Michigan’s environmental agency has signed off on Enbridge’s Great Lakes Tunnel project – a first-of-its-kind, massive tunnel that will carry its Line 5 pipeline underneath the Straits of Mackinac.
The move marks a significant shift from Gov. Gretchen Whitmer’s earlier efforts to shut down the Line 5 pipeline and limit spill risks in the Straits, which separate Lakes Michigan and Huron.
The Michigan Department of Environment, Great Lakes, and Energy, or EGLE, approved the permits on July 15. The tunnel still needs a federal permit from the U.S. Army Corps of Engineers, which fast-tracked its review under the Trump administration. Enbridge is also awaiting final decisions from Michigan’s Department of Natural Resources and from EGLE on a separate wastewater discharge permit.
“This betrayal puts our Great Lakes at risk for the sake of a pipeline that serves foreign oil interests and would enable a tunnel project that the U.S. Army Corps of Engineers admits will cause permanent and irreversible cultural and environmental damage,” said Beth Wallace, climate and energy director for the National Wildlife Federation.
Over the years in the Straits of Mackinac, ship anchors have hit the pipeline, sections have needed extra support, and protective coating has been damaged or worn away. Enbridge says the proposed Great Lakes Tunnel, housing Line 5 through the 4½‑mile stretch between Lakes Michigan and Huron, would nearly eliminate the risk of a pipeline incident.
The tunnel will be bored into rock 60 to 250 feet under the lakebed, using a tunnel boring machine that would progress 40 feet per day on average during construction. It will be constructed from the south side of the Straits to the northern shores.
Enbridge Spokesperson Juli Kellner said late Wednesday afternoon the state approval “is an important step forward for a project designed to further protect the Great Lakes while helping ensure the uninterrupted flow of energy that supports Michigan and the region.”
The tunnel project has been contentious from the start, including Whitmer’s 2020 move to revoke Enbridge’s easement soon after taking office. It has since been tangled in ongoing legal fights in both state and federal courts.
In July 2025, a Journal Sentinel investigation found that Enbridge sidelined tribal voices in the Line 5 tunnel process. It also showed how federal oversight can be used to bypass protections for Indigenous lands, including through a land swap with Emmet County in Michigan that appears to have helped the company avoid a fuller historic review even though part of the property held tribal cultural significance.
Before the Army Corps even released its draft environmental review, several Great Lakes tribes withdrew as cooperating agencies, saying the federal process was being fast-tracked and did not honor the government’s obligation to protect treaty rights
Caitlin Looby covers the Great Lakes and the environment for the Milwaukee Journal Sentinel. Contact: clooby@gannett.com. Follow her on social media @caitlooby.
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This article originally appeared on Milwaukee Journal Sentinel: Michigan signs off on Canadian oil giant’s Line 5 pipeline project
Reporting by Caitlin Looby, Milwaukee Journal Sentinel / Milwaukee Journal Sentinel
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By Caitlin Looby, Milwaukee Journal Sentinel | USA TODAY Network
