Proposed Registration Decision PRD2013-01, Chlorfenapyr

Notice to the reader: The online consultation is now closed. Comments and suggestions received during the public consultation period are being considered in the finalization of this document. The final report will be made available as soon as possible.

Pest Management Regulatory Agency
22 January 2013
ISSN: 1925-0886 (PDF version)
Catalogue number: H113-9/2013-1E-PDF (PDF version)

Summary

Table of Contents

• Proposed Registration Decision for Chlorfenapyr
• What Does Health Canada Consider When Making a Registration Decision?
• What Is Chlorfenapyr?
• Health Considerations
• Residues in Food
• Environmental Considerations
• Value Considerations
• Measures to Minimize Risk
• Next Steps
• Other Information

Proposed Registration Decision for Chlorfenapyr

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 Chlorfenapyr Technical Insecticide, Mythic Insecticide and Pylon Miticide Insecticide, containing the technical grade active ingredient chlorfenapyr. Mythic Insecticide is intended for use in limited applications to the exterior of buildings against various pests and as a pre construction and post-construction termiticide. Pylon Miticide Insecticide is intended for use on greenhouse ornamentals and greenhouse fruiting vegetables.

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 PRD2013-01, Chlorfenapyr provides detailed technical information on the human health, environmental and value assessments of Chlorfenapyr Technical Insecticide, Mythic Insecticide and Pylon Miticide Insecticide.

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 (for example, those most sensitive to environmental contaminants). 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:

• Protecting Your Health and the Environment
• Pesticide Registration Process
• Pesticide Risk Reduction Program

Before making a final registration decision on chlorfenapyr, the PMRA will consider all comments received from the public in response to Proposed Registration Decision PRD2013-01, Chlorfenapyr. The PMRA will then publish a Registration Decision on chlorfenapyr, 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 PRD2013-01, Chlorfenapyr.

What Is Chlorfenapyr?

Chlorfenapyr is a member of the pyrrole class of insecticides (Group 13) and is the active ingredient contained in the commercial class products Pylon Miticide Insecticide and Mythic Insecticide. Pylon Miticide Insecticide is an insecticide/acaricide/nematicide for use on greenhouse ornamentals and some greenhouse fruiting vegetables. Mythic Insecticide is for use in limited applications to the exterior of buildings against various pests and as a pre-construction and post-construction termiticide.

Health Considerations

Can Approved Uses of Chlorfenapyr Affect Human Health?

Products containing chlorfenapyr are unlikely to affect your health when used according to label directions.

Potential exposure to chlorfenapyr may occur through the diet, when handling and applying the product, or when entering an area that has been treated with the product. 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 products are used according to label directions.

In laboratory animals, the technical grade active ingredient chlorfenapyr was of high acute toxicity by the oral route; consequently, the hazard signal words "DANGER POISON" are required on the label. Chlorfenapyr was of low acute toxicity by the dermal route, and moderately toxic by the inhalation route. Chlorfenapyr was mildly irritating to the eyes, non-irritating to skin and did not cause an allergic skin reaction.

The acute toxicity of the end-use products Mythic Insecticide and Pylon Miticide Insecticide was moderate by the oral and inhalation routes; consequently the hazard signal words "WARNING POISON" are required on the product labels. The acute toxicity of the end-use products was low by the dermal route. The end-use products were non-irritating to the eye, minimally irritating to the skin, and did not cause allergic skin reactions.

There was no evidence to suggest that chlorfenapyr damaged genetic material. Health effects in animals given repeated doses of chlorfenapyr included reductions in body weight, body weight gain and food consumption, deaths, and effects on the liver, blood, and nervous system. Chlorfenapyr also caused tumors originating from the blood production system in rats.

When chlorfenapyr was given to pregnant or nursing animals, deaths were observed in offspring at doses that were not toxic to the mother, indicating that the young were more sensitive to chlorfenapyr than the adult animal. The risk assessment takes this sensitivity into account in determining the allowable level of human exposure to chlorfenapyr.

Deaths occurred in adult animals at lower doses when chlorfenapyr was given by the inhalation route compared to the oral route. Toxicity via the inhalation route has not been characterized in developing fetuses or in young animals, and therefore extra protective factors were applied in the risk assessment to further reduce the allowable level of human exposure to chlorfenapyr via the inhalation route.

