Re-evaluation decision RVD2024-01, Dodecylguanidine hydrochloride and its associated end-use products

• Pest Management Regulatory Agency
• 29 January 2024
• ISSN: 1925-1025 (PDF version)
• Catalogue number: H113-28/2024-1E-PDF (PDF version)

Summary

Table of Contents

• Re-evaluation decision for dodecylguanidine hydrochloride and associated end-use products
• Re-evaluation decision for dodecylguanidine hydrochloride
• Risk mitigation measures
• Implementation of the re-evaluation decision
• Health considerations
• Environmental considerations
• Next steps
• Other information
• Appendix I Registered products containing dodecylguanidine hydrochloride in Canada

Re-evaluation decision for dodecylguanidine hydrochloride and associated end-use products

Under the authority of the Pest Control Products Act, all registered pesticides must be re-evaluated by Health Canada's Pest Management Regulatory Agency (PMRA) to ensure that they meet current health and environmental standards and have value. The re-evaluation considers data and information from pesticide manufacturers, published scientific reports and other regulatory agencies, as well as comments received during public consultations. Health Canada applies internationally accepted risk assessment methods as well as current risk management approaches and policies. More details, on the legislative framework, risk assessment and risk management approach, are provided under the section of Evaluation Approach of the full version of Re-evaluation Decision RVD2024-01, Dodecylguanidine Hydrochloride and Its Associated End-use Products.

Dodecylguanidine hydrochloride is registered in Canada to control slime-forming bacteria and other microorganisms that form problematic biofilms on the surfaces of equipment in contactwith process waters in pulp and paper mills, cooling towers, and air washers. Dodecylguanidine hydrochloride is a non-oxidizing alternative in biofilm control and acts as a surfactant to break up biofilm then kills isolated bacteria via membrane disruption. Dodecylguanidine hydrochloride is found in co-formulation with n-alkyl dimethyl benzyl ammonium chloride or methylene bisthiocyanate in currently registered products. Currently registered products containing dodecylguanidine hydrochloride can be found in the Pesticide Product Information Database and in Appendix I.

The Proposed Re-evaluation Decision PRVD2022-16, Dodecylguanidine Hydrochloride and Its Associated End-use Products^{Footnote 1} containing the evaluation of dodecylguanidine hydrochloride and proposed decision, underwent a 90 day consultation period ending on 25 October 2022. PRVD2022-16 proposed that products containing dodecylguanidine hydrochloride are acceptable for continued registration in Canada, provided that the additional proposed risk mitigation measures are in place. The proposed risk mitigation measures included an open liquid pour application limit, updating label statements to include a definition of a closed transfer system and to wear personal protective equipment, and environmental precautionary label statements.

No comments were received during the consultation period. Therefore, this decision is consistent with the proposed re-evaluation decision stated in PRVD2022-16.

A reference list of information used as the basis for the proposed re-evaluation decision is included in PRVD2022-16; no further information was used in the final re-evaluation decision. Therefore, the complete reference list of all information used in this final re-evaluation decision is set out in PRVD2022-16.

This document (RVD2024-01) presents the final re-evaluation decision^{Footnote 2} for the re-evaluation of dodecylguanidine hydrochloride, including the required amendments (risk mitigation measures) to protect human health and the environment, as well as label amendments required to bring labels to current standards. All products containing dodecylguanidine hydrochloride that are registered in Canada are subject to this re-evaluation decision.

Re-evaluation decision for dodecylguanidine hydrochloride

Health Canada has completed the re-evaluation of dodecylguanidine hydrochloride. Under the authority of the Pest Control Products Act, Health Canada has determined that continued registration of products containing dodecylguanidine hydrochloride is acceptable. An evaluation of available scientific information found that the uses of dodecylguanidine hydrochloride products meet current standards for protection of human health and the environment and have acceptable value when used according to revised conditions of registration which includes new mitigation measures. Label amendments, as summarized below and listed in Appendix II of RVD2024-01, are required.

