Proposed Registration Decision PRD2025-05, Metamitron, Brevis 150 SC, and Brevis 15 SG

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• Pest Management Regulatory Agency
• 8 August 2025
• ISSN: 1925-0886 (PDF version)
• Catalogue number: H113-9/2025-5E-PDF (PDF version)

Summary

Table of contents

• Proposed registration decision for metamitron
• What does Health Canada consider when making a registration decision?
• What is metamitron?
• Health considerations
• Environmental considerations
• Value considerations
• Measures to minimize risk
• Next steps
• Other information

Proposed registration decision for metamitron

Health Canada's Pest Management Regulatory Agency (PMRA), pursuant to subsection 28(1) of the Pest Control Products Act, is proposing registration for the sale and use of ADAMA Metamitron Technical, Brevis 150 SC, and Brevis 15 SG, containing the active ingredient metamitron, for thinning of apples and pears.

An evaluation of available scientific information found that, under the approved 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 in the full version of Proposed Registration Decision PRD2025-05, Metamitron, Brevis 150 SC, and Brevis 15 SG provides detailed technical information on the human health, environmental and value assessments of metamitron, Brevis 150 SC, and Brevis 15 SG.

What does Health Canada consider when making a registration decision?

The primary objective of the Pest Control Products Act is to prevent unacceptable risks to individuals and the environment from the use of pest control products. Health or environmental risk is considered acceptable^{Footnote 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 value^{Footnote 2} when used according to the label directions. Conditions of registration may include precautionary measures on the product label to further reduce risk.

To reach its decisions, Health Canada's PMRA applies modern, rigorous risk-assessment methods and policies. These methods consider the unique characteristics of sensitive subpopulations in humans (for example, children). They also consider the unique characteristics of 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 Health Canada's PMRA regulates pesticides, the assessment process and risk-reduction programs, please visit the Pesticides and pest management portion of Canada.ca.

Before making a final registration decision on metamitron, Brevis 150 SC, and Brevis 15 SG, Health Canada's PMRA will consider any written comments received from the public directly related to the proposed decision in PRD2025-05.^{Footnote 3} Health Canada will then publish a Registration Decision^{Footnote 4} on metamitron, Brevis 150 SC, and Brevis 15 SG, 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 PRD2025-05.

What is metamitron?

Metamitron is a conventional photosynthesis inhibiting herbicide that reduces fruit load in apple and pear when fruit set is higher than optimal.

Health considerations

Can approved uses of metamitron affect human health?

Brevis 150 SC and Brevis 15 SG, containing metamitron, are unlikely to affect your health when used according to the proposed label directions.

Potential exposure to metamitron may occur through the diet (food and drinking water), when handling and applying the end-use products, or when coming into contact with treated surfaces. 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 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.

In laboratory animals, the active ingredient metamitron was of low to moderate acute toxicity by the oral route of exposure; consequently, the signal word and hazard statement "WARNING – POISON" are required on the label. Metamitron was of low acute toxicity dermally and through inhalation exposure. It was minimally irritating to the eyes, non-irritating to the skin, and did not cause an allergic skin reaction.

The acute toxicity of the end-use product, Brevis 150 SC, containing metamitron, was low via the oral, dermal, and inhalation routes of exposure. It was minimally irritating to the eyes, non-irritating to the skin, and did not cause an allergic skin reaction.

The acute toxicity of the end-use product, Brevis 15 SG, containing metamitron, was low via the dermal and inhalation routes of exposure. It was of slight acute toxicity via the oral exposure route; consequently, the signal word and hazard statement "CAUTION – POISON" are required on the label. It was non-irritating to the skin and did not cause an allergic skin reaction. It was severely irritating to the eyes; consequently, the signal word and hazard statement "DANGER – EYE IRRITANT" are required on the label.

