Proposed Registration Decision PRD2026-13, Epyrifenacil, S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide

Health Canada
Healthy Environments and Consumer Safety Branch
Pesticides Regulatory Directorate
21 August 2026
ISSN: 1925-0886 (PDF version)
Catalogue number: H113-9/2026-13E-PDF (PDF version)

Summary

Table of contents

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

Proposed registration decision for epyrifenacil

Health Canada, pursuant to subsection 28(1) of the Pest Control Products Act, is proposing registration for the sale and use of S-3100 Technical (Rapidicil Technical), S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide, containing the active ingredient epyrifenacil. S-3100 0.46 EC Herbicide is to be applied pre-plant surface to canola, field corn, spring and winter wheat, and pre-plant surface and pre-emergence to soybean. V-10488 0.94 SE Herbicide is to be applied pre-plant surface to spring wheat and pre-emergence to soybean. Both products can also be used in fall burndown and fallow land programs, to maintain bare ground non-cropland, and for industrial vegetation management (IVM).

The co-active ingredient flumioxazin (in V-10488 0.94 SE Herbicide) is currently registered for the control of weeds in numerous crops and container-grown ornamentals. For details, see Evaluation Report ERC2010-05, Flumioxazin, Proposed Registration Decision PRD2013-20, Flumioxazin, and Registration Decision RD2014-11, Flumioxazin.

The co-active ingredient pyroxasulfone (in V-10488 0.94 SE Herbicide) is currently registered for the control of weeds in numerous crops. For details, see Proposed Registration Decision PRD2012-20, Pyroxasulfone, and Registration Decision RD2016-01, Pyroxasulfone.

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 of the full version of PRD2026-13, Epyrifenacil, S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide, provides detailed technical information on the human health, environmental and value assessments of epyrifenacil, S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide.

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 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 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 epyrifenacil, S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide, Health Canada will consider any written comments received from the public directly related to the proposed decision in this consultation document.^{Footnote 3} Health Canada will then publish a Registration Decision^{Footnote 4} on epyrifenacil, S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide, 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 PRD2026-13.

What is epyrifenacil?

Epyrifenacil is an inhibitor of protoporphyrinogen oxidase (PPO) in the chlorophyll biosynthetic pathway. Inhibiting PPO in plants leads to an accumulation of phototoxic chlorophyll precursors which, in the presence of light, produce activated oxygen species that disrupt cell membrane integrity and cause necrosis of plant tissues, leading to plant death. Epyrifenacil uses a novel binding mechanism and controls weed biotypes that are resistant to other chemical families classified as PPO inhibitor herbicides. Epyrifenacil is rapidly absorbed into foliage, and unlike other PPO inhibitor herbicides, it is translocated in the plant.

Health considerations

Can approved uses of epyrifenacil affect human health?

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

Potential exposure to epyrifenacil may occur through the diet, or when handling and applying the end-use products. 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 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 technical grade active ingredient epyrifenacil was of low acute toxicity via the oral, dermal, and inhalation routes. It was minimally irritating to the eyes and skin. It did not cause an allergic skin reaction.

The acute toxicity of the end-use product S-3100 0.46 EC Herbicide, containing epyrifenacil, was low via the oral, dermal, and inhalation routes of exposure. S-3100 0.46 EC Herbicide was moderately irritating to the eyes and severely irritating to the skin. It caused an allergic skin reaction. Consequently, the signal word and hazard statements “DANGER – EYE AND SKIN IRRITANT” and “POTENTIAL SKIN SENSITIZER” are required on the label.

The acute toxicity of the end-use product V-10488 0.94 SE Herbicide, containing epyrifenacil, flumioxazin, and pyroxasulfone, was low via the oral, dermal, and inhalation routes of exposure. It did not cause an allergic skin reaction. V-10488 0.94 SE Herbicide was mildly irritating to the eyes and skin. Consequently, the signal word and hazard statement “CAUTION – EYE AND SKIN IRRITANT” is 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 epyrifenacil to cause neurotoxicity, immunotoxicity, chronic toxicity, cancer, reproductive and developmental toxicity, and various other health effects. The most sensitive endpoints for risk assessment were decreased anogenital distance and effects on the blood and the liver. There was no evidence to suggest that epyrifenacil damaged genetic material. Epyrifenacil did, however, cause liver tumours in male mice. There was no evidence of increased sensitivity of the young compared to adult animals. 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.

