Proposed Registration Decision PRD2016-19, Octhilinone

 

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Pest Management Regulatory Agency
28 July 2016
ISSN: 1925-0886 (PDF version)
Catalogue number: H113-9/2016-19E-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 Proposed Registration Decision PRD2016-19, Octhilinone please contact our publications office.

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

Summary

Table of Contents

Proposed Registration Decision for Octhilinone

Health Canada's Pest Management Regulatory Agency (PMRA), under the authority of the Pest Control Products Act and Regulations, is proposing full registration for the sale and use of Acticide OIT Technical Industrial Microbicide and Thor Acticide 45 Mildewcide, containing the technical grade active ingredient octhilinone, to provide protection of freshly treated wood against mold and mildew growth for a period of several months.

Octhilinone is currently registered as a mildewcide for a number of materials including caulks, sealants, adhesives, plastic and leather.

An evaluation of available scientific information found that, under the approved conditions of use, the product has value and does not present an unacceptable risk to human health or the environment.

This summary describes the key points of the evaluation, while the Science Evaluation of Proposed Registration Decision PRD2016-19, Octhilinone provides detailed technical information on the human health, environmental and value assessments of Acticide OIT Technical Industrial Microbicide and Thor Acticide 45 Mildewcide.

What Does Health Canada Consider When Making a Registration 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 or exposure to the product under its 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 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, please refer to the following:

Before making a final registration decision on octhilinone, the PMRA will consider any comments received from the public in response to Proposed Registration Decision PRD2016-19, Octhilinone. The PMRA will then publish a Registration Decision on octhilinone, which will include the decision, the reasons for it, a summary of comments received on the proposed final registration decision and the PMRA's response to these comments.

For more details on the information presented in this summary, please refer to the Science Evaluation of Proposed Registration Decision PRD2016-19, Octhilinone.

What Is Octhilinone?

Octhilinone is a biocide currently registered as a preservative to prevent the growth of mold and mildew on a large number of materials ranging from paints and coatings to leather. It functions by inhibiting several specific enzymes, which results in the death of the microorganisms. The proposed use for octhilinone is as a mildewcide for wood freshly-treated with copper azole wood preservative.

Health Considerations

Can Approved Uses of Octhilinone Affect Human Health?

Thor Acticide 45 Mildewcide, containing octhilinone, is unlikely to affect your health when used according to label directions.

Potential exposure to octhilinone may occur when handling and applying the product or through contact with materials (wood) containing the product as a preservative. When assessing health risks, two key factors are considered:

  • the levels where 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 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 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, the active ingredient octhilinone was of moderate to high acute toxicity by the oral route, of slight acute toxicity by the dermal and inhalation routes, and corrosive to the eyes and skin. Octhilinone also caused an allergic skin reaction. Consequently, the hazard signal words "DANGER – POISON, CORROSIVE TO EYES AND SKIN, POTENTIAL SKIN SENSITIZER" are required on the label for the Acticide OIT Technical Industrial Microbicide.

The end-use product, Thor Acticide 45 Mildewcide, was of high acute toxicity via the oral route, of low acute toxicity via the dermal route, and of slight acute toxicity via inhalation. It was severely irritating to the skin and was considered corrosive to eyes. Thor Acticide 45 Mildewcide also caused an allergic skin reaction. Consequently, the hazard signal words "DANGER – POISON, CORROSIVE TO EYES, SEVERE SKIN IRRITANT, POTENTIAL SKIN SENSITIZER" are required on the label for the end-use product.

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 octhilinone to cause neurotoxicity, immunotoxicity, chronic toxicity, cancer, reproductive and developmental toxicity, and various other effects. The most sensitive endpoints used for risk assessment were decreased growth, organ weight changes (increases in adrenal gland and heart weight), and irritation of the respiratory tract. There was no indication that the young animal was more sensitive than the adult animal. The risk assessment protects against these and any other potential effects by ensuring that the level of exposure to humans is well below the lowest dose at which these effects occurred in animal tests.

Risks in Residential and Other Non-Occupational Environments

Estimated risks for non-occupational exposure are not of concern provided that directions specified on the label are followed.

Residential exposure to individuals contacting wood products treated with octhilinone is not expected to result in health risks of concern when Thor Acticide 45 Mildewcide is used according to label directions.

Occupational Risks from Handling Thor Acticide 45 Mildewcide

Occupational risks are not of concern when Thor Acticide 45 Mildewcide is used according to the proposed label directions, which include protective measures.

A risk assessment conducted for individuals handling Thor Acticide 45 Mildewcide and wood treated with Thor Acticide 45 Mildewcide indicated that risks are not of health concern when the product is used according to label directions.

