In Canada, environmental law is an area of jurisdiction shared between the federal government, the various provincial and territorial governments, and municipalities. This jurisdictional split arose because the Constitution of Canada, which dates back to 1867, did not specifically allocate power over the environment, leaving instead a gradual evolution of powers. Broadly speaking, the federal government has jurisdiction over federally-owned land and undertakings, fisheries waters, shipping, aviation (including airports), railroads, manufacturing, import and export of toxic substances, interprovincial and international transportation, as well as certain areas designated as being of national importance, such as ports, national security and nuclear power. Provinces regulate everything else, including emissions from industry. Municipalities in most provinces have the delegated power to pass by-laws with respect to storm and sanitary sewer discharges, pesticide use, noxious weeds, noise and certain other nuisances. The Supreme Court of Canada has held that where more than one level of government has the authority to regulate, duplication is permissible as long as there is a possibility of dual compliance, i.e., abiding by the stricter of applicable standards. In all other cases, and generally speaking, federal law trumps the others, and provincial law will be paramount over municipal law.
When doing business in Canada, it is important to keep in mind that environmental laws are not uniform among the provinces. Attempts have been made to harmonize certain standards and criteria; however, there remain many differences with which companies operating in more than one province need to be familiar.