Michigan Approves Enbridge Tunnel to Replace Line 5 Pipeline

The Michigan Department of Environment, Great Lakes, and Energy (EGLE) and the Michigan Department of Natural Resources (DNR) issued critical construction permits on July 15, 2026, for Enbridge Energy to build a four-mile concrete-lined tunnel beneath the Straits of Mackinac. The project aims to replace 73-year-old dual pipelines on the lakebed to eliminate an unacceptable oil spill risk and ensure the flow of energy to the region.

State regulators concluded that the public and private need for the tunnel outweighed other interest criteria, though they acknowledged the project would cause significant impacts. These include the destruction of Native American burial grounds and damage to wetlands and rare species, such as the dwarf lake iris and Houghton's goldenrod. The DNR mandated specific mitigation efforts to protect these species and bat habitats.

The decision triggered immediate condemnation from Tribal leaders and environmental activists. The Bay Mills Indian Community and Sault Tribe criticized the disregard for Tribal sovereignty and the disruption of sacred sites, with the Bay Mills Indian Community vowing to sue. U.S. Representative Rashida Tlaib and the Oil & Water Don't Mix coalition accused Governor Gretchen Whitmer of betraying campaign promises to shut down Line 5.

While these permits clear the way for a final decision by the U.S. Army Corps of Engineers, the project remains mired in legal uncertainty. Other permits are currently being challenged in state and federal courts, and estimated costs have climbed from $500 million in 2018 to at least $750 million, with some estimates suggesting billions more by 2030.