesticides section of the Canada.ca website.

Before making a final registration decision on Pentachlorophenol Treated Poles and Cross-Arms, Health Canada's PMRA will consider any comments received from the public in response to this consultation document.Footnote 3 Health Canada will then publish a Registration DecisionFootnote 4 on Pentachlorophenol Treated Poles and Cross-Arms, which will include the decision, the reasons for it, a summary of comments received on the proposed registration decision and Health Canada's response to these comments.

For more details on the information presented in this summary, please refer to the Science Evaluation of PRD2023-06.

Pentachlorophenol-treated utility poles and cross-arms are essential pieces of electrical grid infrastructure that have been treated with pentachlorophenol, an oil-borne heavy duty wood preservative. These utility poles and cross-arms are held in stock to maintain the grid's reliability through unpredictable weather events, to replace already installed poles and cross-arms at the end of their service life, and to advance new infrastructure projects.

Pentachlorophenol Treated Poles and Cross-Arms are unlikely to affect your health when used according to proposed label directions. Potential exposure to pentachlorophenol may occur to workers installing treated poles and cross-arms during the limited registration period. When assessing health risks, two key factors are considered:

The dose levels used to assess risks are selected to protect the most sensitive human population (for example, children and nursing mothers). As such, sex and gender are taken into account in the risk assessment. Only uses for which the exposure is well below levels that cause no effects in animal testing are considered acceptable for registration.

Toxicology studies in laboratory animals describe potential health effects from varying levels of exposure to a chemical and identify the dose level at which no effects are observed. The health effects noted in animals occur at dose levels more than 100-times higher (and often much higher) than levels to which humans are normally exposed when pesticide products are used according to label directions.

Pentachlorophenol treated poles and cross-arms are composed of various species of wood impregnated with pentachlorophenol. Due to the solid nature of the treated article and low concentration of pentachlorophenol in the final treated product, the treated poles and cross-arms are not expected to pose acute chemical hazards to human health, including acute toxic effects via the oral, dermal or inhalation routes, skin or eye irritation, or an allergic skin reaction.

International reviews and registrant-supplied short- and long-term (lifetime) animal toxicity tests, as well as information from the published scientific literature, were assessed for the potential of pentachlorophenol to cause neurotoxicity, immunotoxicity, chronic toxicity, cancer, reproductive and developmental toxicity, and various other effects. The most sensitive endpoints for risk assessment were effects on the liver and the developing fetus. There was some evidence to suggest that pentachlorophenol damaged genetic material. Pentachlorophenol caused several tumours, including liver and adrenal gland tumours. There was an indication that the young were more sensitive than the adult animal. The risk assessment protects against the effects noted above and other potential effects by ensuring that the level of exposure to humans is well below the lowest dose level at which these effects occurred in animal tests.

Occupational risks are not of health concern when Pentachlorophenol Treated Poles and Cross-Arms are used according to the proposed label directions, which include protective measures.

Workers installing pentachlorophenol treated poles and cross-arms, or conducting post-installation (for example, maintenance) activities, can come in direct skin contact with pentachlorophenol residues. Therefore, the label specifies that anyone working with pentachlorophenol treated poles and cross-arms must wear personal protective equipment (PPE), including leather riggers gloves or leather linesman gauntlet gloves (or rubber if lines are charged), long sleeve shirt, bib, long pants, safety glasses, Canadian Standards Association (CSA) approved safety boots, hard hat and appropriate outer wear for seasonal or inclement weather (raincoat, winter lined coat or coveralls/bibs). Taking into consideration the label statements and the limited duration of the registration (3 years), the incremental increase in risks from potential pentachlorophenol exposure to these individuals are not of health concern.

Risks to the general public were considered as part of the special review (PSRD2020-03, Special Review of Pentachlorophenol and Its Associated End-use Products, REV2022-02) and are not of health concern.

Pentachlorophenol can leach from treated poles and cross-arms to the soil adjacent to the treated wood. Pentachlorophenol may enter surface waters in limited quantities through movement of soils into surface waters through runoff, or if the treated pole is in contact with surface waters. As described in PSRD2020-03, pentachlorophenol in the environment can convert to the methylated transformation product pentachloroanisole under environmentally relevant conditions. Pentachloroanisole, in turn, can demethylate back to pentachlorophenol.

