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Michigan Supreme Court Nixes Enbridge Line 5 Tunnel Permit

8/1/2026

Summary

Michigan Court Overturns

Michigan Supreme Court overturned Enbridge Energy’s permit for a four-mile Line 5 tunnel under the Straits of Mackinac.
The court said the Michigan Public Service Commission violated the Michigan Environmental Protection Act and public trust doctrine in its 2023 permit approval, remanding the decision.
The Bay Mills Indian Community and three other Michigan tribes, represented by Earthjustice and the Native American Rights Fund, sued over the permit.

Summary

Enbridge Pushes Tunnel

Enbridge is pursuing a $500 million tunnel project slated for 2024.
The tunnel would carry Line 5’s 540,000 barrels daily and faces a 1-in-60 rupture risk according to a 2017 report.
Enbridge holds a permit, awaits U.S. Army Corps of Engineers approval, and Canada has filed treaty-based court cases to block Michigan’s shutdown effort.
Critics warn the tunnel would create noise, disturb burial sites, wetlands and species, and lock in fossil-fuel use.

History

Historical Context

The 1972 Great Lakes Water Quality Agreement, built on the 1909 Boundary Waters Treaty and the International Joint Commission, began binational efforts to curb industrial pollution in the lakes. Decades of reduced phosphorus loads and cleanup programs set a legal precedent that the Michigan Supreme Court invoked in 2024 to overturn Enbridge’s Line 5 tunnel permit, following challenges by the Bay Mills Indian Community and Earthjustice.

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Michigan Court Overturns

Michigan Supreme Court overturned Enbridge Energy’s permit for a four-mile Line 5 tunnel under the Straits of Mackinac.
The court said the Michigan Public Service Commission violated the Michigan Environmental Protection Act and public trust doctrine in its 2023 permit approval, remanding the decision.
The Bay Mills Indian Community and three other Michigan tribes, represented by Earthjustice and the Native American Rights Fund, sued over the permit.

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