The Government of Canada conducted a science-based evaluation, called a screening assessment, to address the potential for harm to Canadians and to the environment from substances in the Other Polymers Group.
Under the Canadian Environmental Protection Act, 1999 (CEPA 1999), the risk posed by a substance is determined by considering both its hazardous properties (its potential to cause adverse human health or ecological effects) and the amount of exposure there is to people and the environment. A substance may have hazardous properties; however, the risk to human health or to the environment may be low depending upon the level of exposure.
As a result of the screening assessment, the Government is proposing that PHMB (CAS RN 32289-58-0 and CAS RN 27083-27-8) is harmful to human health but not to the environment.
The Government is also proposing that DGEBA-DA resin, soya alkyd resin, and polyurethane-33 are not harmful to human health or to the environment at current levels of exposure.
About these substances
The screening assessment focuses on 4 substances, collectively referred to as the Other Polymers Group under the Chemicals Management Plan (CMP). These substances are DGEBA-DA resin, PHMB (CAS RN 32289-58-0 and 27083-27-8 are used interchangeably to identify this substance), soya alkyd resin, and polyurethane-33.
These substances were previously evaluated under the Second Phase of Polymer Rapid Screening and they were identified as requiring further assessment for potential human health risks. In accordance with the rapid screening assessment, the potential for DGEBA-DA resin, PHMB, soya alkyd resin, and polyurethane-33 to cause harm to human health was further evaluated.
Soya alkyd resin and Polyurethane-33 are used as ingredients in coatings such as paint. These substances were identified as meeting criteria describing polymers of low concern. Polymers of low concern have a limited percentage of low-molecular-weight components, are chemically stable, and do not contain reactive components. They present a low ecological and human health hazard; therefore, detailed exposure to Canadians and health hazards were not described in the screening assessment for these substances.
DGEBA-DA resin and PHMB do not occur naturally in the environment.
In Canada, DGEBA-DA resin is used as a binder, sealant and reactive component in coating, automotive, and adhesive industries.
PHMB is used as an antimicrobial preservative in cosmetics, pharmaceuticals, natural health products, and other products available to consumers. PHMB may also be used in sanitizers used in food processing facilities.
Human and ecological exposures
DGEBA-DA resin was determined to have limited exposure to Canadians since its components are manufactured to react completely to form part of a stable polymer matrix.
Canadians may be exposed to PHMB through oral, dermal, and inhalation routes from a number of products including drugs, natural health products, cosmetics, and other products available for consumers as well as from food.
As soya alkyd resin and polyurethane-33 met the criteria describing polymers of low concern, detailed exposures to Canadians were not described.
The potential for ecological exposure was evaluated under the Second Phase of Polymer Rapid Screening. Available information indicated that the substances in the Other Polymers Group have low environmental exposure potential.
Key health and ecological effects (hazard)
For DGEBA-DA resin, effect on the prostate weight was considered to be the important or critical effect identified for characterizing the risk to human health.
For PHMB, the critical effect identified for characterizing the risk to human health is the potential for adverse respiratory effects. PHMB may cause irritation to the eyes and skin and may cause an inflammatory response in the respiratory tract when present at high concentrations. PHMB was also found to be a skin sensitizer.
As soya alkyd resin and polyurethane-33 met the criteria describing polymers of low concern, health hazards were not described.
Potential for ecological harm was evaluated under the Second Phase of Polymer Rapid Screening. No ecological concerns were identified for DGEBA-DA resin, and soya alkyd resin. Polyurethane-33 was classified as having moderate ecological hazard potential, and PHMB (CAS RN 32289-58-0 and CAS RN 27083-27-8) was classified as having high ecological hazard potential according to information considered in the Second Phase of Polymer Rapid Screening.
Risk assessment outcomes
Based upon available information, the risk to human health from DGEBA-DA resin, soya alkyd resin, and polyurethane-33 is low.
Based upon a comparison of levels to which Canadians may be exposed to PHMB from dermal applications and applications in which the substance may be diffused to air, and levels associated with critical health effects, it was determined that this substance may pose a risk to human health.
Considering all information presented, it was determined that there is low risk of harm to the environment from the substances in the Other Polymers Group.
As a result of the draft screening assessment, the Government is proposing that PHMB (CAS RN 32289-58-0 and CAS RN 27083-27-8) may be harmful to human health at current levels of exposure. It is also proposed that the other 3 substances are not harmful to human health at current levels of exposure.
The Government is also proposing that the substances in the Other Polymers Group are not entering the environment at concentrations that are harmful to the environment.
If the proposed conclusion is confirmed in the final screening assessment, the Government will consider adding PHMB to Schedule 1 of CEPA 1999, also called the List of Toxic Substances. The Government is also considering the following actions to address health concerns:
For cosmetics: communicating measures to reduce exposures of Canadians to PHMB from certain cosmetics, including dermally applied products and cosmetic spray applications, by describing PHMB as a prohibited or restricted ingredient on the Health Canada Cosmetic Ingredient Hotlist. The Hotlist is used to communicate that certain substances may not be compliant with requirements of the Food and Drugs Act or the Cosmetic Regulations. Under Canadian legislation, cosmetics that contain substances that are harmful to the user cannot be sold; and
For other products available to consumers: applying Significant New Activity (SNAc) provisions under CEPA 1999 that would require any proposed new manufacture, import or distribution for sale of products available to consumers containing PHMB, that constitutes a significant new activity, to be notified to the Government and to be subject for further assessment. The SNAc provisions would be applied to products from which PHMB is proposed or intended to be diffused or to be released as a vapour, mist or aerosol.
Information is being sought by the Government to inform risk management decision-making. Details can be found in the risk management scope, including where to send information during the public comment period, ending on December 2, 2020.
Risk management actions may evolve, based upon the conclusions of the final screening assessment report, or as a result of risk management actions published for other substances. This is to ensure effective, coordinated, and consistent risk management decision-making.
Substances in the Other Polymers Group may be found in products available to consumers. Canadians should follow any safety warnings and directions related to the product and dispose of products responsibly.