Michigan Supreme Court Haults Mackinac Strait Pipeline Replacement

• The Michigan Supreme Court vacated an order approving the replacement of Line 5 pipelines under the Mackinac Strait on July 31, 2026.
• State regulators must now assess the project's potential environmental harms and compare them with alternative proposals.
• The court emphasized that state regulators must consider whether the replacement project poses a risk of pollution or harm to public trust resources.

The state must also consider whether the replacement project “may pollute, impair or destroy public trust resources.”

The Michigan Supreme Court has dealt a significant blow to Enbridge's plans to replace Line 5 pipelines under the Mackinac Strait. In a recent ruling on July 31, 2026, the court vacated an order approving the replacement project and directed state regulators to reassess its environmental implications. This development marks a major shift in the regulatory landscape for pipeline projects in Michigan.

The court's decision is rooted in Michigan's constitution, which grants the state authority to regulate public trust resources. The ruling emphasizes that state regulators must consider whether the replacement project poses a risk of pollution or harm to these resources. This precedent-setting decision has significant implications for similar pipeline projects across the US, where state regulators may now be more inclined to scrutinize environmental concerns and compare them with alternative proposals.

The Michigan Supreme Court's ruling sets a crucial precedent for state regulators nationwide. By mandating an assessment of potential environmental harms and comparison with alternative proposals, the court has effectively given states more teeth to regulate pipeline projects that may pose risks to public trust resources. This development is particularly significant in light of growing concerns about the environmental impact of Line 5 pipelines, which transport crude oil and natural gas liquids under the Mackinac Strait.

Lawyers should watch for the implications of this ruling on similar pipeline projects in the US, as it sets a precedent for state regulators to assess potential environmental harms and compare them with alternative proposals.

Source: Original reporting via [Source]