Risk management scope for poly(iminocarbonimidoyliminocarbonimidoylimino-1,6-hexanediyl), hydrochloride and poly(hexamethylenebiguanine) (PHMB)

Official title: Risk management scope for poly(iminocarbonimidoyliminocarbonimidoylimino-1,6-hexanediyl), hydrochloride and guanidine, N,N'''-1,6-hexanediylbis[N'-cyano-, polymer with 1,6-hexanediamine, hydrochloride referred to as poly(hexamethylenebiguanine) (PHMB)

Chemical Abstracts Service Registry Number (CAS RN): 27083-27-8 and 32289-58-0

Environment and Climate Change Canada

Health Canada

October 2020

Summary of proposed risk management

This document outlines the risk management options under consideration for poly(hexamethylenebiquanine) (PHMB), which has been proposed to be harmful to human health.

In particular, the Government of Canada is considering the following risk management actions:

Moreover, because certain data gaps remain, further information on the following item should be provided on or before December 2, 2020, to the contact details identified in section 8 of this document, to inform risk management decision-making:

The risk management options outlined in this Risk Management Scope document may evolve through consideration of assessments and risk management options or actions published for other Chemicals Management Plan (CMP) substances as required to ensure an effective, coordinated, and consistent risk management decision-making.

Note: The above summary is an abridged list of options under consideration to manage this substance and to seek information on identified gaps. Refer to section 3 of this document for more complete details in this regard. It should be noted that the proposed risk management option(s) may evolve through consideration of additional information obtained from the public comment period, literature and other sources.

1. Context

The Canadian Environmental Protection Act, 1999 (CEPA) (Government of Canada, 1999) provides the authority for the Minister of the Environment and the Minister of Health (the ministers) to conduct assessments to determine if substances are toxic to the environment and/or to human health based on the criteria set out in section 64 of CEPAFootnote 1 Footnote 2, and if so to manage the associated risks.

The substance poly(hexamethylenebiguanine) (PHMB) Chemical Abstracts Service Registry Number (CAS RNFootnote 3) [32289-58-0 and 27083-27-8] (alternatively CAS RN 27083-27-8), referred to throughout this document as PHMB, is included in the screening assessment of the Poly Others Group of the Chemicals Management Plan (Canada 2020).

2. Issue

Health Canada and Environment and Climate Change Canada conducted a joint scientific assessment of substances in the Other Polymers Group. A notice summarizing the scientific considerations of the draft screening assessment for these substances was published in the Canada Gazette, Part I, on October 3, 2020 (Canada 2020). Refer to theDraft Screening Assessment report for PHMB for further information.

2.1 Draft screening assessment conclusion

Based on the information available, the draft screening assessment proposes that PHMB (CAS RN 32289-58-0 and CAS RN 27083-27-8) is toxic under section 64(c) of CEPA because it is entering or may enter the environment in a quantity or concentration or under conditions that constitute or may constitute a danger in Canada to human life or health (Canada, 2020). It proposed that there was not concern for ecological harm from the substance.

The draft screening assessment also proposes that PHMB (CAS RN 32289-58-0 and CAS RN 27083-27-8) meets the persistence criteria but not the bioaccumulation criteria, as defined in the Persistence and Bioaccumulation Regulations made under CEPA (Government of Canada, 2000).

The exposure sources of concern, identified in the draft screening assessment, are based on the potential dermal sensitization from the use of cosmetics and the potential inhalation toxicity of PHMB from the use of cosmetic spray applications. In addition, there could be a concern of increased exposure if other products available to consumers, other than cosmetics, where PHMB can be diffused or released to air and potentially available for inhalation, entered the Canadian market. As such, this document focuses on these applications and exposures of greatest concern (refer to section 5).

2.2 Proposed recommendation under CEPA

On the basis of the findings of the draft screening assessment conducted pursuant to CEPA, the ministers propose to recommend that PHMB (CAS RN 32289-58-0 and CAS RN 27083-27-8) be added to the List of Toxic Substances in Schedule 1 of the ActFootnote 4.

The ministers will take into consideration comments made by stakeholders during the 60-day public comment period on the draft screening assessment report for PHMB and its associated Risk Management Scope document.

