In re Application of Enbridge Energy to Replace & Relocate Line 5 (Little Traverse Bay Bands of Odawa Indians v. Michigan Public Service Commission)

Reversing an intermediate appellate court, the Michigan Supreme Court vacated the Michigan Public Service Commission’s (PSC’s) approval of an application by Enbridge Energy Limited Partnership (Enbridge) to replace and relocate a portion of its Line 5 fuel pipeline to a tunnel beneath the Straits of Mackinac. First, the Supreme Court held the Court of Appeals should have reviewed the PSC’s approval independently and de novo. Second, the Supreme Court concluded that the PSC failed to fully assess whether the Line 5 replacement project would “factually and proximately cause Line 5’s extended operation” and that the PSC erred by considering the environmental impacts of the entire scope of alternatives while only considering the harms of replacement project. In addition, the Supreme Court found that the PSC erred by failing to consider pollution, impairment, and destruction of public trust resources in its Michigan Environmental Protection Act analysis. The Supreme Court remanded to the PSC for further proceedings. One justice partially dissented. Although he agreed that the PSC must independently consider the public trust, he wrote that the majority should have afforded a “degree of deference” to the PSC’s decision, and he disagreed with the majority’s conclusion “that the continued operation of Line 5 is itself a relevant adverse environmental effect” of the replacement project. He also wrote that the consideration of alternatives should be limited to feasible alternatives to the replacement project, not Line 5 as a whole.

The Michigan Supreme Court granted two applications for leave to appeal a February 2025 Court of Appeals decision affirming the Michigan Public Service Commission’s conditional approval of an application by Enbridge Energy Limited Partnership (Enbridge) to replace and relocate a portion of its Line 5 fuel pipeline to a tunnel beneath the Straits of Mackinac. In its order granting an application filed by Tribes and environmental organizations, the Supreme Court indicated it would consider whether the Court of Appeals erred by (1) “applying a deferential standard of review rather than determining de novo whether the proposed conduct will pollute, impair, or destroy the air, water, or state’s other natural resources or the public trust in these resources under … the Michigan Environmental Protection Act” and (2) “affirming the Michigan Public Service Commission’s limitation on the scope of the evidence to be reviewed regarding its determinations under … MEPA and its decision to exclude evidence of the history and risk of oil spills along the entire length of Line 5 in those determinations.” In the order granting a water issues-focused environmental organization’s application, the Supreme Court indicated it would consider common-law public trust doctrine issues.

Two applications were filed seeking leave to appeal the Michigan Court of Appeals decision affirming the Michigan Public Service Commission’s conditional approval of an application by Enbridge Energy Limited Partnership (Enbridge) to replace and relocate a portion of its Line 5 fuel pipeline to a tunnel beneath the Straits of Mackinac. One of the applications argued that the Court of Appeals had applied the wrong standard of review under the Michigan Environmental Protection Act (MEPA) and that the case warranted review to correct the improperly narrow scope of impacts considered in the MEPA review.