On January 17, 2026, Environment and Climate Change Canada (ECCC) released the latest assessment results and a revised risk management document for Methylstyrenated Phenol (MSP, CAS RN 68512-30-1), proposing its classification as a "toxic substance" under Section 64 of the Canadian Environmental Protection Act (CEPA). The proposal is based primarily on the potential persistence, bioaccumulative nature, and long-term toxic effects of MSP on aquatic ecosystems.
Background
MSP is a chemical widely used in marine and heavy equipment coatings. In its initial assessment in 2008, it was determined to pose "no significant risk to the environment or human health." However, recent monitoring data show that its annual import volume in Canada has increased significantly to 10–100 tonnes, all of which is used in industrial production. Due to changes in exposure levels and emerging ecotoxicological evidence, the authorities have decided to initiate a reassessment to comprehensively review its current environmental and health risks.
Assessment Findings
New data indicate that certain components of MSP are not easily degradable in the environment, are bioaccumulative, and may pose risks to aquatic organisms even at low concentrations, including endocrine-disrupting effects. In contrast, the human health risk assessment results are more favorable. The assessment notes that while the general public may be exposed to the substance through drinking water, the current Margin of Exposure is considered sufficient to address uncertainties. Infants, due to their higher water intake relative to body weight, represent the subgroup with the highest exposure levels, but no additional health risks have been identified. Therefore, the assessment concludes that MSP does not currently pose a risk to the life or health of Canadians.
Public Consultation
Environment and Climate Change Canada, in collaboration with Health Canada, will conduct a 60-day public consultation (until March 18) to solicit feedback on the assessment conclusions and proposed risk management measures. Stakeholders may submit comments via email or through the ECCC’s "Single Window" online system.
Next Step
If the proposal is finalized, MSP will be formally added to Part 1 of Schedule 1 of the Canadian Environmental Protection Act. The government will then implement prohibitions, restrictions, or other control measures in accordance with the law.
