Proposed Re-evaluation Decision PRVD2016-19, Antisapstain and Joinery Uses of Propiconazole

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Pest Management Regulatory Agency
1 September 2016
ISSN: 1925-0967 (PDF version)
Catalogue number: H113-27/2016-19E-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 PMRA (PRVD2016-19) Proposed Re-evaluation Decision, Antisapstain and Joinery Uses of Propiconazole, please contact our publications office.

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

Summary

Table of Contents

Background

This document (Proposed Re-evaluation Decision PRVD2016-19, Antisapstain and Joinery Uses of Propiconazole) forms part of a wider assessment of health and environmental risks of the active ingredients used in antisapstain and joinery treatments.

In 2004, the Pest Management Regulatory Agency (PMRA) completed a re-evaluation of the occupational risks for the antisapstain uses of three antisapstain active ingredients: 2-(thiocyanomethylthio) benzothiazole (TCMTB), copper-8-quinolinolate (copper-8), and disodium octaborate tetrahydrate (boron). The occupational exposure and risk assessments were conducted for workers at lumber processing facilities such as sawmills. The re-evaluation decision (RRD2004-08) identified the need for additional data to refine the occupational risk assessments and required that a product stewardship program (with follow-up monitoring) be implemented for all registered antisapstain chemicals to reduce exposure to workers. In addition, RRD2004-08 indicated that an assessment of the environmental risks of antisapstain products would be communicated in separate documents.

In response to the 2004 decision, the registrants of antisapstain products, the Sapstain Industry Group, developed a product stewardship program, referred to as the Exposure Reduction Program (ERP). This program was approved by PMRA, implemented for all antisapstain products and follow-up occupational exposure field monitoring was conducted. The ERP included additional personal protective equipment and engineering controls, which have shown to be effective in reducing worker exposure.

There are currently five active ingredients registered as joinery wood preservatives. These active ingredients are: boron, DDAC, iodocarb, propiconazole and tebuconazole. Considering that the occupational exposure scenarios for antisapstain and joinery uses are similar, and in the interest of efficiencies and consistency in decision making, occupational risk assessments were also conducted for all joinery products using the Sapstain Industry Group’s follow-up field monitoring exposure data.

Altogether seven active ingredients registered as antisapstain and/or joinery wood preservatives required updated health and environmental risk assessments. These active ingredients are: TCMTB, copper-8, boron, DDAC, iodocarb, propiconazole, and tebuconazole. The occupational risk assessments for these seven antisapstain and joinery active ingredients have been updated using current use information, current toxicology endpoints and the follow-up field monitoring exposure data. The environmental risk assessments have been conducted using available data and information.

Proposed Re-evaluation Decision PRVD2016-19, Antisapstain and Joinery Uses of Propiconazole addresses the health and environmental risk assessments for the antisapstain and joinery uses of propiconazole. The re-evaluation of the antisapstain and joinery uses of the remaining active ingredients listed above will be communicated in separate documents.

Proposed Re-evaluation Decision for Antisapstain and Joinery Uses of Propiconazole

The PMRA has completed the health and environmental risk assessments for the antisapstain and joinery uses of propiconazole. Under the authority of Pest Control Products Act, the PMRA is proposing continued registration of the antisapstain and joinery uses of propiconazole in Canada.

An evaluation of available scientific information found that the antisapstain and joinery uses of propiconazole products are not expected to pose risks of concern to human health or the environment when used according to the proposed revised label directions. As a requirement for the continued registration of antisapstain and joinery products containing propiconazole, new risk-reduction measures are proposed.

This proposal affects the joinery and antisapstain end-use products containing propiconazole registered in Canada. Once the final re-evaluation decision is made, the registrant will be instructed on how to address any new requirements.

Proposed Re-evaluation Decision PRVD2016-19, Antisapstain and Joinery Uses of Propiconazole is a consultation document that summarizes the science evaluation for propiconazole and presents the reasons for the proposed re-evaluation decision. It also proposes additional risk-reduction measures to further protect human health and the environment.

The information in PRVD2016-19 is presented in two parts. The Overview describes the regulatory process and key points of the evaluation, while the Science Evaluation provides detailed technical information on the assessment of propiconazole.