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 metamitron to cause neurotoxicity, immunotoxicity, chronic toxicity, cancer, reproductive and developmental toxicity, and various other effects. The most sensitive endpoints for the risk assessment were effects on offspring survival and body weight. There was no evidence of tumourigenicity. 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.

Residues in food and drinking water

Dietary risks from food and drinking water are not of health concern.

Aggregate acute dietary (food plus drinking water) intake estimates indicated that the general population and all population subgroups are exposed to less than 16% of the acute reference dose (ARfD), and therefore, are not of health concern.

Aggregate chronic dietary (food plus drinking water) intake estimates indicated that the general population and all population subgroups are exposed to less than 15% of the acceptable daily intake (ADI), and therefore, are not of health concern.

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. Given that dietary risks from the consumption of foods are shown to be acceptable when metamitron is used according to the supported label directions, MRLs are being proposed as a result of this assessment (refer to PMRL2025-15, Metamitron).

The MRLs for metamitron, determined from the acceptable residue trials conducted throughout Canada and the United States, on apples and pears, can be found in the Science Evaluation section of PRD2025-05.

Occupational risks from handling Brevis 150 SC and Brevis 15 SG

Occupational risks are not of health concern when Brevis 150 SC and Brevis 15 SG are used according to the proposed label directions, which include protective measures.

Workers mixing, loading, or applying Brevis 150 SC or Brevis 15 SG and workers entering recently treated apple or pear orchards can be exposed to metamitron residues through direct skin contact or through inhalation. Therefore, the label specifies that anyone mixing, loading, and applying Brevis 150 SC or Brevis 15 SG must wear a long-sleeved shirt, long pants, chemical-resistant gloves, chemical-resistant headwear plus socks and shoes. In addition, when handling Brevis 15 SG, workers must wear eye protection when handling the concentrate and when spraying using an open cab sprayer. The labels also require that workers do not enter or be allowed into treated apple or pear orchards during the restricted-entry intervals (REIs) of 12 hours to up to 19 days depending on the activity and the product used. Taking into consideration the label statements, the number of applications, and the duration of exposure for handlers and postapplication workers, the risks to these individuals are not of health concern.

Health risks in residential and other non-occupational environments

Risks in residential and other non-occupational environments are not of health concern when Brevis 150 SC and Brevis 15 SG are used according to the proposed label directions and the REIs are observed.

Residential exposure during pick-your-own (PYO) fruit activities in treated orchards are not of health concern.

Health risks to bystanders

Bystander risks are not of health concern when Brevis 150 SC and Brevis 15 SG are used according to the proposed label directions and spray drift restrictions are observed.

A standard label statement to protect against drift during application is on the label. Therefore, health risks to bystanders are not of concern.

Environmental considerations

What happens when metamitron is introduced into the environment?

When used according to the proposed label directions, environmental risks associated with metamitron and its associated end-use products are acceptable. 

Metamitron enters the environment when its end-use products are used as fruit thinners on apple and pear trees.

In the environment, metamitron is readily broken down in water and soil by microorganisms, as well as by sunlight in aquatic systems. In both water and soil, the major transformation product is desamino-metamitron, which also breaks down in soil and surface waters. Two additional major transformation products (M1 and M2) are formed in surface water. High amounts of carbon dioxide (CO₂) were observed to form in aquatic and terrestrial systems, indicating that complete breakdown of metamitron can occur in the environment. The small amount of metamitron that is not transformed is strongly bound to soil. Overall, metamitron and its transformation products have some potential to leach depending on soil type. Metamitron and its major transformation products are not expected to be found in air or to travel long distances in the atmosphere from the application sites; nor are they expected to accumulate in the tissues of animals. Under field conditions, both metamitron and desamino-metamitron break down and do not carry over to the following growing season.

