Background
Enbridge Energy Limited Partnership sought approval from the Michigan Public Service Commission to replace the portion of its Line 5 pipeline crossing the Straits of Mackinac. The project would decommission the existing dual pipelines and place a new 30-inch pipeline inside a concrete-lined tunnel beneath the lakebed. Environmental organizations and Indian Tribes intervened in opposition, while labor and propane-industry groups supported the project.
The PSC approved the project under 1929 PA 16 and concluded that it satisfied the Michigan Environmental Protection Act. Its MEPA analysis generally focused on the replacement pipeline and tunnel rather than the environmental effects of Line 5 as a whole, although it considered greenhouse-gas emissions associated with products transported through the pipeline. The PSC also declined to analyze the common-law public trust doctrine. The Michigan Court of Appeals affirmed, and the opponents appealed.
The Court’s Holding
The Michigan Supreme Court held that courts must review an agency’s application of MEPA de novo, independently examining the legal issues and record rather than deferring to the agency’s MEPA determination. It further held that MEPA requires consideration of environmental harms factually and proximately caused by the conduct at issue, a fair comparison between those harms and the environmental effects of feasible alternatives, and separate consideration of potential harm to public trust resources.
Applying those principles, the Court concluded that the PSC should have determined whether constructing the replacement tunnel and pipeline would factually and proximately extend Line 5’s operational life and thereby cause additional environmental harm. The PSC also used inconsistent scopes when comparing the project with alternatives and failed to determine the project’s effects on public trust resources, including the public’s interests in the Great Lakes and submerged lands. The Court reversed the Court of Appeals, vacated the PSC’s approval order, and remanded for further proceedings; it did not finally decide whether the project may be approved after the required analysis.
Key Takeaways
- Judicial review of an agency’s MEPA determination is de novo, even when the matter began as an administrative proceeding.
- MEPA reaches environmental harms that are factually and proximately caused by the proposed conduct, requiring a case-specific inquiry rather than speculation about merely possible effects.
- An agency must compare the environmental effects of the proposed conduct and its alternatives on a consistent basis and must separately evaluate harm to public trust resources.
Why It Matters
The decision clarifies that Michigan agencies cannot confine MEPA review to a project’s immediate physical footprint when the project may proximately cause broader environmental consequences. For major infrastructure projects, agencies must determine the full causally connected scope of likely harm before deciding whether a feasible and prudent, less environmentally harmful alternative exists.
The ruling also confirms an independent judicial role in reviewing agency compliance with MEPA and makes public trust impacts—particularly effects on the Great Lakes, their submerged lands, and public uses such as fishing, hunting, and navigation—a required part of that analysis.