Occupational risks from handling S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide

Occupational risks are not of health concern when S-3100 0.46 EC Herbicide or V-10488 0.94 SE Herbicide is used according to the proposed label directions, which include protective measures.

Workers mixing, loading or applying S-3100 0.46 EC Herbicide or V-10488 0.94 SE Herbicide, and workers entering recently treated fields and non-cropland areas can be exposed to epyrifenacil residues through direct skin contact or through inhalation. Therefore, the product labels specify that anyone mixing, loading and applying the end-use products must wear the personal protective equipment specified in Appendix I, Tables 10 and 11. The labels also require that workers do not enter or be allowed into treated fields during the restricted-entry interval (REI) of 12 hours, except for non-crop areas where entry is permitted once sprays have dried. 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 from exposure to S-3100 0.46 EC Herbicide or V-10488 0.94 SE Herbicide are not of health concern when the end-use products are used according to the proposed label directions.

Health risks in residential and other non-occupational environments

Risks in residential and other non-occupational environments are not of health concern when S-3100 0.46 EC Herbicide or V-10488 0.94 SE Herbicide is used according to the proposed label directions, and restricted-entry intervals (REIs) are observed.
Residential exposure to S-3100 0.46 EC Herbicide or V-10488 0.94 SE Herbicide is not expected, as they are not proposed for use in residential areas or other non-occupational environments.

Health risks to bystanders

Bystander risks are not of health concern when S-3100 0.46 EC Herbicide or V-10488 0.94 SE Herbicideis 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 both product labels. Therefore, health risks to bystanders are not of concern when the end-use product is used according to the proposed label directions.

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 females 13–49 years old are exposed to less than 30% of the acute reference dose, 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 76%of the acceptable daily intake, and therefore are not of health concern.

On the strength of the overall information, it was determined that a threshold approach was appropriate for the cancer risk assessment based on the observed tumours. Overall, the endpoints selected for the chronic dietary risk assessment are considered protective of the findings, including potential cancer effects.

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 the 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 epyrifenacil is used according to the supported label directions, MRLs are being proposed as a result of this assessment (refer to PMRL2026-08, Epyrifenacil).

MRLs for epyrifenacil determined from the acceptable residue trials conducted throughout Canada and the United States, on soybeans, field corn, wheat, and canola can be found in the Science evaluation of PRD2026-13.

One of these epyrifenacil end-use products, V-10488 0.94 SE Herbicide, is also formulated with the active ingredients flumioxazin and pyroxasulfone. These co-active ingredients are already registered for these uses in Canada, and residues in treated commodities will be covered under the existing MRLs for each active ingredient.

Environmental considerations

What happens when epyrifenacil is introduced into the environment?

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

Epyrifenacil would enter the environment when its end-use products, S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide, are used to control listed weeds in labelled crops and non-crop areas. Epyrifenacil is quickly broken down by sunlight in shallow water and by microorganisms in soil and water to form up to 18 major transformation products. The transformation products are less toxic than epyrifenacil, although some are more persistent in the environment. The transformation products of epyrifenacil may move through soil to reach groundwater. They may also move off the treatment area in spray drift or runoff. Epyrifenacil and its transformation products are not expected to move into air in significant quantities or to accumulate in the tissues of animals.

Without risk mitigation measures, the use of epyrifenacil at the proposed rates may cause adverse effects in aquatic organisms and non-target terrestrial plants. Risk mitigation measures to reduce risks to these organisms are described below. After a scientific review of the available information, Health Canada has concluded that environmental risks from the uses of epyrifenacil are acceptable when used according to the proposed label directions, which include the required risk mitigation measures.

Value considerations

What is the value of S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide?

