Proposed Re-evaluation Decision PRVD2017-15, N-Octyl bicycloheptene dicarboximide (MGK-264) and Its Associated End-use Products

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Pest Management Regulatory Agency
29 September  2017

ISSN: 1925-0967 (PDF version)
Catalogue number: H113-27/2017-15E-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 Re-evaluation Decision PRVD2017-15, N-Octyl bicycloheptene dicarboximide (MGK-264) and Its Associated End-use Products please contact our publications office.

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

Summary

Table of Contents

In Canada, pesticides are regulated under the Pest Control Products Act, administered by Health Canada’s Pest Management Regulatory Agency (PMRA). All pesticides are registered (that is, approved) if a rigorous scientific assessment indicates that the health and environmental risks are acceptable and the products have value. The Pest Control Products Act also contains provisions for post-market reviews of registered pesticides, namely re-evaluation and special reviews, to assess whether pesticides continue to meet Health Canada’s health and environmental standards, and whether they can continue to be used in Canada.

As part of the decision making process, before making a final decision, the PMRA consults with the members of the public and other interested stakeholders on all proposed major decisions such as new registrations, re-evaluations and special reviews. The PMRA encourages the public and stakeholders to participate in the consultation process. The proposed decisions are made based on the information available at the time, and the PMRA will consider the comments and information received during consultation using a science-based approach before making a final decision. The final decision will be published on the Pesticides and Pest Management portion of Canada.ca, and it will include a summary of the comments received during the consultation and the PMRA’s responses to the comments.

The registration status of products and conditions of use of pesticide products on the market are not impacted by proposed re-evaluation or special review decisions. This may be the case only when final decisions are made. However, at any point during the re-evaluation or special review of a pesticide, the Pest Control Products Act allows the PMRA to cancel or amend the registration of registered pest control products, if there are reasonable grounds to believe this is necessary to deal with a situation that endangers human health or safety or the environment.

Proposed Re-evaluation Decision for N-Octyl bicycloheptene dicarboximide (MGK-264)

Using all currently available information and the most recent risk assessment methods, the PMRA has identified potential risks of concern for people (adults, youth and children) that may be exposed to MGK-264 while entering treated residential areas. As a result, the PMRA proposes measures to reduce potential risks to acceptable levels.

Any additional data/information submitted during the consultation period to further refine the health risk assessment will be considered, and may or may not result in a change to this proposal.

This Proposed Re-evaluation Decision (PRVD2017-15) is a consultation document that summarizes the science evaluation for MGK-264 and presents the reasons for the proposed re-evaluation decision.

This consultation document (Proposed Re-evaluation Decision PRVD2017-15, N-Octyl bicycloheptene dicarboximide (MGK-264) and Its Associated End-use Products) 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 MGK-264.

The PMRA will accept written comments on this proposal up to 90 days from the date of publication of PRVD2017-15. Please forward all comments to Publications.

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

The PMRA’s pesticide re-evaluation program considers potential risks, as well as value, of pesticide products to ensure they meet modern standards established to protect human health and the environment. Regulatory Directive DIR2016-04, Management of Pesticides Re-evaluation Policy, presents the details of the current re-evaluation approach.

For more details on the information presented in this summary, please refer to the Science Evaluation of PRVD2017-15.

What is MGK-264?

MGK-264 is an insecticide synergist that is always co-formulated with one or more active ingredients belonging to synthetic pyrethroids and pyrethrins. It enhances the pesticide properties of other insecticides. MGK-264, co-formulated with other pyrethroids or pyrethrins, is registered to manage a wide spectrum of insect pests in stored food and feed, structures, companion animals, human habitat and recreational areas, human skin, clothing and proximal sites, and residential outdoors. Domestic-class products are applied using pressurized spray cans, roll-ons, pet shampoos and pump sprayers. Commercial-class products are applied using foggers, ultra-low volume equipment, pressurized sprayers and automated aerosol dispensers.

Health Considerations

Can Approved Uses of MGK-264 Affect Human Health?

Products containing MGK-264 are unlikely to affect your health when used according to the proposed label directions.

Potential exposure to MGK-264 may occur through the diet (food and drinking water), while handling and applying products containing MGK-264, or during contact with treated surfaces or animals. When assessing health risks, two key factors are considered:

  • the levels at which no health effects occur in animal testing 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). 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 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, MGK-264 was of low acute toxicity by the oral, dermal and inhalation routes. It was mildly irritating to the skin and to the eyes and did not cause an allergic reaction when applied to the skin.

For the re-evaluation, short- and long-term (lifetime) animal toxicity tests as well as information from the published scientific literature were assessed for the potential of MGK-264 to cause neurotoxicity, immunotoxicity, chronic toxicity, cancer, reproductive and developmental toxicity, and various other effects. The most sensitive endpoints used for risk assessment were effects on the liver, kidney, thyroid, and on bodyweight. Repeated inhalation exposure to MGK-264 affects the upper respiratory tract. There was no indication that young animals were more sensitive to health effects from MGK-264 than adult animals, or that MGK-264 damaged genetic material. However, extended dosing resulted in benign liver tumours in mice, and a slight increase in the incidence of thyroid tumours in rats. The risk assessment protects against the effects noted above and any other potential effects by ensuring that the levels of human exposure is well below the lowest level at which these occurred.

