Michigan Supreme Court Vacates Enbridge Line 5 Pipeline Tunnel Permit

The Michigan Supreme Court ruled 6-1 to vacate a permit granted by the Michigan Public Service Commission for Enbridge Inc. to construct a tunnel under the Straits of Mackinac. The court found that the commission's 2023 review was overly narrow and violated the Michigan Environmental Protection Act by failing to assess if the project would extend the pipeline's operational life or increase environmental harm. The ruling also cited a failure to consistently evaluate transport alternatives or the impact on public trust resources, such as boating and fishing.

The decision remands the permit to the commission for further assessment, delaying a project first proposed in 2018 to reroute a 4-mile segment of the 73-year-old petroleum pipeline. While the tunnel was designed to prevent oil spills, a coalition of four tribal nations and environmental groups argued the pipeline should be shut down entirely. This legal setback follows a 2020 shutdown order from Governor Gretchen Whitmer, which Enbridge continues to defy by transporting oil into Canada.

Tribal leaders and environmental advocates celebrated the ruling as a victory for treaty rights and the protection of sacred sites. Enbridge expressed disappointment, citing the additional delay to a decade-long review process. The project still requires further state and federal approvals beyond the commission's review.