Four Michigan tribes are demanding state regulators open a contested case to block two key permits advancing Enbridge's Line 5 tunnel under the Straits of Mackinac, warning the approvals flout state law and put treaty-protected Great Lakes resources at risk.
The move comes one day after Gov. Gretchen Whitmer and the state's environmental director said the state must reassess permits issued in July by the Michigan Department of Environment, Great Lakes and Energy, or EGLE.
This marked yet another sharp reversal for Whitmer, who faced intense criticism from Great Lakes groups and tribes after her administration reissued wetlands and bottomlands permits for the controversial tunnel project.
However, Whitmer and the state's environmental director said a July 31 Michigan Supreme Court ruling − which found regulators with the state's Public Service commission conducted an overly narrow review and must complete a broader analysis − allows the state to reassess the permits issued by EGLE.
The original wetlands permits were issued by EGLE in 2021, but Enbridge let those expire earlier this year, then reapplied with additional wetlands‑survey data. The agency approved the application after a 16-month review.
More: Whitmer backtracks on Line 5 tunnel permits amid Great Lakes concerns
The Bay Mills Indian Community, Little Traverse Bay Band of Odawa Indians, and Sault Ste. Marie Tribe of Chippewa Indians are included in the petition. The Grand Traverse Band of Ottawa and Chippewa Indians is filing a separate one.
Bay Mills President Whitney Gravelle said it's time for Michigan to right this wrong.
"The proposed tunnel is a trap designed to keep Line 5 operating throughout Michigan for generations to come," Gravelle said in a statement. "Tribal Nations have treaty-reserved rights and a sovereign responsibility to protect the Great Lakes, and those rights cannot be ignored to preserve the interests of a foreign oil company."
The proposed tunnel through the Straits of Mackinac has long been opposed by tribes and environmental groups, as the Straits are considered the worst place in the Great Lakes for an oil spill.
On Sept. 8, around 1,000 people from all 12 Anishinaabe tribes in Michigan walked across the bridge to demonstrate opposition their opposition to Line 5.
Tribes have a heightened awareness of the risks after the recent Line 5 spill in Wisconsin's Iron County, which officials say is the largest spill in Wisconsin history.
In August, a runaway truck struck Enbridge's Line 5 at a valve site, triggering a natural-gas-liquids spill. The company. Enbridge estimates about 1.3 million gallons of mostly propane and butane vaporized into the air, with additional liquid contained on site. No injuries were reported.
The state has asked Enbridge to halt work on the reroute project around tribal land until the incident is investigated.
More: Concerns rise over Line 5 after natural gas spill, multiple frac outs
The Line 5 tunnel project has been fraught with permitting issues at the state and federal levels.
In April 2025, the project was fast-tracked as part of President Donald Trump's push to expand U.S. oil and gas development.
But before the Army Corps released its draft environmental review, several Great Lakes tribes withdrew as cooperating agencies, saying the process moved too fast and failed to protect treaty rights.
In August, the U.S. Army Corps of Engineers issued its record of decision, granting Enbridge the project's only required federal permit.
A Journal Sentinel investigation published last year reinforced those concerns, showing how Enbridge sidelined tribal voices and raising questions about Army Corps review. For instance, after bones uncovered in 2022 were deemed likely Indigenous remains, Enbridge contractors and the Army Corps did not notify the Bay Mills Indian Community, despite a plan requiring work to stop and tribes to be informed.
It also revealed how a land swap with Emmet County may have allowed Enbridge to avoid a fuller historic review of property with tribal cultural significance.
Caitlin Looby covers the Great Lakes and the environment for the Milwaukee Journal Sentinel. Contact: [email protected]. Follow her on X @caitlooby.
Caitlin is an Outrider Fellow and also receives support from the Brico Fund, Fund for Lake Michigan, Barbara K. Frank, and individual contributions to the Journal Sentinel Community-Funded Journalism Project. Journal Sentinel editors maintain full editorial control over all content. To support this work, visit jsonline.com/support. Checks can be addressed to Local Media Foundation (memo: "JS Community Journalism") and mailed to P.O. Box 85015, Chicago, IL 60689.
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This article originally appeared on Milwaukee Journal Sentinel: Michigan tribes demand state regulators block key Line 5 tunnel permits