Army Corps of Engineers Permits Enbridge Line 5 Tunnel

The United States Army Corps of Engineers issued a permit on August 12, 2026, authorizing Enbridge Energy LP to construct a four-mile tunnel beneath the lake bed in the Straits of Mackinac. The project aims to house a segment of the Line 5 pipeline, replacing two existing pipelines that currently run along the lake bed.

Enbridge Energy describes the tunnel as a preventative safety measure intended to eliminate the risk of oil and natural gas liquid spills resulting from pipeline ruptures or anchor strikes. The company argues that moving the infrastructure underground will protect the surrounding environment from potential leaks.

Tribal nations and environmental advocates oppose the construction, citing potential damage to wetlands and the destruction of cultural and archaeological sites. Opponents further claim that a recent decision by the Michigan Supreme Court legally bars the construction of the tunnel, setting the stage for a legal conflict over the project's viability.