Proposed Registration Decision PRD2025-16, Formic Acid and FENNOSURF 600-C

• Pest Management Regulatory Agency
• 5 December 2025
• ISSN: 1925-0886 (PDF version)
• Catalogue number: H113-9/2025-16E-PDF (PDF version)

Summary

Table of contents

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

Proposed registration decision for formic acid

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 FENNOSURF 600-T and FENNOSURF 600-C, belonging to Kemira Water Solutions, Inc., containing the active ingredient formic acid, for bacterial control in municipal wastewater treatment and the manufacturing process of paper and paperboard.

Formic acid is currently registered as a miticide for the control of varroa mites and tracheal mites and is used for the treatment of honey bee colonies. For details, see Proposed Re-evaluation Decision PRVD2022-15, Formic Acid and Its Associated End-use Products, and Re-evaluation Decision RVD2023-05, Formic Acid and Its Associated End-use Products.

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 PRD2025-16, Formic Acid and FENNOSURF 600-C provides detailed technical information on the human health, environmental and value assessments of formic acid and FENNOSURF 600-C.

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 formic acid and FENNOSURF 600-C, Health Canada's PMRA 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 formic acid and FENNOSURF 600-C, 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 PRD2025-16.

What is formic acid?

Formic acid is a naturally occurring substance found in animals (for example, venom of ants and bees), and in plants (for example, stinging nettles). Synthetic formic acid is used world-wide for a variety of commercial uses, such as a preservative and antibacterial agent in livestock feed, a chemical intermediate in the production of various pharmaceuticals, in the tanning process for leather, and as an ingredient in commercial cleaning products.

The end-use product, FENNOSURF 600-C, containing 75% formic acid, is proposed for use with a partner end-use product containing 35% hydrogen peroxide. These products are to be used exclusively together as precursors in the production of performic acid (PFA) for bacterial control in municipal wastewater treatment and paper and paperboard manufacturing processes. Performic acid is an oxidative microbicide that functions by oxidizing organic components of microorganisms. The oxidation process denatures proteins, disrupts cell wall permeability, and oxidizes sulfhydryl and sulphur bonds in proteins, enzymes, and other metabolites, causing death of the microorganism.

Health considerations

Can approved uses of formic acid affect human health?

Formic acid is unlikely to affect human health when used according to label directions.

Potential exposure to formic acid may occur via the dermal and inhalation routes when transferring, handling, and loading the product.

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. 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 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 data, waivers based on corrosivity of the substance, and publicly available information were considered for formic acid. Formic acid is moderately acutely toxic via the oral route of exposure, highly acutely toxic via the inhalation route of exposure, corrosive to both the skin and eyes, and is a potential skin sensitizer.

When rats and mice were exposed to formic acid by the inhalation route, respiratory and olfactory epithelium irritation was noted. Mortality was also observed in mice at the highest dose tested (HDT).

Oral administration of sodium formate, the sodium salt of formic acid, in pregnant rats and rabbits did not result in maternal or fetal toxicity.

Formic acid is not expected to be mutagenic or clastogenic.

Toxicology studies and waivers due to substance corrosivity were used to inform the toxicology profile of FENNOSURF 600-C. Consequently, this end-use product is of slight acute oral toxicity, low acute inhalation toxicity, corrosive to both the eyes and skin, and is a potential skin sensitizer.

Residues in food and drinking water

Dietary risks from food and drinking water are acceptable.

There are no proposed food or feed uses for the end-use product. Consequently, dietary exposure from the proposed uses is not expected in food commodities.

While treated water may be released to rivers, lakes, or other surface water bodies, concentrations of formic acid and PFA are expected to decrease rapidly in the environment; therefore, dietary exposure from drinking water is expected to be negligible, and a dietary risk assessment was not required.

Occupational risks from handling FENNOSURF 600-C

Occupational risks are acceptable when FENNOSURF 600-C is used according to the label directions, which include protective measures.

FENNOSURF 600-C is used only concurrently with an end-use product containing hydrogen peroxide to generate PFA in situ within a closed system. Workers connect the feeder hoses from separate sealed high-density polyethylene (HDPE) totes or bulk tankers containing either FENNOSURF 600-C or the hydrogen peroxide end-use product to the Kemira Dispensing Device, which is a closed metered system that mixes the two precursor products. During loading, the potential routes of exposure are inhalation and dermal. There is no exposure expected during mixing and application, as these processes occur within a closed system. The label of the end-use product includes precautionary statements instructing workers to ensure that air concentrations of formic acid in the workplace do not exceed exposure levels established by occupational health and safety authorities in their jurisdiction, and that if values do exceed those levels, they are to wear National Institute for Occupational Safety and Health (NIOSH)-approved respiratory protection.

