Notification for trisiloxane in cosmetics

Summary#

A new government notice, Significant New Activity Notice No. 21912, was published on January 25, 2025 for the chemical trisiloxane, 3-ethyl-1,1,1,3,5,5,5-heptamethyl- (CAS RN 17861-60-8). It requires companies to tell the federal environment minister before using this chemical in many cosmetics so regulators can check health risks first.

What it does#

• Declares certain new uses of the substance in cosmetics to be "significant new activities." Those uses trigger a requirement to notify the government and provide health and exposure information.
• Exemptions: uses for research and development, site-limited intermediate uses, and products made only for export are not treated as significant new activities.
• The notice excludes activities already regulated under other federal laws (for example, some pest control and feed rules).
• For each proposed significant new activity, a company must submit information at least 90 days before starting the activity. Required information includes:
  • A description of the planned use and the expected annual quantity.
  • The substance’s function in the product.
  • Existing data the company has about health and environmental effects.
  • Specific laboratory studies, including:
    • OECD Test No. 428 (in vitro skin absorption),
    • OECD Test No. 407 (28‑day repeated dose oral toxicity in rodents),
    • OECD Test No. 421 (reproduction/developmental toxicity screening).
  • These studies must follow the OECD Principles of Good Laboratory Practice.
• The government will assess the submitted information within 90 days of receiving a complete package.
• The notice sets concentration cut-offs below which some cosmetic uses are not covered:
  • hair dye at 5% by weight or less;
  • rinse-off cosmetics at 10% by weight or less;
  • foundation makeup, facial makeup remover, hair gel, or lipstick at 1% by weight or less.
• Transitional rule: between publication and January 24, 2026, the notice only applies if the activity involves more than 100 kg of the substance. After that date, the lower concentration thresholds above apply regardless of quantity.
• The notice is issued under the Canadian Environmental Protection Act, 1999 and is already in force.

Who's affected#

• Companies that make, import, formulate, distribute or sell cosmetics containing this chemical in Canada. This includes ingredient suppliers and product manufacturers.
• Retailers and distributors could be affected indirectly if suppliers need to change formulations or delay supply.
• The notice does not apply to firms using the chemical only for research and development, site-limited intermediates, or to products made solely for export.
• It’s unclear from the notice how many current products in Canada contain this specific substance at levels above the thresholds. Companies will need to check their ingredient lists and safety data.

Why it matters#

• The rule forces industry to give regulators data before expanding uses that could raise consumer exposure. That helps the government assess risks to human health.
• For business, it can mean extra testing, paperwork and a possible waiting period before launching or changing products that use the chemical. That can affect product planning and costs.
• For consumers, the measure aims to reduce the chance that harmful levels of the substance reach cosmetics sold in Canada. It gives regulators time to study possible reproductive, developmental or other health concerns before wider use.