Key facts
- Michigan Supreme Court rejected a key permit for Enbridge's Line 5 oil pipeline.
- The court cited regulators' failure to consider environmental harm and public trust rights.
- The pipeline carries petroleum under the Straits of Mackinac, a critical waterway.
- Environmentalists and Michigan's governor have sought to move the pipeline away from the Great Lakes.
- Enbridge proposed the tunnel nearly a decade ago after a previous pipeline damage incident.
The Michigan Supreme Court has ordered state regulators to reconsider a crucial permit that allowed Enbridge's Line 5 oil pipeline to proceed with construction of a tunnel beneath the Straits of Mackinac. The 6-1 decision, issued Friday, further complicates the future of the 73-year-old pipeline, which transports petroleum between Wisconsin and Ontario.
The court found that the Michigan Public Service Commission, when granting the permit in 2023, failed to adequately consider whether the proposed tunnel project would extend the pipeline's operational life, potentially leading to greater environmental harm. The ruling also stated that the commission was inconsistent in comparing alternative transport methods for the oil, such as trucks or trains, and did not properly assess the tunnel's potential impact on public trust rights, including fishing and boating on the Great Lakes.
Environmental groups and four Michigan tribal nations had sued to block the project. Opponents argue that pumping large volumes of oil through the Great Lakes poses a catastrophic risk to the ecosystem and that the proposed tunnel construction would cause significant, long-term environmental damage. Michigan Governor Gretchen Whitmer has also been pursuing efforts since 2020 to shut down the pipeline.
Enbridge, which proposed the tunnel nearly a decade ago following an incident where a ship's anchor damaged the existing line, stated it is reviewing its legal options and expressed disappointment over the delay. The company maintains that the tunnel would enhance environmental protection and ensure critical energy reliability for the region.