Postapplication exposure to formic acid and PFA may occur when uncoupling the feeder hoses, removing spent end-use product containers, or handling treated paper; however, this is expected to be negligible based on the short half-lives of the two chemicals. Additionally, the feeder hoses are automatically flushed with water after each PFA generation, and worker exposure is expected to be appropriately mitigated through wearing the required personal protective equipment (PPE), monitoring of exposure levels and observing precautionary statements.

Overall, occupational risks to workers are acceptable when the precautionary statements on the labels, which include PPE requirements, are followed.

Risks in residential and other non-occupational environments

Estimated risk for residential and other non-occupational exposure is acceptable.

There are no residential uses for FENNOSURF 600-C, as it is a commercial class product. Bystander exposure is not expected to be of concern from the use of FENNOSURF 600-C because the application occurs in a closed system in industrial settings and the label of the end-use product includes precautionary statements instructing that air concentrations of formic acid in the workplace must not exceed exposure levels established by occupational health and safety authorities in their jurisdiction. Consequently, the health risks to bystanders from the use of FENNOSURF 600-C are acceptable.

Environmental considerations

What happens when formic acid is introduced into the environment?

When users follow label directions, the environmental risks associated with formic acid are acceptable.

The use pattern of FENNOSURF 600-C is unlikely to lead to the release of formic acid or PFA to land. Thus, the risk to plants and animals on land is minimal. Formic acid and PFA may be released to rivers, lakes, or other water bodies in the environment when effluent is released from wastewater treatment plants and paper and paperboard manufacturing plants. Concentrations of formic acid and PFA in treated water are expected to decrease when treated water mixes with environmental waters. Also, bacteria are expected to break down formic acid and PFA quickly in the environment. The risk to plants and animals in water is acceptable when users follow the label directions, which include the required key risk-reduction measures.

Value considerations

What is the value of FENNOSURF 600-C?

FENNOSURF 600-C is a precursor of PFA, which is proposed to be used for bacterial control in the treatment of municipal wastewater and in the manufacturing process of paper and paperboard.

The registration of FENNOSURF 600-C as a precursor of PFA will expand the list of options available for the treatment of municipal wastewater and industrial fluids. Performic acid serves as an alternative to chemicals such as chlorine and peracetic acid, which can leave unwanted byproduct residue in the treated water and, given their slow degradation, can cause potential harm to aquatic ecosystems.

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 FENNOSURF 600-T and FENNOSURF 600-C to address the potential risks identified in this assessment are as follows.

Key risk-reduction measures - Human health

The following signal words and hazard statements are required on both the technical grade active ingredient and end-use product labels: "DANGER", "POISON", "CORROSIVE TO EYES AND SKIN", and "POTENTIAL SKIN SENSITIZER".

Standard precautionary statements are also required on the labels to inform users that the products may be fatal if swallowed or inhaled (technical grade active ingredient) or harmful if swallowed (end-use product), corrosive/e to the eyes and skin, and to warn of the potential for sensitization.

For FENNOSURF 600-C, workers are required to wear goggles or a face shield, coveralls over a long-sleeved shirt, long pants, chemical-resistant gloves, socks and chemical-resistant footwear while transferring/handling/loading the product. Postapplication workers must also wear appropriate PPE.

To limit user and bystander exposure, the end-use product label requires the following precautionary statement: "Ensure that formic acid air concentrations in the workplace do not exceed the exposure levels established by occupational health and safety authorities in your jurisdiction. If values are unknown, or exceed these levels, wear NIOSH-approved respiratory protection."

Key risk-reduction measures - Environment

Statements informing users of toxicity to aquatic organisms and that they must follow any Canadian laws related to the release of wastewaters to the environment (for example, the Fisheries Act) are required on the end-use product label.

Next steps

Before making a final registration decision on formic acid and FENNOSURF 600-C, Health Canada's PMRA will consider any written comments received from the public that are directly related to this proposed decision PRD2025-16, such as comments directed to the science evaluation, in response to this consultation document up to 30 days from the date of publication of PRD2025-16 (by 4 January 2026). If more time is required to provide comments, a request for an extension of up to 15 days can be made. Your request must be submitted in writing to the PMRA's Publications Section within the 30-day consultation period.

Please forward all comments to PMRA Publications, 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's PMRA makes its registration decision, it will publish a Registration Decision on formic acid and FENNOSURF 600-C (based on the Science evaluation section of PRD2025-16). 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.