Background
Enbridge sought Michigan Public Service Commission approval to replace the dual Line 5 pipelines crossing the Straits of Mackinac with a new 30-inch pipeline housed in a concrete-lined tunnel beneath the lakebed. Environmental organizations and several Indian Tribes intervened in opposition, while industry and labor groups supported the project.
The PSC approved the project under Act 16 and concluded that the requirements of the Michigan Environmental Protection Act were satisfied. Its environmental analysis generally focused on the replacement segment and tunnel, although it considered greenhouse-gas emissions associated with products transported through Line 5. The PSC declined to consider the common-law public trust doctrine. The Court of Appeals affirmed, applying a deferential standard of review.
The Court’s Holding
The Michigan Supreme Court reversed the Court of Appeals, vacated the PSC’s approval order, and remanded for further proceedings. It held that courts must review an agency’s application of MEPA de novo, regardless of whether the matter began in court or through an administrative proceeding.
The Court further held that MEPA requires consideration of environmental harms factually and proximately caused by the proposed conduct. The PSC therefore had to determine whether the tunnel project would extend Line 5’s operational life and thereby cause additional environmental harms. The PSC also erred by inconsistently comparing the project with alternatives that would replace all of Line 5 and by failing separately to assess effects on public trust resources, including the public’s protected uses of the Great Lakes and their submerged lands.
Key Takeaways
- Judicial review of an agency’s application of MEPA is de novo, not deferential.
- MEPA reaches environmental harms that are both factually and proximately caused by the conduct under review; speculation or mere possibility is insufficient.
- An agency must compare the environmental effects of proposed conduct and its alternatives on a consistent basis and must separately consider harm to public trust resources.
Why It Matters
The decision requires the PSC to conduct a more complete MEPA analysis before the Line 5 tunnel project may proceed under its approval. On remand, the agency must address whether the project is likely to prolong Line 5’s operation and cause attendant harms, fairly compare alternatives, and expressly evaluate effects on public trust resources.
More broadly, the ruling establishes that Michigan courts independently review agency compliance with MEPA and clarifies that the statute’s causation inquiry may extend beyond a project’s immediate footprint when the record supports factual and proximate causation.