The PMRA will accept written comments on PRVD2016-19 up to 60 days from the date of publication of this document. Please forward all comments to Publications.

What Does Health Canada Consider When Making a Re-evaluation Decision?

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 acceptable if there is reasonable certainty that no harm to human health, future generations or the environment will result from use of, or exposure to, the product under its conditions or proposed conditions of registration.

The Act also requires that products have value 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 hazard and risk assessment methods as well as policies that are rigorous and modern. These methods consider the unique characteristics of potentially sensitive subpopulations in both humans (for example, children) and organisms in the environment (for example, those most sensitive to environmental contaminants). These methods and policies also consider the nature of the effects observed and the uncertainties present when predicting the impact of pesticides. For more information on how the PMRA regulates pesticides, the assessment process and risk-reduction programs, please visit the Pesticides and Pest Management section of Health Canada’s website.

For more details on the information presented in this summary, please refer to the Science Evaluation of Proposed Re-evaluation Decision PRVD2016-19, Antisapstain and Joinery Uses of Propiconazole.

What is Propiconazole?

Propiconazole is a triazole-based fungicide that is used to control fungi. Propiconazole is registered for use in antisapstain and joinery products. In addition to its uses as an antisapstain and for joinery, propiconazole is also registered to control fungi in agriculture and turf.

Antisapstain products are wood preservatives used to prevent the growth of staining fungi in freshly cut lumber. They are applied to freshly-cut wood by dipping or spraying to achieve short-term (months) protection against staining fungi.

Wood products that have been manufactured into items such as windows and doors are referred to as joinery or millwork. These items are often used in above-ground settings where they are subject to moderate decay conditions. For this reason, wooden windows and doors are typically protected with a joinery wood preservative to prevent the growth of decay fungi and increase the service life. Unlike antisapstain treatments, which are applied to lumber for short-term protection against aesthetic damage, joinery preservatives provide long-term decay protection to wood that does not require the degree of protection provided by heavy-duty wood preservation.

Health Considerations

Can Approved Uses of Propiconazole Affect Human Health?

Antisapstain and joinery products containing propiconazole are unlikely to affect your health when used according to revised label directions.

Potential exposure to propiconazole may occur through the dermal and inhalation routes, when workers are handling and applying antisapstain and joinery products containing propiconazole or when handling the treated wood.
When assessing health risks, two key factors are considered:

  • the levels at which no health effects occur and
  • the levels to which people may be exposed.

The dose levels used to assess risks are established to protect the most sensitive human population (for example, children and nursing mothers). Only uses for which exposure is well below levels that cause no effects in animal testing are considered acceptable for continued registration.

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

In laboratory animals, propiconazole was of low to slight acute oral toxicity, low acute dermal toxicity and slightly toxic by the inhalation route. It was minimally irritating to the eye, mildly irritating to skin and a skin sensitizer.

Registrant-supplied short-, and long-term (lifetime) animal toxicity tests were assessed for the potential of propiconazole to cause neurotoxicity, immunotoxicity, chronic toxicity, cancer, reproductive and developmental toxicity, and various other effects. The most sensitive endpoints for risk assessment included effects on the liver, malformations in developing young, and gastrointestinal irritation. The risk assessment protects against the above-noted effects by ensuring that the level of human exposure is well below the lowest dose at which these effects occur in animal tests.

Risks in Residential and Other Non-Occupational Environments

Non-occupational risks are not of concern.

There are currently no registered residential uses of propiconazole antisapstain and joinery products. As such, a risk assessment for a residential handler was not required.

Occupational Risks to Mixer/Loader/Applicator and Postapplication Workers

Occupational risks are not of concern when used according to the revised label directions.

Health risks to handlers are not of concern for all scenarios. Based on the updated personal protective equipment (PPE) required as a result of the ERP for Antisapstain Chemicals (see Section 3.4.3 of the Science Evaluation of PRVD2016-19), health risk estimates associated with mixing, loading, and applying and during handling of treated wood and joinery products exceeded target dermal margins of exposure (MOEs) and are not of concern. Inhalation exposure was shown to be very low for the majority of workers and is mitigated by the use of a NIOSH-respirator for specific job tasks where there is potential for inhalation exposure, as described in the ERP. Current product labels that do not include all of the required elements of the personal protective equipment will be updated to conform to the ERP.

