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 two existing pipelines on or above the lakebed and place a new 30-inch pipeline inside a concrete-lined tunnel beneath the Straits.
Indian Tribes and environmental organizations opposed the project, arguing that the Commission’s review under the Michigan Environmental Protection Act was too narrow. The Commission approved the project after generally limiting its review to the replacement segment and tunnel, finding no feasible and prudent alternative, and declining to consider the public trust doctrine. The Michigan Court of Appeals affirmed.
The Court’s Holding
The Michigan Supreme Court held that courts must review an agency’s application of the Michigan Environmental Protection Act de novo. The Court of Appeals therefore erred by deferring to the Commission’s environmental determination instead of independently reviewing the legal issues and record.
The Court further held that the Act requires consideration of environmental harms factually and proximately caused by the proposed conduct, a fair comparison between the environmental effects of that conduct and its alternatives, and separate consideration of effects on public trust resources. The Commission failed to determine whether the tunnel project would extend Line 5’s operational life and thereby cause additional environmental harm, inconsistently compared the project with alternatives addressing all of Line 5, and failed to assess harm to public trust resources.
The Court reversed the Court of Appeals, vacated the Commission’s order approving the project, and remanded to the Commission for further proceedings. It did not hold that the project must be rejected.
Key Takeaways
- Judicial review of an agency’s application of the Michigan Environmental Protection Act is de novo.
- Environmental review extends to harms factually and proximately caused by proposed conduct, including harms from an extended operational lifespan when causation is established.
- An agency must compare the environmental effects of a proposal and its alternatives on a consistent basis and separately assess effects on public trust resources.
Why It Matters
The decision requires Michigan agencies and reviewing courts to conduct an independent, causation-based environmental analysis rather than confining review mechanically to the physical footprint of a proposed project. For infrastructure replacements, the inquiry may include downstream or lifespan-related harms when the project is their factual and proximate cause.
The ruling also confirms that the Michigan Environmental Protection Act protects the public trust in Great Lakes waters and submerged lands, including public uses such as fishing, hunting, and navigation. Enbridge’s approval is vacated, but the Commission may reconsider the project under the standards announced by the Court.