The risk assessment protects against the effects of chlorfenapyr by ensuring that the level of human exposure is well below the lowest dose at which these effects occurred in animal tests.

Residues in Food

Dietary risks from food are not of concern

Dietary intake estimates based on the greenhouse residue trials, revealed that the children between 1-2 years old, the subpopulation which would ingest the most chlorfenapyr relative to body weight, are expected to be exposed to less than 21% of the acute reference dose, based on an intermediate refinement of the exposure. For the basic chronic dietary risk the children between 3-5 years old are expected to be the most affected subpopulation with an estimated exposure of 21 % of the acceptable daily intake. Based on these estimates, the acute and chronic dietary risk from chlorfenapyr are not of concern for all population sub-groups.

The lifetime cancer risk estimate was further refined using American monitoring data. Based on this data, the lifetime cancer risk is not of concern (9 × 10-8).

The Food and Drugs Act prohibits the sale of adulterated food, that is, food containing a pesticide residue that exceeds the established maximum residue limit (MRL). Pesticide MRLs are established for Food and Drugs Act purposes through the evaluation of scientific data under the Pest Control Products Act. Food containing a pesticide residue that does not exceed the established MRL does not pose an unacceptable health risk.

Residue trials conducted throughout Canada and the United States using chlorfenapyr on fruiting vegetables were acceptable. The proposed MRLs for this active ingredient can be found in the Science Evaluation of this Proposed Registration Decision PRD2013-01, Chlorfenapyr.

Risks in Residential and Other Non-Occupational Environments

Residential exposure after a termiticide treatment using Mythic Insecticide is not expected to result in unacceptable risk when used according to label directions. Residential exposure to individuals contacting treated outdoor surfaces is not expected to result in unacceptable risk when Mythic Insecticide is used according to label directions.

Residential exposure is not expected from use of Pylon Miticide Insecticide.

Occupational Risks From Handling Mythic Insecticide and Pylon Miticide Insecticide

Occupational risks are not of concern when Mythic Insecticide or Pylon Miticide Insecticide is used according to the label directions, which include precautionary measures, limitations on equipment usage and/or reductions in application rates.

Farmers and custom applicators who mix, load or apply Pylon Miticide Insecticide as well as workers re-entering freshly treated greenhouses can come in direct contact with productresidues on the skin or through inhalation. Therefore, the label specifies that anyone mixing/loading and applying Pylon Miticide Insecticide must wear coveralls over long-sleeved shirt, long pants, shoes and socks and chemical resistant gloves. The label also requires that workers not enter the treated greenhouse for 12 hours after application. Based on the assessment of acute inhalation hazards, workers mixing/loading/applying Pylon Miticide Insecticide must wear a respirator. Taking into consideration these precautionary statements, restrictions on the maximum application rate and reduced number of applications, limiting application equipment and limiting the amount of product used, risks to these individuals are not of concern.

Pest control operators (PCOs) who mix, load, and apply Mythic Insecticide can come into direct contact with product residues on the skin or through inhalation. Therefore, the label specifies that anyone mixing/loading and applying Mythic Insecticide must wear a long-sleeved shirt, long pants, shoes and socks, and chemical resistant gloves. Similar to the Pylon Miticide Insecticide, the assessment of acute inhalation hazards warrants that mixers, loaders and applicators wear a respirator when applying in confined spaces. PCOs using mechanically pressurized handheld equipment cannot mix/load and apply more than 80 L of product per day. The label also requires that no contact with treated areas can occur until sprays have dried.

For bystanders, exposure is considered negligible. Therefore, health risks to bystanders are not of concern.

Environmental Considerations

What Happens When Chlorfenapyr Is Introduced Into the Environment?

Chlorfenapyr is toxic to pollinators such as honeybees and beneficial arthropods (i.e. predatory mite and parasitic wasp). Chlorfenapyr is persistent and immobile in soil, and is persistent in aquatic sediment. Label instructions that caution users about the potential effects of chlorfenapyr on non-target beneficial insects are required.

Due to the intended use pattern for Mythic Insecticide (indoor and structural uses) and Pylon Miticide Insecticide (greenhouse uses), limited environmental exposure is expected. However, once it enters the terrestrial environment, it is persistent and immobile. It is stable to hydrolysis and forms only minor phototransformation and biotransformation products on soil. Chlorfenapyr phototransforms in water, with the production of one major aquatic phototransformation product (CL 357806).

