Michigan court orders new review of Enbridge Line 5 tunnel permit

73-year-old pipeline runs 4 miles along Straits of Mackinac floor

The Michigan Public Service Commission granted a permit to build the tunnel in 2023, according to the Associated Press. Four Michigan tribal nations and several environmental groups sued over the approval, the AP reported.

The 6-1 Michigan Supreme Court ruling sends the matter back to the commission for further reconsideration, further clouding the future of the pipeline, the AP reported. The pipeline, owned by Canadian energy transportation company Enbridge, carries petroleum from Superior, Wisconsin, to Sarnia, Ontario.

The part of the pipeline at issue, called Line 5, runs for 4 miles (6 kilometers) along the bottom of the Straits of Mackinac where Lake Huron and Lake Michigan meet, the AP reported.

Whitmer, the state’s governor, wants the pipeline moved away from the waterway entirely, according to the AP. She has said a spill would be catastrophic to the Great Lakes and surrounding area.

Enbridge wants to bury the pipeline in a tunnel under the straits, the AP reported.