The Priority Substances List identifies substances that should be assessed on a priority basis to determine whether they are toxic and pose a risk to human health or to the environment according to the Canadian Environmental Protection Act (CEPA).

The Canadian Environmental Protection Act, 1999 (CEPA 1999) is one of the most important environmental laws in Canada governing the assessment and management of chemical substances. The purpose of the Act is to protect the environment, and the health and well-being of Canadians. A major part of the Act is to sustainably prevent pollution and address the potentially dangerous chemical substances to which they might be exposed.

The Canadian Environmental Protection Act, 1999 (CEPA 1999, section 76) requires the Ministers of the Environment and of Health to establish a Priority Substances List (PSL) that identifies substances to be assessed on a priority basis to determine whether they are toxic (as defined under Section 64 of the Act) and pose a risk to the health of Canadians or to the environment. Assessments of substances placed on the PSL are the shared responsibility of Environment Canada and Health Canada. A Priority Substance may be a chemical, a group or class of chemicals, effluents or wastes.

Assessments of the first 44 substances placed on the list (PSL1) were completed by February 1994. Following the recommendations of a multi-stakeholder Expert Advisory Panel, 25 substances were added to the list (PSL2) in 1995.

Priority Substances Assessment Program
First Priority Substances List (PSL1)
Second Priority Substances List (PSL2)
Toxic substances list: schedule 1