Chlorfenapyr is persistent in aquatic systems, undergoing slow biotransformation, with the production of one major aquatic biotransformation product under both aerobic and anaerobic conditions (CL 312094). Based on its low volatility (low vapour pressure and Henry's law constant), chlorfenapyr residues are not expected in the air, nor is long-range aerial transport expected.

Chlorfenapyr may adversely affect non-target terrestrial invertebrates, such as pollinators and beneficial arthropods. Therefore, toxicity statements as well as instructions that direct users not to apply the product in the presence of these sensitive and important insects, are specified on the product label.

Value Considerations

What Is the Value of Pylon Miticide Insecticide?

Pylon Miticide Insecticide controls a variety of arthropod and nematode pests on ornamentals and suppresses a variety of arthropod on some greenhouse fruiting vegetables.

Chlorfenapyr is a new mode of action (MOA) for use on greenhouse ornamentals and greenhouse fruiting vegetables, and will therefore provide a new tool for rotation with currently registered products in other mode of action groups. Pylon Miticide Insecticide is the only product registered for suppression of foliar nematodes on greenhouse ornamentals and tomato hornworm and tobacco budworm on greenhouse fruiting vegetables.

What Is the Value of Mythic Insecticide?

Mythic Insecticide kills a variety of arthropod pests when applied as a crack and crevice or spot treatment to the exterior of buildings where pests may enter (for example, doors, windows, around vents). Mythic Insecticide is also a pre- and post-construction termiticide.

The active ingredient in Mythic Insecticide has a different mode of action than currently registered pest control products used in structural pest control and will contribute to resistance management. It is also an alternative to older chemistries, such as organophosphates and carbamates, registered for the same uses. In addition, Mythic Insecticide will be an additional product that can be used against structural pests for which there are few products registered in Canada, such as subterranean termites.

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 Mythic Insecticide and Pylon Miticide Insecticide to address the potential risks identified in this assessment are as follows.

Key Risk-Reduction Measures

Human Health

Because there is a concern with workers coming into direct contact with Mythic Insecticide and Pylon Miticide Insecticide on the skin or through inhalation of spray mists, anyone mixing, loading and applying these products must wear a long-sleeved shirt, long pants, shoes and socks, and chemical resistant gloves. In addition, for Pylon Miticide Insecticide, mixers/loaders and applicators must wear coveralls. The label also requires that workers not enter the treated greenhouses for 12 hours after application. The use pattern for Pylon Miticide Insecticide applied to greenhouse vegetables will be reduced to a single application per crop cycle at 0.075 g a.i./L assuming a maximum spray volume of 1000 L. Pylon Miticide Insecticide cannot be applied with mechanically pressurized handheld equipment to greenhouse ornamentals. The maximum spray volume for greenhouse ornamentals is 1500 L/ha. For Mythic Insecticide, workers must not mix, load and apply more than 80L of product/day with mechanically pressurized handheld equipment. Further to this, based on the assessment of acute inhalation hazards, workers mixing/loading Mythic Insecticide must wear a respirator and workers mixing/loading/applying Pylon Miticide Insecticide must wear a respirator.

Environment

Mitigative environmental label statements are required on all Pylon Miticide Insecticide labels. These statements will indicate the toxicity of chlorfenapyr to pollinators and beneficial arthropods, and direct users not to apply the product in their presence.

Next Steps

Before making a final registration decision on chlorfenapyr, the PMRA will consider all comments received from the public in response to Proposed Registration Decision PRD2013-01, Chlorfenapyr. The PMRA will accept written comments on this proposal up to 45 days from the date of publication of Proposed Registration Decision PRD2013-01, Chlorfenapyr. Please note that, to comply with Canada's international trade obligations, consultation on the proposed maximum residue limits (MRLs) will also be conducted internationally via a notification to the World Trade Organization. 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 chlorfenapyr (based on the Science Evaluation of Proposed Registration Decision PRD2013-01, Chlorfenapyr). In addition, the test data referenced in Proposed Registration Decision PRD2013-01, Chlorfenapyr will be available for public inspection, upon application, in the PMRA's Reading Room (located in Ottawa).