Risk mitigation measures

Registered pesticide product labels include specific directions for use. Directions include risk mitigation measures to protect human health and the environment and must be followed by law. The required amendments, including any revised/updated label statements and/or mitigation measures, as a result of the re-evaluation of dodecylguanidine hydrochloride, are summarized below. Refer to Appendix II of RVD2024-01 for details.

Human health

Label improvements to meet current standards:

• A standard label statement for single layer personal protective equipment (PPE) is required for all products, unless more protective statements are already present.

Risk mitigation:

To protect occupational workers from potential exposure in industrial or manufacturing settings, the following risk-reduction measures are required for continued registration of dodecylguanidine hydrochloride in Canada:

• When an open liquid pour application method is used, the maximum amount of active ingredient handled per day is limited to 16.74 kg a.i./day. When applying more than this amount per day, a closed loading and transfer system is required.
• Definition of a closed transfer system is required on all end-use product labels.

Environment

Risk mitigation:

To protect the environment, the following risk-reduction measures are required:

• An update to label statements for the protection of aquatic habitats.

Implementation of the re-evaluation decision

Regulatory Directive DIR2018-01, Policy on Cancellations and Amendments Following Re-evaluation and Special Review provides general timelines for implementation of post-market decisions.

Health considerations

When conducting human health risk assessments, risks from exposure to a pesticide are estimated by comparing potential exposures with the most relevant endpoint from toxicology studies, with standard protection factors incorporated to further protect human health, including the most sensitive population. These factors provide an inherent level of protection from exposures that could result in adverse effects to human health. Furthermore, Health Canada applies additional protection factors if warranted by the hazard profile of the pesticide or by the quality and completeness of the underlying data. When risks of concern are identified in the human health exposure scenarios, it does not necessarily mean that exposure will result in adverse effects, but mitigation measures to reduce potential risks would be required in order to support continued registration of the product/use.

Potential and relative health risks are thus considered acceptable during the general 2-year implementation period unless there is evidence from incident reports or other sources of real-world post-market surveillance data suggesting that there are adverse health effects occurring as a result of the use of the product(s) according to the currently approved label/use conditions. Other considerations may include how widely the product is used, the populations potentially exposed to the product and/or other factors.

Environmental considerations

Based on the registered use pattern, the potential for environmental exposure to dodecylguanidine hydrochloride is considered to be low and the risk is considered to be acceptable. The required label updates include label statements to inform users of the toxicity to aquatic organisms and restrictions on the discharge or release of effluents containing dodecylguanidine hydrochloride into aquatic systems. Therefore, potential environmental risks are considered acceptable during the general 2-year implementation timeline for label amendments for dodecylguanidine hydrochloride.

Taking into consideration these factors, the general 2-year implementation timeline for label amendments for pest control products containing dodecylguanidine hydrochloride is considered appropriate from a human health and environmental perspective.

Refer to Appendix I for details on specific products impacted by this decision.

Next steps

To comply with this decision, the required amendments (mitigation measures and label updates) must be implemented on all product labels no later than 24 months after the publication date of RVD2024-01. Accordingly, both registrants and retailers will have up to 24 months from the date of RVD2024-01 to transition to selling the product with the newly amended labels. Similarly, users will also have the same 24-month period from the date of RVD2024-01 to transition to using the newly amended labels, which will be available on the Public Registry.

Other information

Any person may file a notice of objection^{Footnote 3} regarding this decision on dodecylguanidine hydrochloride and its associated end-use products within 60 days from the date of publication of this Re-evaluation Decision. For more information regarding the basis for objecting (which must be based on scientific grounds), please refer to the Pesticides section of the Canada.ca website (Request a Reconsideration of Decision) or contact PMRA's Pest Management Information Service.

The relevant confidential test data on which the decision is based (as referenced in PRVD2022-16) are available for public inspection, upon application, in PMRA's Reading Room. For more information, please contact the Pest Management Information Service.

Appendix I Registered products containing dodecylguanidine hydrochloride in Canada