Michigan Supreme Court sends Enbridge Line 5 tunnel permit back to regulators

The Michigan Supreme Court issued a 6‑1 decision ordering state regulators to revisit the permit for Enbridge Inc.'s Line 5 tunnel project. The court found the Michigan Public Service Commission had failed to assess whether the tunnel would extend the 73‑year‑old pipeline’s operation and the associated environmental risks to the Great Lakes. The ruling requires a new review of the tunnel that would bury a four‑mile stretch of Line 5 beneath the lakebed where Lake Michigan meets Lake Huron.

Enbridge, which announced the tunnel plan in 2018 with a $500 million budget and a four‑year construction timeline, said the setback was disappointing but maintained the project would improve environmental protection while preserving energy reliability. Local officials, including Sarnia Mayor Mike Bradley, warned the decision could deter investment in the region and highlighted the Canadian‑led Northern Shield pipeline as an alternative route. Indigenous leaders, such as Bay Mills Indian Community President Whitney Gravelle, welcomed the court’s willingness to reconsider the project.