If the ministers finalize the recommendation to add PHMB to Schedule 1, risk management instruments must be proposed and finalized within a set period of time, as outlined in sections 91 and 92 of CEPA (refer to section 8 for publication timelines applicable to this group of substances).

3. Proposed risk management

3.1 Proposed human health objective

Proposed human health objectives are quantitative or qualitative statements of what should be achieved to address human health concerns.

For PHMB, the proposed objective is focused on addressing the risks and exposure sources of concern outlined in section 5 of this document. As such, the proposed human health objective for this substance is to reduce exposure of the general population to PHMB levels that are protective of human health.

3.2 Proposed risk management objectives

Proposed risk management objectives set quantitative or qualitative targets to be achieved by the implementation of risk management regulations, instruments and/or tools for a given substance or substances. In this case, the proposed risk management objectives for PHMB are:

The proposed risk management objectives may be revised in the Risk Management Approach document that will be published concurrently with the screening assessment for this substance, or in subsequent risk management documents (e.g., consultation document on proposed instrument), as the case may be.

3.3 Proposed risk management options under consideration

To achieve the proposed risk management objectives and to work towards achieving the proposed human health objective, the risk management options under consideration for PHMB are as follows:

Following the publication of this document, additional information obtained from the public comment period and from other sources will be considered, along with the information presented in this document, in the instrument selection and development processFootnote 5. The risk management options outlined in this document may also evolve through consideration of assessments and risk management options or actions published for other CMP substances to ensure effective, coordinated, and consistent risk management decision-making.

3.4 Performance measurement and evaluation

Performance measurement evaluates the ongoing effectiveness and relevance of the actions taken to manage risks from toxic substancesFootnote 6. The aim is to determine whether human health and/or environmental objectives have been met and whether there is a need to revisit the risk management approach for that substance, to ensure that risks are managed effectively over time. To achieve this, the Government of Canada will review, on a regular basis, the effectiveness of the risk management action(s) for PHMB.

The Government of Canada plans to measure the effectiveness of the risk management action(s) by collecting and analyzing data to measure progress towards meeting the risk management objective(s).

The results of performance measurement and evaluation will be used to inform whether further risk management action is warranted and will be made available to Canadians along with recommendations for further action, if applicable.

3.5 Risk management information gaps

In order to make informed decisions on the proposed risk management, interested stakeholders are invited to provide further information regarding the current quantities (in kilograms) and concentrations of PHMB used in cosmetics and other products available to consumers where PHMB can be released to air and inhaled (i.e., spray application products, products intended to result in the release the substance as a vapour mist or aerosol or products that diffuse the substance in the air).

Should stakeholders have further information to help address these gaps, they should provide it on or before December 2, 2020 to the contact identified in section 8 of this document. Such information can help inform the risk management decision-making process.

4. Background

4.1 General information on PHMB

PHMB is an organic substance which is part of the CMP Other Polymers Group. The draft screening assessment identified the substance PHMB as having two equivalent CAS RN depending on how the polymer is described; CAS RN 27083-27-8 expresses the PHMB hydrochloride in terms of its starting monomers, and CAS RN 32289-58-0 for the PHMB hydrochloride as the resultant polymer (SCCS, 2017; CIR, 2017; ECHA, 2017). It is additionally noted that PHMB may also be identified by two other CAS RNs (28757-47-3 and 1802181-67-4) outside of Canada. Additionally, PHMB may have several common names associated with it, including an International Nomenclature of Cosmetic Ingredients (INCI) name for identification in cosmetics, “polyaminopropyl biguanide”.

4.2 Current uses and identified sectors

PHMB has been included in a voluntary survey (ECCC, 2015) as well as a mandatory survey conducted under section 71 of CEPA (Canada, 2015). Total reported imports of PHMB for 2014 ranged from 100 to 1000 kg and no manufacturing activities were reported. According to the mandatory and voluntary surveys, the major use reported in Canada for PHMB is as an antimicrobial preservative in cosmetics, natural health products and topical pharmaceuticals.

PHMB is also identified as being used in cosmetics, based on notifications submitted under the Cosmetic Regulations to Health Canada (personal communication, email from the Consumer and Hazardous Products Safety Directorate, Health Canada, to the New Substances Assessment and Control Bureau, Health Canada, dated September 2017; unreferenced).

