Chlorhexidine and its salts

Information sheet

Chlorhexidine and its salts were identified as priorities for assessment through the categorization of substances on the Domestic Substances List (DSL), or were considered a priority based on other concerns. This screening assessment focuses on chlorhexidine and its salts. It includes, but is not limited to, the 4 substances identified in the table below.

Summary of publications

Summary of publications
CAS RN DSL name Final screening assessment Proposed risk management approach
55-56-1 2,4,11,13-Tetraazatetradecanediimidamide, N,N''-bis(4-chlorophenyl)-3,12-diimino- HTML HTML
56-95-1 2,4,11,13-Tetraazatetradecanediimidamide, N,N''-bis(4-chlorophenyl)-3,12-diimino-, diacetate
3697-42-5 2,4,11,13-Tetraazatetradecanediimidamide, N,N''-bis(4-chlorophenyl)-3,12-diimino-, dihydrochloride
18472-51-0 D-Gluconic acid, compound with N,N''-bis(4-chlorophenyl)-3,12-diimino-2,4,11,13-tetraazatetradecanediimidamide
Date Activity
June 29, 2019 Publication in Canada Gazette, Part I of the final screening assessment and the proposed risk management approach, and start of a 60-day public comment period on the proposed risk management approach.
August 19, 2017 Publication in Canada Gazette, Part I and start of 60-day public comment period on (a) the updated draft screening assessment and (b) the risk management scope.

Final screening assessment and risk management approach

In June 2019, the Final Screening Assessment for Chlorhexidine and its Salts was released and the related notice was published in the Canada Gazette, Part I: Vol, 153, No. 26 – June 29, 2019.

The final screening assessment concluded that chlorhexidine and its salts meet one or more of the criteria set out in section 64 of the Canadian Environmental Protection Act, 1999, therefore the Government is considering adding these substances to Schedule 1 of the Act. A proposed risk management approach was also released on this date for a 60-day public comment period.

In August 2017, the updated Draft Screening Assessment for Chlorhexidine and its Salts was released and the related notice was published in the Canada Gazette, Part I: Vol. 151, No. 33 – August 19, 2017. A risk management scope was also released in conjunction with this publication. There was a 60-day public comment period associated with these publications.

Comments and the Government's response relating to general themes on the draft screening assessment are provided in the Summary of Public Comments Received on the Draft Screening Assessment for Chlorhexidine and its Salts.


A draft screening assessment for 1 of these substances, chlorhexidine diacetate, was published in July 2013 as part of Batch 12 of the earlier Challenge Initiative of the Chemicals Management Plan (then referred to as chlorhexidine acetate). At that time, this substance was proposed not to be harmful to human health, but harmful to the environment.

After publication of the July 2013 draft screening assessment (available upon request), significant new information became available regarding other potential sources of exposure to the chlorhexidine moiety. This includes information on quantities and commercial use of chlorhexidine (CAS RN 55-56-1) and chlorhexidine digluconate (CAS RN 18472-51-0) received under phase 2 of the Domestic Substances List inventory update. Chlorhexidine and its salts may also be present in products sold in Canada. As chlorhexidine is the moiety of toxicological concern resulting from the separation in water of chlorhexidine salts, there was a gap in the evaluation of potential impacts on the environment and human health with respect to characterizing combined exposure from all potential sources of chlorhexidine.

Therefore, to consider exposure from all potential sources of the chlorhexidine moiety, chlorhexidine diacetate was removed from Batch 12 and has been included in a screening assessment of a broader group of substances, called chlorhexidine and its salts.

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