Proposed Registration Decision PRD2024-08, Copper (present as cupric oxide) and Corning Guardiant Antimicrobial Particles

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Pest Management Regulatory Agency
28 November 2024
ISSN: 1925-0886 (PDF version)
Catalogue number: H113-9/2024-8E-PDF (PDF version)

Summary

Table of contents

• Proposed registration decision for copper (present as cupric oxide) and Corning Guardiant Antimicrobial Particles
• What does Health Canada consider when making a registration decision?
• What is copper (present as cupric oxide or cuprous oxide)?
• Health considerations
• Environmental considerations
• Value considerations
• Measures to minimize risk
• Next steps
• Other information

Proposed registration decision for copper (present as cupric oxide) and Corning Guardiant Antimicrobial Particles

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 Cupric Oxide, containing the active ingredient copper (present as cupric oxide) and Corning Guardiant Antimicrobial Particles containing the active ingredient copper (present as cuprous oxide), as an in-can and dry-film preservative against bacteria and yeast.

In addition, Corning Guardiant Antimicrobial Particles may also be used to formulate paints and coatings registered under the Pest Control Products Act that have residual antimicrobial effectiveness after application to indoor hard surfaces (kills 99.9% of bacteria and viruses within two hours on painted surfaces). All formulators wanting to use Corning Guardiant Antimicrobial Particles for residual indoor hard surface efficacy are responsible for registering their pesticide products under the Pest Control Products Act.

The active ingredient copper is present as cupric oxide in the technical grade active ingredient and is converted to cuprous oxide in Corning Guardiant Antimicrobial Particles.

Copper (present as cupric oxide and cuprous oxide) containing pesticides are currently registered as broad spectrum fungicides, bactericides and antifouling agents for use in antifouling paints, sanitizers, material preservatives, and wood preservatives. For details, see the Proposed Re-evaluation Decision, PRVD2009-04, Copper Pesticides, and the Re-evaluation Decision, RVD2010-05, Copper Pesticides.

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 Proposed Registration Decision PRD2024-08, Copper (present as cupric oxide) and Corning Guardiant Antimicrobial Particles provides detailed technical information on the human health, environmental and value assessments of copper (present as cupric oxide) and Corning Guardiant Antimicrobial Particles.

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 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, the 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 regulates pesticides, the assessment process and risk-reduction programs, please visit the Pesticides and pest management portion of Canada.ca website.

Before making a final registration decision on copper (present as cupric oxide) and Corning Guardiant Antimicrobial Particles, Health Canada's PMRA will consider any written comments received from the public in response to PRD2024-08.^{Footnote 3} Health Canada will then publish a Registration Decision^{Footnote 4} on copper (present as cupric oxide) and Corning Guardiant Antimicrobial Particles, 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 PRD2024-08.

What is copper (present as cupric oxide or cuprous oxide)?

Copper has well-known antimicrobial properties. Copper ions can kill bacteria and viruses by destroying lipid membranes, protein coats, and cell membranes using multiple mechanisms of action. This renders the structures of microorganisms non-functional.

Health considerations

Can approved uses of copper (present as cupric oxide or cuprous oxide) affect human health?

Copper (present as cupric oxide or cuprous oxide) is unlikely to affect human health when used according to label directions.

The active ingredient copper is present as cupric oxide in the technical grade active ingredient and is converted to cuprous oxide in the end-use 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 where 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 effect in animal testing are considered acceptable for registration.

Potential exposure to copper (present as cupric oxide or cuprous oxide) may occur when handling the product. In laboratory animals, copper (present as cupric oxide) was of low acute toxicity via the oral, dermal and inhalation routes, moderately irritating to the eye, mildly irritating to the skin and not a dermal sensitizer.

Copper is a naturally-occurring metal that is present in many foods and in drinking water. Copper is also an essential element in maintaining normal health in humans, with adverse effects more likely to result from copper deficiency rather than excess.

There was no evidence of copper being carcinogenic or resulting in any other systemic toxicity in animals having normal copper homoeostasis. Available studies in animals generally indicate that the main concern for reproductive and developmental effects is associated with copper deficiency rather than excess.

Copper, present as cuprous oxide, is characterized as being of low acute toxicity by the oral and dermal routes, highly toxic by the inhalation route, severely irritating to the eyes and skin, and not a dermal sensitizer.

