Supreme Court to decide whether shutting down Michigan pipeline is a state or federal fight

Key Points

• The U.S. Supreme Court has agreed to resolve whether Michigan’s challenge to Line 5 falls under state or federal jurisdiction.
• Michigan AG Dana Nessel sued in June 2019 under the public trust doctrine to void the easement for the 4.5-mile pipeline segment beneath the Straits of Mackinac.
• Enbridge’s attempt to transfer the case to federal court was sent back by a 6th Circuit panel for missing a 30-day removal deadline, though the company argues exceptions apply.
• Line 5—operational since 1953—has known coating gaps and suffered anchor damage, prompting both spill concerns and Enbridge’s plan to encase the straits segment in a protective tunnel.

MADISON, Wis. (AP) — The U.S. Supreme Court announced Monday it will review whether Michigan Attorney General Dana Nessel's lawsuit seeking to shut down a section of an aging pipeline beneath a Great Lakes channel belongs in state court.

Nessel sued in state court in June 2019 seeking to void the easement that allows the Enbridge energy company to operate a 4.5-mile (6.4-kilometer) section of pipeline under the Straits of Mackinac, which link Lake Michigan and Lake Huron.

She won a restraining order shutting down the pipeline from Ingham County Judge James Jamo in June 2020, although Enbridge was allowed to continue operations after meeting safety requirements.

The company moved the lawsuit into federal court in 2021, arguing it affects U.S. and Canadian trade. But a three-judge panel from the 6th U.S. Circuit Court of Appeals sent the case back to Jamo in June 2024, finding that Enbridge missed a 30-day deadline to change jurisdictions.

On Monday, the Supreme Court did not explain its rationale for taking up the matter.

Enbridge officials said in a statement that they were encouraged by the Supreme Court's choice, noting that exceptions to the 30-day deadline exist.

Nessel spokesperson Kimberly Bush said the lawsuit belongs in a Michigan court. The attorney general's lawyers have argued that the case invokes the public trust doctrine, a concept in state law holding that natural resources belong to the public.

The pipeline at issue, Line 5, has moved crude oil and natural gas liquids between Superior, Wisconsin, and Sarnia, Ontario, since 1953. Concerns over the section beneath the straits rupturing and causing a catastrophic spill have been growing since 2017, when Enbridge engineers revealed they had known about gaps in the section’s protective coating since 2014. A boat anchor damaged the section in 2018, intensifying fears of a spill.

The Michigan Department of Natural Resources under Democratic Gov. Gretchen Whitmer revoked the straits easement for Line 5 in 2020. Enbridge has filed a separate federal lawsuit challenging the revocation.

The company is seeking permits to encase the section of pipeline beneath the straits in a protective tunnel. The Michigan Public Service Commission granted the relevant permits in 2023, but Enbridge still needs approval from from the U.S. Army Corps of Engineers and the Michigan Department of Environment, Great Lakes and Energy.

The pipeline is at the center of a legal dispute in Wisconsin as well. A federal judge in Madison last summer gave Enbridge three years to shut down part of Line 5 that runs across the Bad River Band of Lake Superior’s reservation. The company has proposed rerouting the pipeline around the reservation and has appealed the shutdown order to the 7th U.S. Circuit Court of Appeals.