Michigan Supreme Court to review Line 5 replacement plan

By Niina H. Farah, Carlos Anchondo | 09/22/2025 06:44 AM EDT

The court granted tribal nations’ request to review a state regulators’ approval of a tunnel project beneath the Straits of Mackinac.

Damage to an anchor support on the east leg of the Enbridge Line 5 pipeline.

Damage to an anchor support on the east leg of the Enbridge Line 5 pipeline is seen in this photo shot from a television screen in June 2020. Michigan Department of Environment, Great Lakes, and Energy via AP

A legal fight over state regulators’ approval of Enbridge’s contentious Line 5 tunnel project will continue before Michigan’s highest court.

The Michigan Supreme Court on Friday granted the request, led by the Bay Mills Indian Community, to review the Michigan Public Service Commission’s authorization for the project, which would shield a 30-inch-diameter pipeline within a concrete-lined tunnel that would run roughly 4 miles under the Straits of Mackinac.

The Great Lakes Tunnel project was introduced to replace a segment of dual pipelines at the bottom of the straits that critics have warned are at risk of spilling oil. But the planned tunnel has also faced strong opposition over environmental concerns about the project itself, as well as fears the tunnel would extend the lifespan of the aging Line 5 pipeline.

Advertisement

“The Commission approved this project without a true consideration of its impacts or an analysis of whether Michiganders need it, but one thing is clear: The heart of the Great Lakes is simply no place for an oil pipeline tunnel,” said Adam Ratchenski, senior associate attorney for Earthjustice, which is representing the project’s challengers, along with the Native American Rights Foundation.

GET FULL ACCESS