The end-use product, Corning Guardiant Antimicrobial Particles, containing copper (present as cuprous oxide), is of slight acute toxicity by the oral route, low acute toxicity by the dermal and inhalation routes, mildly irritating to the eyes, non-irritating to the skin and not a dermal sensitizer.

Residues in water and food

Dietary risks from food and water are acceptable.

The end-use product, Corning Guardiant Antimicrobial Particles, is not proposed for food or feed uses. Dietary or drinking water exposure is not expected from the proposed use of copper (present as cuprous oxide) as a material preservative. Consequently, health risks from dietary exposure are acceptable for all segments of the population, including infants, children, adults and seniors.

Risks in residential and other non-occupational environments

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

Corning Guardiant Antimicrobial Particles will only be added to paints in paint manufacturing facilities. Consequently, the health risk to residents and the general public is acceptable.

Paint containing Corning Guardiant Antimicrobial Particles as an in-can preservative will be used by both professional and residential painters. Standard mitigating statements are required on paints sold in Canada.

Occupational risks from handling Corning Guardiant Antimicrobial Particles

Occupational risks are acceptable when Corning Guardiant Antimicrobial Particles is used according to the label directions, which include protective measures.

Workers handling Corning Guardiant Antimicrobial Particles can come into direct contact with copper (present as cuprous oxide) through contact with the skin or by inhalation during loading, clean-up and repair.

To protect workers from exposure to the end-use product, the label requires workers to wear a long-sleeved shirt, long pants, chemical-resistant gloves, socks and shoes during loading, clean-up and repair. Precautionary and hygiene statements on the label are considered adequate to protect individuals from occupational exposure.

The health risks to workers are acceptable when the precautionary statements on the label are observed.

Environmental considerations

An environmental assessment was not required given that the proposed major new uses for copper (present as cupric oxide) and its associated end-use product, Corning Guardiant Antimicrobial Particles (containing copper present as cuprous oxide), are only for indoor use.

Value considerations

What is the value of Corning Guardiant Antimicrobial Particles?

Corning Guardiant Antimicrobial Particles contain copper (present as cuprous oxide), which can be used to inhibit the in-can and dry-film growth of bacteria and yeast, and can kill 99.9% of bacteria and viruses on coated surfaces within two hours of exposure.

The registration of the Corning Guardiant Antimicrobial Particles, containing 27% copper present as cuprous oxide, will offer a novel in-can and dry-film preservative for use in paints, protecting against bacteria and yeast.

For use in formulating paint and coatings registered under the Pest Control Products Act that have residual antimicrobial effectiveness after application to indoor hard surfaces (kills 99.9% of bacteria and viruses within two hours on painted surfaces), Corning Guardiant Antimicrobial Particles would be applied at a rate of 52–100 g/3.78 L of paint. All formulators wanting to use Corning Guardiant Antimicrobial Particles for indoor hard surface efficacy are responsible for registering their pesticide products under the Pest Control Products Act.

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 Cupric Oxide and Corning Guardiant Antimicrobial Particles to address the potential risks identified in this assessment are as follows.

Key risk-reduction measures - Human health

The hazard signal words "WARNING – EYE IRRITANT" and "CAUTION – SKIN IRRITANT" are required on the principal display panel for Cupric Oxide and "CAUTION POISON" and "CAUTION – EYE IRRITANT" are required on the principal display panel for Corning Guardiant Antimicrobial Particles. Standard precautionary statements are also required on the labels to inform users that the TGAI causes eye and skin irritation and that the EP is harmful if swallowed, and causes eye irritation.

Workers are required to wear a long-sleeved shirt, long pants, chemical-resistant gloves, socks and shoes during loading, clean-up and repair.

To limit bystander exposure, the end-use product label requires a statement indicating only authorized access is permitted in the area during handling.

Key risk-reduction measures - Environment

The Corning Guardiant Antimicrobial Particles label will require a statement 'toxic to aquatic organisms', due to the inherent toxicity of copper and 'FOR INDOOR USE ONLY' will be added to the primary panel.

Next steps

Before making a final registration decision on copper (present as cupric oxide) and Corning Guardiant Antimicrobial Particles, Health Canada's PMRA will consider any written comments received from the public in response to PRD2024-08 up to 45 days from the date of publication (28 Novembre 2024) of PRD2024-08. 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 makes its registration decision, it will publish a Registration Decision on copper (present as cupric oxide) and Corning Guardiant Antimicrobial Particles (based on the Science Evaluation of PRD2024-08). 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.