Enbridge is a step closer to building a new oil tunnel beneath the Straits of Mackinac for its Line 5 after the state of Michigan approved permits for the project last week.

Line 5 runs 645 miles from Superior, Wisconsin, to Sarnia, Ontario, carrying crude and natural gas liquids. Most of it transits Michigan to reach Canada.

Enbridge and the state say a concrete tunnel would get the 73-year-old pipeline out of open water, where a rupture could spill into the Straits of Mackinac.

But the permit concedes some of what is at stake. Historic and cultural resources will likely be destroyed — the remains of tribal ancestors among them. Enbridge has to file a plan to lessen the damage. Environmental activists and Michigan tribal communities say that is not enough.

In a statement to The Metro, Enbridge said it respects the cultural and historic significance of the Straits and is committed to protecting cultural resources. The company said its surveys were directed by the U.S. Army Corps of Engineers, that tribal representatives have been consulting parties in that process, and that more cultural survey work is scheduled for 2027.

The Straits are where the Bay Mills Indian creation story begins. They are also among the most productive fishing grounds for tribes exercising rights under an 1836 treaty.

Whitney Gravelle is a federal Indian law attorney and president of the Bay Mills Indian Community, which has vowed to fight back. She joined Robyn Vincent on The Metro to discuss why she calls the state’s decision a betrayal.

This story has been updated with a statement from Enbridge. -Ed

Enbridge is a financial supporter of WDET. The WDET newsroom observes a clear boundary between funders and editorial content, and does not serve the agendas of financial supporters.

Hear the full conversation using the media player above.

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