Pesticide Residues in Food and Drinking Water

Dietary risks from food and drinking water are not of concern when products containing MGK-264 are used according to the proposed label directions.

Reference doses define levels to which an individual can be exposed over a single day (acute) or lifetime (chronic) and expect no adverse health effects. Generally, dietary exposure from food and water is acceptable if it is less than 100% of the acute reference dose (ARfD) or chronic reference dose (acceptable daily intake or ADI). An ADI is an estimate of the level of daily exposure to a pesticide residue that, over a lifetime, is believed to have no significant harmful effects.

Dietary exposure to MGK-264 may occur from its use in areas where food can be handled (such as food handling establishments, restaurants), processed (such as processing facilities) or stored (such as storage warehouses). The use of MGK-264 on livestock intended for food production was not supported by the technical registrant; therefore, this use was not considered in the dietary assessment.

Dietary exposure to MGK-264 was estimated for the general population and different subpopulations using anticipated residues from simulated trials in food handling establishments and warehouses, and drinking water concentrations obtained from modelling. No acute and chronic risks of concern were identified. 

The acute dietary exposure estimates (from food and drinking water) at the 95th percentile represent 4% of the ARfD for the general population and range from 2% (for adults aged 50+ years and females 13-49 years old) to 8% (for children 1-2 years old) of the ARfD for all population subgroups. The chronic dietary exposure estimate for the general population represents 13% of the ADI. Chronic exposure estimates for population subgroups range from 10% (for females aged 13-49 years and adults aged 50+ years) to 38% of the ADI (for children 1-2 years old). Thus, acute and chronic dietary risks are not of concern.

The PMRA proposes to add label statements to reduce potential residues in or on food, and to prohibit application to livestock intended for food production.

The Food and Drugs Act prohibits the sale of adulterated food; that is, food containing a pesticide residue that exceeds the specified maximum residue limit (MRL). Pesticide MRLs are specified for Food and Drugs Act purposes through the evaluation of scientific data under the Pest Control Products Act. Each MRL value defines the maximum concentration in parts per million (ppm) of a pesticide allowed in or on certain foods and serves as a food safety standard. The Canadian Food Inspection Agency is responsible for monitoring the Canadian food supply for pesticide residues and the determination of compliance with MRLs specified by Health Canada.

Residues of MGK-264 in all commodities are currently regulated under Subsection B.15.002(1) of the Food and Drugs Regulations, which requires that residues do not exceed 0.1 ppm (General MRL). No change to this regulatory status is being proposed.

Risks in Residential and Other Non-Occupational Environments

Risks are not of concern for people applying domestic products containing MGK-264 in or around homes or directly to animals.

People may be exposed to MGK-264 while applying domestic-class products in or around homes or directly to animals. No risks of concern to residential handlers were identified.

For some uses, risks are of concern when people are entering certain residential areas previously treated with products containing MGK-264. As a result, the PMRA proposes measures to reduce potential risks to acceptable levels, such as the cancellation of certain uses and domestic products.

People may be exposed to MGK-264 by dermal contact and inhalation, while performing activities in treated residential areas or contacting treated animals. This includes areas and animals treated by residential handlers using domestic-class products, as well as residential areas and animals treated by commercial applicators. Children may also be exposed to MGK-264 when playing on treated surfaces or with treated animals, and subsequently ingesting the product as a result of hand- or object-to-mouth transfer.

For children, risks of concern were identified from inhalation exposure when entering certain residential areas previously treated with products containing MGK-264. Risks of concern were also identified for adults, youth and children from inhalation exposure to the aerosols present immediately following indoor space spray applications. As a result, the PMRA proposes measures to reduce potential risks to acceptable levels. These measures are listed in Proposed Measures to Minimize Risk.

Aggregate risks are not of concern when the above-noted proposed mitigation measures are considered.

Aggregate exposure is the total exposure to a single pesticide that may occur from food, drinking water, residential and other non-occupational sources, and from all known or plausible exposure routes (oral, dermal and inhalation). No aggregate risks of concern were identified for MGK-264 when the above-noted proposed mitigation measures are considered. 

Occupational Risks to Handlers and Postapplication Workers

Risks are not of concern when workers mix, load and apply products containing MGK-264 according to the proposed label directions.

Risks to workers associated with mixing, loading and applying activities are not of concern when mitigation measures (personal protective equipment, including chemical-resistant gloves and a respirator) are considered. No measured exposure data were available for application with handheld foggers/mistblowers, or handheld ultra-low-volume aerosol generators/mechanical aerosol generators (space sprays). As such, it is proposed to prohibit this application equipment on related product labels.

