July 10, 2026
Lansing, MI. – Today, the Michigan Supreme Court handed down a decision that sided with environmental and Tribal groups in their combined cases that challenged Enbridge Energy’s efforts to bore a tunnel beneath the Straits of Mackinac to house its Line 5 oil pipeline.
The Supreme Court overturned a lower court decision that upheld the Michigan Public Service Commission’s (MPSC) approval for the tunnel. The decision reverts the case to the MPSC for a more thorough review of the tunnel’s impact on Michiganders and the environment, as required by the landmark Michigan Environmental Protection Act (MEPA).
The Supreme Court concluded that the lower court applied the incorrect legal standard, that the MPSC’s review of the environmental harms from the tunnel was improperly narrow, and that the MPSC failed to consider the tunnel’s impact on public trust resources. The Court concluded that the MPSC must consider whether, as plaintiffs allege, the Line 5 tunnel would extend the risks of pumping oil across the Great Lakes and throughout Michigan for another 99 years.
The Environmental Law & Policy Center (ELPC) and Michigan Climate Action Network (MiCAN) argued alongside the Bay Mills Indian Community, Little Traverse Bay Bands of Odawa Indians, Grand Traverse Band of Ottawa and Chippewa Indians, and the Nottawaseppi Huron Band of the Potawatomi, represented by Earthjustice and the Native American Rights Fund (NARF). Flow Water Advocates argued that the MPSC should have rejected the tunnel under common-law public trust doctrine.
Denise Keele, PhD, Executive Director of MiCAN, said:
“This inspiring decision accepts the undeniable reality of the need to consider the likely impacts from increased greenhouse gas emissions, and all the risks Michiganders will bear if we continue to allow a foreign corporation to profit from a shortcut through the Great Lakes. We now have a chance to stop new fossil fuel infrastructure and avoid nearly 30 million tons of carbon emissions annually. We are committed to supporting the process moving forward and are grateful for the opportunity to show that the tunnel is not a safer option, especially as Michigan leads the way toward a clean energy future.” Keele continued to remark on co-plaintiffs outcome “Additionally, this decision not only acknowledges climate change, but the voices of a sovereign tribal nation, the Bay Mills Indian Community, whose way of life, sacred sites, and ancestors will now have a chance to be protected. We stand as allies with our tribal partners as we live to fight another day and stop this risky and unnecessary tunnel.”
David Scott, Senior Attorney at ELPC and MiCAN’s pro bono attorneys, said:
“Today the Michigan Supreme Court sent a clear message that the Line 5 tunnel has not yet received the rigorous environmental review that Michigan law requires. The Court’s decision stands as an important reminder that the Michigan Environmental Protection Act means what it says: that regulators and courts must determine all of the tunnel’s polluting and impairing effects on Michigan’s air, water, and natural resources and thoroughly analyze the alternatives to this project. We look forward to reengaging before the Michigan Public Service Commission to pursue a full environmental review and alternatives analysis consistent with the Michigan Supreme Court’s directions.”
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