Canadian Non-Domestic Substances List. "Environment Canada has published and continues to maintain a Non-Domestic Substances List (NDSL). This second publication is based on the United States Environmental Protection Agency's (USEPA) Toxic Substances Control Act (TSCA) Chemical Substances Inventory for 1985, and contains more than 58 000 entries. Substances that are not on the DSL but are listed on the NDSL are subject to lesser information requirements."