The Canadian Environmental Protection Act (CEPA) required the Departments of Health and Environment in Canada to assess all of the approximately 23,000 chemical substances listed on the national inventory, the Domestic Substances List (DSL). The majority of these substances were identified as being in commerce between 1984 and 1986. Substances added to the inventory through the New Substance Notification regulations (NSN) were not required to be assessed again.

The Chemicals Management Plan was announced by the Government of Canada in December 2006. As part of that process, the risk assessment of 200 High Priority Substances make up part of The Challenge program to industry and other stakeholders. These 200 substances were grouped into 12 “batches” to be completed over a five-year timeline. Included in several of these batches are a number of chlorinated substances More information on the plan can be found at the government web site www.chemicalsubstanceschimiques.gc.ca.