Pesticide applicators mixing, loading and applying Thor Acticide 45 Mildewcide can come in direct contact with octhilinone on the skin or through inhalation. Therefore, the label specifies that workers must wear full-face protection, chemical-resistant coveralls over a long-sleeved shirt and long pants, chemical-resistant gauntlets (long sleeved gloves), socks and chemical-resistant footwear when handling the concentrate or dilute solution, when opening treating cylinder doors, and during cleaning, maintenance and repair activities on storage vessels and treating cylinders. In addition, workers must wear a respirator with a NIOSH-approved organic vapour-removing cartridge with a prefilter approved for pesticides, or a NIOSH-approved canister approved for pesticides, when handling the concentrate, when handling the dilute solution in poorly ventilated areas, when opening treating cylinder doors and during cleaning, maintenance and repair activities on storage vessels or treating cylinders.

There is potential for exposure to workers handling wood after treatment. To minimize exposure to these workers, the label specifies that workers must wear chemical-resistant coveralls over long-sleeved shirt and long pants, goggles or face shield, chemical-resistant gauntlets (long sleeved gloves), and chemical-resistant footwear when there is a potential of getting wet by the preservative solution, when moving loads and handling freshly treated wood. For other activities that involve working under dry conditions, a long-sleeved shirt, long pants, chemical-resistant gloves, chemical goggles and chemical-resistant footwear are required.

Environmental Considerations

What Happens When Octhilinone Is Introduced Into the Environment?

When used according to the label directions, octhilinone is not expected to pose risks of concern to the environment.

Octhilinone can enter the environment by moving out of treated wood when in contact with water. Once in the terrestrial environment, octhilinone binds to soil particles and has a low potential for moving through soil. Octhilinone is not expected to enter saltwater aquatic systems as wood treated with octhilinone is not to be used in or near saltwater. Octhilinone is non-persistent in soil and freshwater aquatic systems as it transforms in the presence of both microorganisms and light. In freshwater aquatic systems, octhilinone will move from the water column into the sediment where it is expected to degrade. Residues of octhilinone are not expected to be found in air due to its low tendency to vaporize and are not expected to accumulate in the tissues of organisms or in the environment. Octhilinone does not form any significant breakdown products in the environment.

Under controlled laboratory conditions, octhilinone can be toxic to some non-target species such as birds, small wild mammals, aquatic invertebrates, fish and algae. When octhilinone is used according to the label directions, it is expected to pose negligible risk to the organisms listed above and the resulting environmental risk is considered to be acceptable. Standard precautionary environmental hazard statements are specified on the label to minimize possible environmental impacts.

Value Considerations

What Is the Value of Thor Acticide 45 Mildewcide?

Thor Acticide 45 Mildewcide provides protection of freshly treated wood against mold and mildew growth for a period of several months.

Thor Acticide 45 Mildewcide, when applied to the treatment solution of aqueous-based copper azole wood preservatives, is capable of providing protection from mold and mildew to the freshly treated wood for a period of up to six months.

Measures to Minimize Risk

Labels of registered pesticide products include specific instructions for use. Directions include risk-reduction measures to protect human and environmental health. These directions must be followed by law.

The key risk-reduction measures being proposed on the label of Thor Acticide 45 Mildewcide to address the potential risks identified in this assessment are as follows.

Key Risk-Reduction Measures

Human Health

Because there is a concern with users coming into direct contact with octhilinone on the skin or through inhalation, workers must wear full-face protection, chemical-resistant coveralls over a long-sleeved shirt and long pants, chemical-resistant gauntlets (long sleeved gloves), socks and chemical-resistant footwear when handling the concentrate or dilute solution, when opening treating cylinder doors, and during cleaning, maintenance and repair activities on storage vessels and treating cylinders. In addition, workers must wear a respirator with a NIOSH-approved organic vapour-removing cartridge with a prefilter approved for pesticides, or a NIOSH-approved canister approved for pesticides, when handling the concentrate, when handling the dilute solution in poorly ventilated areas, when opening treating cylinder doors and during cleaning, maintenance and repair activities on storage vessels or treating cylinders. Workers must wear chemical-resistant coveralls over long-sleeved shirt and long pants, goggles or face shield, chemical-resistant gauntlets, and chemical-resistant footwear when there is a potential of getting wet by the preservative solution, when moving loads and handling freshly treated wood. For other activities that involve working under dry conditions, a long-sleeved shirt, long pants, chemical-resistant gloves, chemical goggles and chemical-resistant footwear are required.

Environment

To protect sensitive aquatic species, precautionary label statements identifying environmental hazards and preventing the use of treated wood in and near marine/estuarine environments are required on the product labels.

Next Steps

Before making a final registration decision on octhilinone, the PMRA will consider any comments received from the public in response to Proposed Registration Decision PRD2016-19, Octhilinone. The PMRA will accept written comments on PRD2016-19, Octhilinone up to 45 days from the date of publication of PRD2016-19. Please forward all comments to Publications. The PMRA will then publish a Registration Decision, which will include its decision, the reasons for it, a summary of comments received on the proposed final decision and the Agency's response to these comments.

Other Information

When the PMRA makes its registration decision, it will publish a Registration Decision on octhilinone (based on the Science Evaluation of PRD2016-19, Octhilinone). In addition, the test data referenced in PRD2016-19 will be available for public inspection, upon application, in the PMRA's Reading Room (located in Ottawa).

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