R v Hydro-Québec, [1997] 3 S.C.R. 213 is a leading constitutional decision of the Supreme Court of Canada. The Court held that the Canadian Environmental Protection Act, a law for the purpose of protecting the environment, constituted criminal law and was upheld as valid federal legislation. Background Hydro-Québec allegedly dumped polychlorinated biphenyls (PCBs) into the St. Maurice River in Quebec in the early 1990s. Reasons of the court The majority reasons were written by Justice La Forest, and were joined by Justices L’Heureux-Dube, Gonthier, Cory, and McLachlin. La Forest began by considering which head of power had authority over the "environment". He concluded that "environment" was not a distinct subject matter that could be allocated to either the province or the federal government, rather, it is a diffuse subject that can be divided among the two governments. La Forest considered the pith and substance of the Act. He found that the dominant feature of the Act was the "[protection] of the environment and human life and health from any and all harmful substances by regulating these substances." La Forest then considered whether the Act constituted "criminal law", which is a federal matter under section 91(27) of the Constitution Act, 1867. He observed that criminal law must contain high level of mens rea for true crimes. Laws can be disguised (known as "colourable law") as criminal in order to intrude on provincial authority. La Forest stated that the test for "colourability" is whether the law has a "legitimate public purpose" that underlies the prohibition. He found that protection of the environment constituted such a legitimate purpose. It is a subject that has international implications yet it does not preclude the provinces from regulating in the matter along with the federal government. La Forest rejects Hydro-Québec's argument that the Act was merely a regulatory scheme and did not constitute criminal law. He noted that the Act "is an effective means of avoiding unnecessarily broad prohibitions and carefully targeting specific toxic substances." The provisions of the Act are not directed at the general protection of the environment but rather targets to control dangerous and toxic substances. Regulations are needed because of the complexity of the subject and do not suggest a mere regulatory scheme. Dissent A dissenting opinion was written by Chief Justice Lamer and was joined by Justices Sopinka, Iacobucci, and Major. Lamer considered the conclusions of La Forest. He agreed that