Exposures of terrestrial and aquatic organisms to pentachlorophenol and pentachloroanisole are expected to be minimal because of high sorption to soil and sediment and limited mobility in the environment. Potential risks to non-target terrestrial organisms are negligible as it is expected that exposures are limited to the soil adjacent to treated wood. The environmental risks to fish, aquatic invertebrates, and aquatic plants are also acceptable as low exposures are expected. If poles come in contact with water, any leached components are expected to remain mainly adsorbed to sediment near the pole. Furthermore, movement of pentachlorophenol into surface waters through soil runoff is expected to result in exposure concentrations below the level of concern.

Pentachlorophenol Treated Poles and Cross-Arms may contain TSMP (Toxic Substances Management Policy) Track 1 micro-contaminants identified in the List of Pest Control Product Formulants and Contaminants of Health or Environmental Concern. Risks of concern from the release of these contaminants into the environment are considered acceptable because their formation has been significantly reduced during the production process of pentachlorophenol.

Pentachlorophenol-treated utility poles and cross-arms are able to resist deterioration by wood-boring insects and fungi. This has been demonstrated over the past several decades during which time various pentachlorophenol-borne products were registered and used in Canada. A variety of tree species are used in Canada as utility poles and cross-arms. Some of these, such as Douglas-fir, are more effectively treated with an oil-borne preservative, such as pentachlorophenol.

Pentachlorophenol-treated utility poles and cross-arms are part of a stock of electrical grid infrastructure that are crucial to maintain the electrical grid and to respond to severe weather events, ensuring Canadians have access to reliable electricity.

Pentachlorophenol-treated utility poles and cross-arms will provide a stock of preserved electrical infrastructure ready to replace damaged or end of service life poles and cross-arms as well as to advance new infrastructure projects.

The registration of pentachlorophenol-treated utility poles and cross-arms is intended to ensure people and essential services in Canada have access to reliable electricity following the phase-out of the use of pentachlorophenol. This will allow the continued use of existing stocks of treated utility poles and cross-arms while the wood preservation sector transitions to the use of an alternative heavy duty wood preservative.

Labels of registered pesticide products include specific instructions for use. Directions include risk-reduction measures to protect human health and the environment. These directions must be followed by law. The key risk-reduction measures being proposed on the label of Pentachlorophenol Treated Poles and Cross-Arms to address the potential risks identified in this assessment are as follows.

To reduce the potential of workers coming into direct skin contact with pentachlorophenol,workers contacting pentachlorophenol treated poles and cross-arms must wear PPE, including leather riggers gloves or leather linesman gauntlet gloves (or rubber if lines are charged), long sleeve shirt, bib, long pants, safety glasses, CSA approved safety boots, hard hat and appropriate outer wear for seasonal or inclement weather (raincoat, winter lined coat or coveralls/bibs).

Pentachlorophenol Treated Poles and Cross-Arms is a Restricted Class product used for the purposes of transmission and distribution of electricity in Canada, for use in new line construction and replacement of damaged poles and cross-arms. The users of this product must adhere to legislation at applicable federal, provincial, territorial, and municipal levels. Additional industry guidelines for the protection of the environment are also followed. Legislation and guidelines may vary among different jurisdictions. For example, regional differences in soil types may require different installation methods and environmental protection measures. Therefore, label statements for protection of the environment will indicate that applicable legislation and industry guidelines for the protection of the environment must be followed, including for protecting soils and surface waters from contamination during all activities (including installation, storage, decommissioning, and disposal).

The following label statements are required:

Before making a final registration decision on Pentachlorophenol Treated Poles and Cross-Arms, Health Canada's PMRA will consider any comments received from the public in response to PRD2023-06. Health Canada will accept written comments on this proposal up to 45 days from the date of publication of PRD2023-06. Please forward all comments to Publications. Health Canada will then publish a Registration Decision, which will include its decision, the reasons for it, a summary of comments received on the proposed decision and Health Canada's response to these comments.

When the Health Canada makes its registration decision, it will publish a Registration Decision on Pentachlorophenol Treated Poles and Cross-Arms (based on the Science Evaluation of PRD2023-06). In addition, the test data referenced in PRD2023-06 will be available for public inspection, upon application, in the PMRA's Reading Room. For more information, please contact the PMRA's Pest Management Information Service.

"Acceptable risks" as defined by subsection 2(2) of the Pest Control Products Act.

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"Value" as defined by subsection 2(1) of the Pest Control Products Act: "the product's actual or potential contribution to pest management, taking into account its conditions or proposed conditions of registration, and includes the product's (a) efficacy; (b) effect on host organisms in connection with which it is intended to be used; and (c) health, safety and environmental benefits and social and economic impact."

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"Consultation statement" as required by subsection 28(2) of the Pest Control Products Act.

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"Decision statement" as required by subsection 28(5) of the Pest Control Products Act.

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