The DSL is an inventory of substances manufactured in, or imported into Canada on a commercial scale. A substance not on the DSL is therefore a new substance in Canada. Under the Canadian Environmental Protection Act, 1999 (CEPA), any person (individual or corporation) manufacturing a new substance in or importing a new substance into Canada must provide a new substances notification containing the information prescribed by the New Substances Notification Regulations (Chemicals and Polymers) or the New Substances Notification Regulations (Organisms). Substances on the DSL do not require notification unless they are subject to significant new activity (SNAc) requirements.

The DSL includes the original list, published in the Canada Gazette, Part II, on May 4, 1994, and all additions or deletions subsequently published in the Canada Gazette, Part II. It now contains more than 28 000 substances and can be accessed through Substances Search.