When used according to the proposed label directions, metamitron and its major transformation products pose acceptable risk to earthworms, beneficial invertebrates, bees, birds, collembola, aquatic invertebrates, fish, aquatic plants, algae, and amphibians. Metamitron may affect non-target terrestrial plants and small wild mammals if they are exposed to high enough levels. Precautionary label statements, best management practice label statements, and spray buffer zones, as described below, are therefore required on the end-use product labels. Risks to the environment are acceptable when the end-use products are used in accordance with the label directions, and when the required risk-reduction measures are applied.

Value considerations

What is the value of Brevis 150 SC and Brevis 15 SG?

Brevis 150 SC and Brevis 15 SG are conventional herbicide products that, when applied post-bloom to apple and pear, will reduce the photosynthetic capacity of the tree, thereby causing excess fruit to fall, which in turn may contribute to an increase in the quality of the remaining fruit.

The use of Brevis 150 SC and Brevis 15 SG can be expected to complement other fruit thinning measures employed by growers and serve as an effective replacement for carbaryl that is under significant global regulatory pressures to restrict and/or eliminate its uses, including its widespread use as a chemical thinning agent in apple and pear.

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 labels of ADAMA Metamitron Technical, Brevis 150 SC, and Brevis 15 SG to address the potential risks identified in this assessment are as follows.

Key risk-reduction measures - Human health

To reduce the potential exposure of workers to metamitron through direct skin contact or inhalation, workers mixing, loading, and applying Brevis 150 SC and Brevis 15 SG and performing cleaning and repair activities must wear a long-sleeved shirt, long pants, chemical-resistant gloves, chemical-resistant headwear plus socks and shoes. In addition, when handling Brevis 15 SG, workers must wear eye protection when handling the concentrate or when spraying using an open cab sprayer. The labels also require that workers do not enter or be allowed entry into treated apple or pear orchards during the REIs of 12 hours to up to 19 days, depending on the activity and the product used. Furthermore, standard label statements to protect against drift during application are present on the labels.

Brevis 150 SC

Restricted-entry intervals (REIs) and Preharvest intervals (PHIs)

DO NOT enter or allow worker entry into treated areas during the intervals specified in the following table. Where the REI for harvesting activities and PHI differ, the longer of the two intervals must be followed when harvesting the crop.

Brevis 15 SG

Restricted-entry Intervals (REIs) and Preharvest Intervals (PHIs)

DO NOT enter or allow worker entry into treated areas during the intervals specified in the following table. Where the REI for harvesting activities and PHI differ, the longer of the two intervals must be followed when harvesting the crop.

Key risk-reduction measures - Environment

Standard label statements are required to inform users of the toxicity of metamitron to non-target terrestrial plants, small wild mammals, and aquatic plants.

Standard best management practice label statements are required to instruct users to avoid using Brevis 15 SG and Brevis 150 SC in areas more conducive to leaching to groundwater (in other words, where the soils are permeable and particularly where the water table is shallow).

Standard best management practice label statements are required to instruct users to avoid runoff of Brevis 15 SG and Brevis 150 SC into sensitive aquatic habitats.

Spray buffer zones are required to reduce the risk of spray drift to sensitive non-target terrestrial habitats.

Next steps

Before making a final registration decision on metamitron, Brevis 150 SC, and Brevis 15 SG, Health Canada's PMRA will consider any written comments received from the public that are directly related to PRD2025-05, such as comments directed to the science evaluation, in response to PRD2025-05 up to 45 days from the date of publication (8 August 2025) of PRD2025-05. Please note that, to comply with Canada's international trade obligations, consultation on the proposed MRLs will also be conducted internationally via a notification to the World Trade Organization. Please forward all comments to PMRA Publications, through the Public Engagement Portal (Public Engagement Forms – Consultation Comment). 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.

Other information

When Health Canada's PMRA makes its registration decision, it will publish a Registration Decision on metamitron, Brevis 150 SC, and Brevis 15 SG (based on the Science evaluation of PRD2025-05). In addition, the test data referenced in this consultation document will be available for public inspection, upon application, in the PMRA's Reading Room. For more information or if you have questions, please contact the PMRA's Pest Management Information Service.