Supreme Court of Canada Sides with Alberta Court of Appeal: Impact Assessment Act Declared Unconstitutional

In Reference re Impact Assessment Act, the Supreme Court of Canada assessed the constitutionality of the federal environmental assessment scheme under the Impact Assessment Act (the “IAA”). The Supreme Court held in a majority decision that the IAA was ultra vires to the constitution, following the reasoning of the Court of Appeal of Alberta.

In 2019, the IAA was enacted by parliament. The Act allowed federal regulators to consider the potential of social and environmental impacts of various provincial infrastructure and resource projects. In 2022, the Alberta Court of Appeal held that the IAA was ultra vires the constitution as it improperly intruded on the provincial heads of power set out in section 92 and 92(A)(1) of the Constitution Act, 1867.[1]  The Court of Appeal referred two questions to the Supreme Court: 1) whether the IAA was unconstitutional, in whole or in part, as being beyond Parliament’s legislative authority, and 2) whether the regulations were unconstitutional, in whole or in part, because they applied to matters entirely within the legislative authority of the provinces under the Constitution.

The Supreme Court held that although the process under section 81 and 91 of the IAA was constitutional, the “designated projects” portion of the Act was ultra vires Parliament and thus unconstitutional. The designated projects scheme was deemed unconstitutional for two reasons. The first was that its pith and substance was not directed at regulating effects as defined in the IAA. The second was that the defined term effects within federal jurisdiction did not align with federal legislative jurisdiction.[2]

This decision affirms the foundational pillars in constitutional law, and the importance of separating the federal and provincial powers in legislation. To learn more about the Supreme Court’s reasoning in Reference re Impact Assessment, read the complete decision here.


[1]  Reference re Impact Assessment Act, 2022, ABCA 165 at para 172.

[2] Reference re Impact Assessment Act, 2023 SCC 23, para 300 to 304.


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