During the conduct of its logging operations, the respondent dumped wood waste in the waters of Beaver Cove, an area within the province of British Columbia, and was charged with contravening s. 4(1) of the Ocean Dumping Control Act. The federal legislation prohibited the dumping of any substance at sea except in accordance with the terms and conditions of a permit, the sea being defined for the purposes of the Act as including the internal waters of Canada other than fresh waters. The waters of Beaver Cove are navigable and flow into Johnstone Strait which is connected with the Pacific. At trial, the Provincial Court judge dismissed the charges. Both the trial judge and the Court of Appeal held that s. 4(1) of the Act was ultra vires Parliament. This appeal was to determine whether s. 4(1) of the Act was constitutional in its application to the dumping of waste in waters, other than fresh waters, within a province. The Supreme Court held that the appeal should be allowed. It noted that the Ocean Dumping Control Act was concerned with the dumping of substances which had an adverse effect on the marine environment and was directed to the regulation of marine pollution. The federal legislative jurisdiction under s. 91(12) of the Constitution Act, 1867 with respect to seacoast and inland fisheries, was not sufficient by itself to support the constitutional validity of s. 4(1) of the Act. While the effect on fisheries of marine pollution caused by the dumping of waste was clearly one of the concerns of the Act, it was not the only effect of such pollution with which the Act was concerned. Section 4(1) of the Ocean Dumping Control Act, however, was constitutionally valid as enacted in relation to a matter falling within the national concern doctrine of the peace, order and good government power of the Parliament of Canada. The national concern doctrine applied to matters which, although originally matters of a local or private nature in a province, had since become matters of national concern. For a matter to qualify as a matter of national concern in either sense it had to have a singleness, distinctiveness and indivisibility that clearly distinguished it from matters of provincial concern. Marine pollution, because of its predominantly extra provincial as well as international character and implications, was clearly a matter of concern to Canada as a whole. The pollution of marine waters by the dumping of substances was sufficiently distinguishable from the pollution of fresh waters by such dumping to meet the requirement of singleness or indivisibility. Marine pollution, because of the differences in the composition and action of marine waters and fresh waters, had its own characteristics and scientific considerations that distinguished it from fresh water pollution. Moreover, the distinction between salt water and fresh water as limiting the application of the Ocean Dumping Control Act met the consideration, that in order for a matter to qualify as one of national concern falling within the federal peace, order and good government power it had to have ascertainable and reasonable limits, in so far as its impact on provincial jurisdiction was concerned.