PHMB is listed in the Natural Health Products Ingredients Database with a non-medicinal role for external use only as a preservative (antimicrobial) and not permitted in sprayable formulations, and listed in the Licensed Natural Health Products Database as a non-medicinal ingredient in a limited number of currently licensed topical natural health products, such as sunscreen, pain relief ointments, lotion and contact lens solutions (LNHPD [modified 2018], NHPID [modified 2018]). PHMB is also listed in the internal Drug Product Database as a non-medicinal ingredient in over the counter disinfectants in Canada (personal communication, email from the Therapeutic Products Directorate, Health Canada, to the New Substances Assessment and Control Bureau, Health Canada, dated December 2017; unreferenced).

Globally, PHMB was also identified as a preservative and antimicrobial agent in cosmetics, personal care products, wet wipes, hand washes, pharmaceuticals and contact lens solutions. The substance is also used to disinfect medical utensils, farm equipment and may be used as a component in sanitizers for disinfecting various surfaces.

5. Exposure sources and identified risks

Direct exposures from use of cosmetic products were evaluated. Product scenarios that result in the highest levels of potential exposure for each substance by the dermal and inhalation routes, or sentinel scenarios, were presented in the screening assessment. The critical health effects associated with PHMB identified in the draft screening assessment (Canada, 2019) are dermal sensitization and inhalation toxicity.

In the assessment, dermal exposure to PHMB in body moisturizer was identified as a potential concern for skin sensitization. Given the information available, it is proposed that the dermal exposure to cosmetics may pose a risk of dermal sensitization in adults and children as the concentrations in these products are higher than levels at which sensitization can occur.

Inhalation exposure was also considered, but was not found to be a concern at current levels of exposure when used in non-spray applications given PHMB has a low vapour pressure and not expected to evaporate from a product. However, if PHMB is used in products where it is dispersed into the air or released as a vapour, mist or aerosol, these are considered forms that may pose an inhalation risk to human health. Cosmetic spray applications containing PHMB are available to Canadians.

No current sources of exposure other than cosmetics were identified as a concern in the draft screening assessment (Canada, 2019). It was found that an analogous substance to PHMB, polyhexamethylene guanidine phosphate (PHMG-P), is an antimicrobial with similar product applications suspected to be responsible for serious adverse health effects from humidifier disinfectants in Korea (Kim, 2016). To date, other types of spray products (e.g., humidifier disinfectants, air fresheners or other such products available to consumers) containing PHMB are not known to be in use in Canada, however there may be a concern for increased exposure should these products become available in Canada.

6. Risk management considerations

6.1 Alternatives and alternate technologies

It is not known whether there are safe alternatives available to replace PHMB in cosmetic or disinfectant applications. Consideration will be given to the likelihood that its presence in these products is for functional purposes as a preservative or disinfectant.

6.2 Socio-economic and technical considerations

Socio-economic factors will be considered in the selection process for a regulation and/or instrument respecting preventive or control actions, and in the development of the risk management objectives(s). Socio-economic factors will also be considered in the development of regulations, instrument(s) and/or tool(s) as identified in the Cabinet Directive on Regulation (TBS, 2018) and the guidance provided in the Treasury Board document Assessing, Selecting, and Implementing Instruments for Government Action (TBS, 2007).

7. Overview of existing risk management

7.1 Related Canadian risk management context

Domestically, risk management actions for PHMB include:

7.2 Pertinent international risk management context

Internationally, PHMB is subject to the following risk management actions:

United States

European Union

7.3 Regulatory alignment

Canada is aligned in regulating the preservative/anti-microbial use of PHMB. By taking action on PHMB in cosmetics, Canada would be aligning with similar actions in the EU.

8. Next steps

8.1 Public comment period

Industry and other interested stakeholders are invited to submit comments on the content of this Risk Management Scope or other information that would help to inform decision-making (such as outlined in section 3.2).

The Risk Management Approach document, which will outline and seek input on the proposed risk management instrument(s), will be published at the same time as the final screening assessment report. At that time, there will be further opportunity for consultation.

Comments and information submissions on the Risk Management Scope should be submitted to the address provided below:

Environment and Climate Change Canada
Gatineau, Quebec  K1A 0H3
Telephone: 1-800-567-1999 (in Canada) or 819-938-3232
Fax: 819-938-5212

Email: eccc.substances.eccc@canada.ca

Companies who have a business interest in PHMB are encouraged to identify themselves as stakeholders. The stakeholders will be informed of future decisions regarding PHMB and may be contacted for further information.