Risks are not of concern for workers entering sites or handling animals that were previously treated with products containing MGK-264 according to the proposed label directions.

Occupational postapplication risk assessments for MGK-264 consider exposure to workers entering treated sites (for example, food processing plants, warehouses, office buildings) or handling treated animals. No risks of concern were identified provided that workers do not enter the treated site until two hours after space spray applications.

Environmental Considerations

What Happens When MGK-264 Is Introduced into the Environment?

When used according to label directions, products containing MGK-264 are not expected to pose risks of concern to the environment.

MGK-264 enters the environment in the form of spray droplets, but breaks down rapidly once in the air. It is, therefore, unlikely that MGK-264 will persist long enough to reach soil or water. The chemical properties of MGK-264 indicate that it may accumulate in animal tissues, but this is not expected since MGK-264 is applied as an ultra-low volume spray mist, which involves putting very small amounts of liquid into the air as a fine mist of droplets. When applied in this manner, MGK-264 will not persist in the air long enough to deposit onto soil or water, and will not be available for bioaccumulation.

No risks of concern to organisms or the environment were identified during the risk assessment.

Value Considerations

What is the Value of MGK-264?

MGK-264 is a synergist that is used to increase the effectiveness of other active ingredients belonging to the pyrethroid and pyrethrins group. The use of synergists when co-formulated with other active ingredients improves the potency of the other insecticides, thus reducing the amount of these insecticides required to manage the insect pests.

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. These directions must be followed by law. As a result of the re-evaluation of MGK-264, the PMRA proposes further risk-reduction measures.

Human Health

To protect homeowners and those entering treated residential and commercial areas, the following measures are proposed:

For domestic-class products:

  • Cancellation of dust products
  • Cancellation of aerosol products for use as a metered release space spray
  • Cancellation of space spray uses for aerosol products 
  • Maximum guarantee limited to 0.4% MGK-264 for aerosol products registered for indoor treatment of fleas, ticks, and carpet beetles
  • Label directions to include definition of broadcast and spot/band treatment, unless similar information or more restrictive application instructions are already present

For commercial-class products:

  • Maximum space spray application rate limited to 0.055 g a.i./m3 for liquid formulations in certain residential areas (dwellings such as houses, apartments, or in guest rooms of hotels and motels)
  • Maximum guarantee limited to 3.3% MGK-264 for aerosol products for use as a metered release space spray
  • Prohibit aerosol products for use as a metered release space spray in areas where children may be present for more than four hours per day
  • Entry into treated sites in both residential and commercial areas following an indoor space spray application must not occur until two hours after application. The commercial applicator is responsible for notifying workers, the homeowner, and others of this requirement. 
  • Label directions to include definition of broadcast and spot/band treatment, unless similar information or more restrictive application instructions are already present

To protect mixer/loader/applicators, the following measures are proposed:

  • Prohibit the use of handheld ultra-low-volume aerosol generators/mechanical aerosol generators for space sprays
  • Prohibit the use of handheld foggers/mistblowers
  • Additional protective equipment when mixing, loading or applying by handheld equipment or truck-mounted sprayers

To protect bystanders from spray drift, the following measures are proposed:

  • Statement to promote best management practices to minimize human exposure from spray drift or spray residues resulting from drift in non-target areas.

To protect consumers from potential residues in or on food, the following measures are proposed:

  • All commercial-class labels to include the statement: “Application on livestock intended for food production is prohibited.”
  • All labels to include the statement: “Cover or remove exposed food and food handling surfaces prior to application.”

To protect human health, the PMRA proposes to limit the maximum guarantee for certain products. In order to retain products that need to be reformulated, registrants would be required to provide a scientific rationale and/or efficacy data to demonstrate that the insecticidal efficacy of their products is not impacted at the reduced MGK-264 guarantee.

Environment

  • No risk mitigation measures are proposed.

International Regulatory Status of MGK-264

The PMRA routinely works collaboratively with other member countries in the Organisation for Economic Co-operation and Development (OECD) on the regulation of pesticides. As part of the re-evaluation of an active ingredient, the PMRA takes into consideration recent developments and new information on the status of a pesticide in other jurisdictions. MGK-264 is currently acceptable for use in other OECD member countries, including Australia and the United States. No decision by an OECD member country to prohibit all uses of MGK-264 for health or environmental reasons has been identified at this time.

Next Steps

During the consultation period, registrants and stakeholder organizations may submit further data that could be used to refine risk assessments (exposure or use information), which could result in revised risk-reduction measures. Stakeholders who are planning to provide information of this type are advised to contact the PMRA early in the consultation period, for advice on studies or information that could be submitted to help refine the relevant risk assessments.

Before making a final re-evaluation decision on MGK-264, the PMRA will consider all comments received from the public in response to PRVD2017-15. 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’s response to these comments.

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