U.S. Army Corps approves Enbridge pipeline tunnel project

The U.S. Army Corps of Engineers has approved a proposal by Canadian company Enbridge to construct a four-mile tunnel beneath the Straits of Mackinac. The tunnel is intended to house the Line 5 oil pipeline, which serves eastern Canada. This federal approval followed recent permits granted by Michigan’s Department of Environment, Great Lakes, and Energy (EGLE) under Governor Gretchen Whitmer.

Despite the federal decision, the project faces significant legal hurdles. The Michigan Supreme Court recently struck down a permit from the Michigan Public Service Commission (MPSC), ordering the agency to conduct a new, comprehensive analysis of environmental and public trust impacts. Consequently, Enbridge cannot proceed with construction without this state-level permit.

Critics, including tribal advocates and environmental groups, argue the Army Corps fast-tracked the decision using a January 2025 presidential executive order regarding a “national energy emergency.” Opponents claim the project threatens the Great Lakes, risks permanent loss of wetlands and wildlife habitats, and desecrates sacred Anishinaabe tribal spaces. They also note that the proposed method of running a hazardous liquids pipeline through an underground tunnel has not been attempted elsewhere.