8.2 Timing of actions

Electronic consultation on the draft screening assessment report and Risk Management Scope: October 3, to December 2, 2020. This should include the submission of public comments, additional studies or information on PHMB.

Publication of responses to public comments on the draft screening assessment report and Risk Management Scope:  concurrent to the publication of the screening assessment and, if required, the Risk Management Approach document. 

Publication of responses to public comments on the Risk Management Approach, if applicable and if required, the proposed instruments: At the latest, 24-month from the date on which the Ministers recommended that PHMB be added to Schedule 1 of CEPA.

Consultation on the proposed instrument if required: 60-day public comment period starting upon publication of the proposed instrument 

Publication of the final instruments, if required: At the latest, 18-month from the publication of the proposed instrument 

These are planned timelines, and are subject to change. Please consult the schedule of risk management activities and consultations for updated information on timelines.

9. References

Canada.  2000.  Canadian Environmental Protection Act, 1999: Persistence and Bioaccumulation Regulations, P.C. 2000-348, 23 March 2000, SOR/2000-107. 

Canada. 2015. Treasury Board of Canada Secretariat. Red Tape Reduction Act.. S.C. 2015, c.12.

[Canada] Canada, Dept. of the Environment. 2015. Canadian Environmental Protection Act, 1999Notice with respect to certain polymers on the Domestic Substances List. Canada Gazette, Part I, vol. 146, no. 30, Supplement.

Canada. 2017. Consolidated Food and Drug Regulations [PDF]. C.R.C., c. 870. Last amended on June 17, 2017 [Current as of September 14, 2017]. 

Canada. 2020. Dept. of the Environment, Dept. of Health. Draft Screening Assessment for the Other Polymers Group.

 [CIR] Cosmetic Ingredient Review. 2017. Safety assessment of Polyaminopropyl Biguanide as used in cosmetics. [PDF]. p. 1-41. [accessed 2018 Aug 17]

[CPSR], Cosmetic Products (Safety) Regulations 2008. Schedule 6: List of Preservatives which Cosmetic Products may Contain. United Kingdom.  

[EC]. European Commission. 2009.  Commission Regulation (EC) No. 1223/2009 of the European Parliament and of the Council on 30 November 2009 concerning cosmetic products.

[ECCC] Environment and Climate Change Canada. 2015. Data collected from Follow up on your submission for certain polymers under DSL IU2 (February 2015). Data prepared by ECCC, Health Canada; Existing Substances Program.

[ECHA] European Chemicals Agency. 2017. Registered substances database; search results for CAS RN 55818-57-0. Helsinki (FI): ECHA.

Kim H.-R., Hwang G.-W., Naganuma A., and Chung K.-H., 2016, Adverse Health effects of humidifier disinfectants in Korea: lung toxicity of polyhexamethylene guanidine phosphate. The journal of Toxicological Sciences 41(6) 711-717. 

[LNHPD] Licensed Natural Health Products Database [database]. [modified 2018-02-06]. Ottawa (ON): Health Canada.

[NHPID] Natural Health Products Ingredients Database [database]. [modified 2018-11-09]. Ottawa (ON): Health Canada.

Scientific Committee on Consumer Safety (SCCS) 2017, Opinion on Polyaminopropyl Biguanide (PHMB)- Submission III [PDF]- European Commission SCCS/1581/16.

[TBS] Treasury Board of Canada Secretariat. 2007. Assessing, Selecting, and Implementing Instruments for Government Action.

[TBS] Treasury Board of Canada Secretariat.2012. Red Tape Reduction Action Plan.

[TBS] Treasury Board of Canada Secretariat. 2018. Cabinet Directive on Regulation. Ottawa (ON): Government of Canada. [accessed 2018 Aug 29].

[US eCFR] United States Code of Federal Regulations. 2018a. Title 40, Part 180 (Tolerances and Exemptions for Pesticide Chemical Residues in Food), Subpart 180.1280. 

[US eCFR] United States Code of Federal Regulations. 2018b. Title 21: Part 170 (Food Additives), Subpart 170.39

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