Domestic Substances List: 'P' Polymer Definition Revised

Summary#

Order 2023-87-11-01 Amending the Domestic Substances List changes how certain polymers are identified on the federal chemical inventory and adds a small set of new entries. The order was registered on November 24, 2023 and takes effect on the day of registration.

What it does#

• Replaces the definition of the letter “P” after a substance number on the Domestic Substances List so that a “P” marks a polymer or biopolymer that meets one of three specific sets of size and composition rules:
  • (a) number average molecular weight greater than 10 000 Da, with less than 2% of components under 500 Da and less than 5% under 1 000 Da;
  • (b) number average molecular weight greater than 1 000 Da and equal to or less than 10 000 Da, with less than 10% of components under 500 Da and less than 25% under 1 000 Da;
  • (c) a polyester made only from reactants listed in Schedule 8 to the New Substances Notification Regulations (Chemicals and Polymers) (or their anhydrous forms), except where the reactants include both 1-butanol and fumaric or maleic acid.
• Adds two CAS-numbered substances to Part 1 of the List:
  • 1646857-41-4
  • 2041102-78-5
• Adds several entries to Part 3 of the List (marked N-P for polymers with reduced reporting), including these CAS numbers and one descriptive name:
  • 19686-4
  • 19687-5
  • 19688-6
  • 19689-7
  • 19690-8 — "Soybean oil, polymer with diethylene glycol, modified plant-based oil, ethylene glycol, polyethylene glycol, benezenedicarboxylic acid and triethylene glycol"

Who's affected#

• Manufacturers, importers and suppliers of polymers and biopolymers who check the Domestic Substances List to see if a substance is already listed.
• Companies that prepare new-substance notifications under the New Substances Notification Regulations (Chemicals and Polymers), because the revised “P” definition affects which polymers qualify for reduced regulatory requirements.
• Regulators and labs that classify or test polymers by molecular weight and composition.
• It is unclear from the order whether any broader consumer groups are directly affected; the change is mainly about how substances are listed and regulated.

Why it matters#

• The change clarifies which polymers get a “P” designation and therefore may face fewer or different notification requirements. That can shorten or simplify regulatory steps for some polymer makers.
• Adding specific CAS numbers to the List means those substances are now explicitly recorded on the federal inventory, which can affect whether new notifications are needed before importing or manufacturing them in Canada.
• For businesses, the practical impacts are about paperwork, timelines and compliance obligations. For the public, the change affects how regulators track and assess certain industrial chemicals, but the order itself does not describe health or environmental effects.