S-3100 0.46 EC Herbicide provides burndown control of both grass and broadleaf weeds in canola, field corn, soybean, and wheat. V-10488 0.94 SE Herbicide provides burndown control of the weeds controlled by S-3100 0.46 EC Herbicide, and residual control of the weeds controlled by flumioxazin and pyroxasulfone in soybean and wheat. Both products can also be used in fall burndown and fallow land programs, to maintain bare ground non-cropland, and for industrial vegetation management (IVM).

S-3100 0.46 EC Herbicide, a formulation of epyrifenacil, is to be applied pre-plant surface to canola, field corn, and spring and winter wheat and pre-plant surface and pre-emergence to soybean. It can also be used in fall burndown and fallow land programs, to maintain bare ground non-cropland, and as well for IVM.

It provides burndown control of both grass and broadleaf weeds at a rate range of 182–363 mL/ha in canola and fall burndown and fallow land programs, 363–726 mL/ha in field corn, soybean, spring and winter wheat, and 726–1452 mL/ha to maintain bare ground non-cropland and for IVM.

V-10488 0.94 SE Herbicide, a co-formulation of epyrifenacil with registered active ingredients flumioxazin and pyroxasulfone, is to be applied pre-plant surface to spring wheat and pre-emergence to soybean. It can also be used in fall burndown and fallow land programs, to maintain bare ground non-cropland, and for IVM. It provides burndown control of the weeds controlled by S-3100 0.46 EC Herbicide and residual control of the weeds controlled by flumioxazin and pyroxasulfone at 1.75–2.0 L/ha in soybean and in fall burndown and fallow land programs, 1.75 L/ha in spring wheat, and 1.75–3.5 L/ha to maintain bare ground non-cropland and for IVM.

S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide provide contact and systemic control of a broad-spectrum of grass and broadleaf weeds, including many that are considered to be the most damaging problematic weeds in conservation crop tillage systems. Although epyrifenacil is classified as a Group 14 mode of action herbicide, it has a unique binding mechanism, which controls weed biotypes that are resistant to other chemical families within the same mode of action group. The application of these herbicides reduces early-season weed competition to the emerging crop, allowing the crop to benefit from additional moisture, nutrients, and light that would otherwise be captured by the weeds. Weed management at this time is critical as the crop does not compete well with weeds until crop canopy closure. Starting with a clean field is one of the most important steps in conservation crop tillage weed control and cover crop management to ensure maximum yield.

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.

The key risk-reduction measures being proposed on the labels of S-3100 Technical, S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide 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 epyrifenacil through direct skin contact or inhalation of sprays, workers mixing, loading and applying S-3100 0.46 EC Herbicide or V-10488 0.94 SE Herbicide and performing cleaning and repair activities must wear the personal protective equipment presented in Appendix I, Tables 10 and 11 of PRD2026-13. The labels also require that workers do not enter or be allowed entry into treated fields during the REI of 12 hours; and do not enter or allow others to enter treated non-cropland or industrial and vegetation areas until sprays have dried. Furthermore, a standard label statement to protect against drift during application is present on the labels.

Key risk-reduction measures - Environment

The following mitigation measures are required on the labels of the end-use products, S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide:

• Precautionary statements indicating toxicity to aquatic organisms and terrestrial plants.
• Precautionary statements indicating the products contain aromatic petroleum distillates which are toxic to aquatic organisms.
• Mandatory spray buffer zones of up to 275 metres to minimize exposure of terrestrial and aquatic habitats from spray drift.
• Precautionary statements with best management practices to reduce runoff and leaching to groundwater.

Next steps

Before making a final registration decision on epyrifenacil, S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide, Health Canada will consider any written comments received from the public that are directly related to this proposed decision, such as comments directed to the Science evaluation, in response to PRD2026-13 up to 30 days from the date of publication (by 20 September 2026) of PRD2026-13. 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 Pesticides Publications Section, through the Public Engagement Portal (Public Engagement Portal 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 makes its registration decision, it will publish a Registration Decision on epyrifenacil, S-3100 0.46 EC Herbicide and V-10488 0.94 SE Herbicide (based on the Science evaluation of PRD2026-13). In addition, the test data referenced in this consultation document will be available for public inspection, upon application, in the Pesticides Regulatory Directorate’s Reading Room. For more information or if you have questions, please contact the Pesticides Information Service.

Footnotes