The Toxic Substances List under Schedule 1 of the Canadian Environmental Protection Act, 1999 (CEPA 1999), was created to list substances that have been found in the environment in sufficient quantities causing harm to humans and/or the environment. Environment Canada (EC) needs to effectively manage these substances to protect Canadians and the environment from their exposure. Through the provisions of s199 of CEPA 1999, the Environmental Emergencies Branch (EEB) was given the mandate of investigating which substances on Schedule 1 of the Act, also known as CEPA toxic substances, require environmental emergency (E2) plans, if used or stored at fixed facilities. A review of CEPA toxic substances and the requirement for environmental emergency plans covers the CEPA toxic substances that were originally investigated by the EEB, e.g., vinyl chloride, dibenzofuran, methyl bromide, benzene, acetaldehyde, acrolein, acrylonitrile, and dichloromethane, rationale for the decisions taken, as to which CEPA toxics may require E2 plans; when CEPA toxics were added to Schedule 1 and which ones have not yet been included; and substances that are recommended to require E2 plans, pollution prevention plans, or are addressed by other control measures. This is an abstract of a paper presented at the 27th Arctic and Marine Oil Spill Program Technical Seminar (Edmonton, Alberta 6/8-10/2004).