DIDA SNAc Notice and Manganese Assessment

Summary#

This Canada Gazette issue (published October 25, 2025) includes three Environment notices under the Canadian Environmental Protection Act, 1999. It corrects an earlier item about an equivalency agreement on methane, republishes a proposal to require advance notification for new uses or imports of hexanedioic acid, diisodecyl ester (DIDA), CAS 27178-16-1, and publishes a draft assessment proposing to add manganese and its compounds to Schedule 1 and start risk-management discussions.

What it does#

• Corrects an earlier notice to say the Agreement on the Equivalency of Federal and Alberta Regulations Respecting the Release of Methane from the Oil and Gas Sector in Alberta, 2025, was made available on October 24, 2025.
• Republishes a notice of intent to amend the Domestic Substances List so that the Significant New Activity (SNAc) rules would apply to hexanedioic acid, diisodecyl ester (DIDA). If adopted, this would:
  • Require a Significant New Activity Notification (SNAN) at least 90 days before starting specified new uses or imports.
  • Target uses in consumer products, cosmetics, natural health products, and non-prescription drugs with concentration thresholds such as 84%, 15%, 10%, 5%, and 0.2% by weight depending on the product type.
  • Require notification for importation in those product categories when the total annual quantity imported by a person is greater than 10 kg.
• Publishes a draft assessment of manganese and its compounds that:
  • Proposes to conclude these substances meet one or more criteria in section 64 of CEPA and to recommend adding them to Part 2 of Schedule 1.
  • Releases a risk-management scope document to begin stakeholder discussions.
  • Reports data on manufacture and trade (for example, average imports of about 14,000 tonnes per year) and notes some drinking-water measurements above the maximum acceptable concentration of 120 µg/L in parts of Canada.

Public comment periods for the DIDA SNAc notice and the manganese draft assessment are open October 25, 2025, to December 24, 2025.

Who's affected#

• Manufacturers, importers, distributors, and formulators of products that might contain DIDA, especially makers of:
  • consumer products and automotive fluids,
  • cosmetics (including lip liners),
  • natural health products,
  • non-prescription drugs.
• Businesses that import these products into Canada in quantities above 10 kg per year.
• Chemical suppliers who will need to check product compositions and may have to notify the government before changing uses.
• Industries that handle or release manganese, including steel-related sectors, metal ore mining, pulp and paper, and wastewater treatment facilities.
• Communities with elevated manganese in drinking water, including some First Nations communities, and groups more vulnerable to manganese exposure such as infants and children under three.
• Anyone who follows chemical safety and product regulation, because both files could lead to future restrictions or new reporting and testing requirements.

Why it matters#

• For businesses: If the DIDA changes are adopted, companies will often have to tell regulators before launching or importing products that contain the chemical above low concentration thresholds. That can affect product development timelines, supply chains, and compliance work for small and large firms alike.
• For public health: The manganese draft assessment flags potential risks to brain development in young children and identifies drinking water and some consumer products as exposure sources. That can lead to new limits, guidance, or cleanup efforts where exposures are high.
• For communities and consumers: The notices open a formal window for public input and signal that federal action or new rules could follow. People living near industrial emitters or using products with these substances may see changes in monitoring, labeling, or availability of some products if risk management moves forward.
• These are proposals and draft findings. They are not final rules yet. Public comments submitted between October 25, 2025, and December 24, 2025 will be considered before any final decisions.