Postapplication risks are not of concern.

Postapplication exposure through contact with dried wood is not anticipated as antisapstains are designed to prevent the growth of staining fungi in freshly cut lumber during storage and transit and not for long-term wood protection in residential or commercial areas. Similarly, exposure to consumers from contact with treated wood is also considered to be minimal.

Joinery wood is intended for use in millwork, window and door frames and other above ground non‑structural decorative exterior wood such as soffits and fascia. Significant human exposure is not expected for this type of wood.

Environmental Considerations

What Happens When Propiconazole Is Introduced Into the Environment?

When used as an antisapstain according to the proposed label directions, propiconazole is not expected to pose risks of concern to the environment.

Antisapstains, such as propiconazole, may enter the environment by leaching from treated wood stored at treatment facilities. It may reach the aquatic environment through runoff into nearby waterbodies during rainfall events. Exposure to land organisms and their habitats is expected to be negligible. Propiconazole is broken down by microbes present in soil and is not expected to persist for long periods of time. Propiconazole mixes readily in water but is expected to move out of water and into sediments in aquatic environments where it is slowly broken down by microbes and may persist. Propiconazole is not expected to be found in air and is not expected to accumulate in the tissues of organisms or in the environment.

Propiconazole has medium to low potential to move through soil depending on the amount of organic matter in the soil and has low potential to seep into groundwater. Propiconazole is toxic to fish and aquatic invertebrates if they are exposed to sufficiently high levels. However, the mitigation measures required on the label are expected to ensure minimum exposure to aquatic organisms.

Treated wood joinery products are not subject to significant leaching. Any leaching of joinery preservative that does occur, should be limited to the area around the building in which they were installed. Therefore, due to limited environmental exposure, no quantitative environmental risk assessment was conducted for the joinery uses of propiconazole.

Furthermore, as most joinery active ingredients are also antisapstain active ingredients, the environmental risk assessment for the antisapstain use of propiconazole would be expected to cover any environmental risks posed by joinery products.

Value Considerations

What is the Value of Propiconazole in Antisapstain Treatment?

Propiconazole is one of several active ingredients currently registered in Canada for use in antisapstain products. Antisapstain products are wood preservatives used to prevent the growth of staining fungi in freshly cut lumber. These pigmented fungi consume the readily available sugars and starches as they grow throughout the sapwood. While these sapstain fungi do not reduce the strength of the wood, the aesthetic damage done can result in significant economic losses in terms of the lumber being unmarketable or reduced in value.

What is the Value of Propiconazole in Joinery Treatment?

Propiconazole is one of five active ingredients currently registered in Canada for use in joinery products. Joinery products are wood preservatives used to treat products that have been machined or milled, such as window frames or doors. While these window frames and doors tend to be sheltered from excessive rains, they are still susceptible to fungal decay. Treatment with joinery products containing propiconazole inhibits the growth of decay fungi and extends the service life of wooden joinery components.

Proposed Measures to Minimize Risk

Labels of registered pesticide products include specific instructions for use. Directions include risk-reduction measures to protect human health and the environment. Following these directions is required by law. As a result of the re-evaluation of antisapstain and joinery uses of propiconazole, the PMRA is proposing further risk-reduction measures in addition to those already identified on propiconazole product labels.

Additional Key Risk Reduction Measures

Human Health

To protect workers, additional general hygiene statements and personal protective equipment are required on all propiconazole antisapstain and joinery product labels.

Environment

In order to minimize the amount of propiconazole entering aquatic environments, wood treatment facilities for antisapstain products are to be equipped with drip pads (where wood is allowed to sit for a short drying period immediately after treatment) that are roofed and paved.

Standard precautionary label statements are required to identify environmental hazards and prevent runoff from treatment facilities to waterbodies.

Next Steps

Before making a final re-evaluation decision on the antisapstain and joinery uses of propiconazole, the PMRA will consider any comments received from the public in response to PRVD2016-19. A science-based approach will be applied in making a final decision on propiconazole. The PMRA will then publish a Re-evaluation Decision that will include the decision, the reasons for it, a summary of comments received on the proposed decision and the PMRA response to these comments.

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