Michigan state regulatory agencies approved major permits on Wednesday for the construction of a tunnel designed to replace a section of the Line 5 pipeline that runs through the Straits of Mackinac. The Department of Environment, Great Lakes, and Energy issued a construction permit for the project after what officials described as a comprehensive review, determining that preventing a potential oil spill in the Great Lakes outweighed other public interests. The Department of Natural Resources also granted a permit while acknowledging that construction would cause adverse impacts to rare plants and animals in the region.
The Line 5 pipeline has operated for more than 73 years, transporting crude oil and natural gas liquids across a 645-mile route from Superior, Wisconsin, to Sarnia, Ontario. Enbridge Energy, the pipeline operator, characterizes the tunnel project as essential to protecting the Great Lakes and maintaining reliable energy supply to Michigan and the broader region. An Enbridge spokesperson called the permits an important step forward and stated the company is reviewing them to assess impacts on tunnel construction.
Opposition groups mounted immediate criticism of the permit approvals. Environmental advocates argued that the project is unnecessary and will cause irreversible damage to wetlands and forests. Tribal nations, particularly the Bay Mills Indian Community whose treaty lands the tunnel would cross, expressed deep concerns about the disturbance of ancestral remains and cultural resources. State law requires Enbridge to implement mitigation measures such as seed collection for restoration and seasonal tree clearing to protect wildlife.
The permits represent progress toward project completion but do not conclude the approval process. Enbridge still requires additional federal and state permits, and the Michigan Supreme Court is expected to issue a decision before the end of summer regarding a previously issued state permit that has been challenged in court. A federal permit from the U.S. Army Corps of Engineers is considered likely given the Trump administration’s declaration of a national energy emergency last year that expedited review for energy infrastructure projects. The Bay Mills Indian Community is exploring legal options, including a contested case hearing, to challenge the permits issued this week.