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Enbridge Line 5 tunnel project in Michigan delayed another 1.5 years

Mackinac Bridge
Enbridge Energy’s Line 5 transports petroleum products through Michigan via a dual-span pipeline at the bottom of the Straits of Mackinac. (Photo by Lester Graham, Michigan Radio)
  • Permitting delays have tacked on another year-and-a-half to the planned Line 5 tunnel project under the Straits of Mackinac 
  • Assuming the project gets needed permits, construction won’t begin until 2026 at earliest
  • The tunnel was supposed to be completed in 2024

U.S. federal regulators say they need more time to scrutinize the environmental impacts of the proposed Line 5 tunnel, adding another year-and-a-half delay to a project that Canadian energy company Enbridge Energy originally vowed to complete next year.

Instead, the yearslong tunnel construction project won’t begin until at least 2026, if it begins at all.

Enbridge is still awaiting key state and U.S. permits needed to build the tunnel.


The U.S. Army Corps of Engineers Detroit District, from which Enbridge needs two permits, announced Thursday that it is extending its decision timeline after receiving more than 17,000 public comments regarding the proposed tunnel.

“We greatly appreciate the meaningful input received throughout scoping and will use this information to shape studies and continuing consultations throughout development of our draft environmental impact statement” Detroit District Commander Lt. Col. Brett Boyle said in a statement.

The delay adds new tension as environmentalists and Michigan Attorney General Dana Nessel spar with Enbridge over its existing 70-year-old dual-span petroleum pipeline at the bottom of the straits.

Line 5 opponents contend that the existing pipeline should be shut down immediately, citing its age and the threat an oil spill would pose to the straits. Enbridge, on the other hand, argues Line 5 can operate safely along the sandy bottom of the straits until it is eventually relocated into a tunnel bored deep beneath the lakebed.

The tunnel plan emerged in the final days of former Gov. Rick Snyder’s administration, when the company and Snyder agreed to the tunnel to resolve public concerns that Line 5 could rupture in the Great Lakes. At the time, the company estimated it would finish the tunnel project by 2024.

In an emailed statement Thursday, Enbridge spokesperson Ryan Duffy expressed disappointment about the latest delay.

“While we are supportive of a thorough, comprehensive and carefully considered permitting process that ensures adequate opportunity for review and comment, we are disappointed with the extended timeline for a project of this scope,” Duffy said.

Environmentalists said the Army Corps decision was not surprising. They have long accused Enbridge of purposely underestimating its timeline to create a false perception that Line 5 would soon be out of the water.

“It’s another unfortunate case of Enbridge lying to the Michigan public and getting away with it,” said Sean McBrearty, coordinator of the anti-Line 5 coalition Oil & Water Don’t Mix. “From the beginning, we’ve said this is an unrealistic timeline, and building an oil tunnel through the Great Lakes is an unrealistic proposal.”

While federal regulators consider the tunnel plan, Enbridge continues to ship petroleum products through the existing lakebottom pipes, in defiance of a shutdown order from Gov. Gretchen Whitmer.

Nessel, meanwhile, has been pursuing a lawsuit since 2019 that aims to shut down the pipelines. A judge has yet to issue a final decision on whether the case should be heard in federal court (which Enbridge prefers) or state court (which Nessel prefers).

With no clear pathway to quickly remove Line 5 from the water, McBrearty, of Oil & Water Don’t Mix, urged the Biden administration to step in. The administration could intervene in the court case on Michigan’s behalf, or simply revoke permits for Line 5, he said. 

But the administration, which is also under pressure from Canada to keep Line 5 flowing, has been reluctant to weigh in publicly. Biden is on a two-day visit to Canada, which begins Thursday evening and extends into Friday. It’s unclear if Line 5 is on the agenda as he meets with Canadian Prime Minister Justin Trudeau. 

Duffy said Enbridge remains committed to the tunnel project, as well as “the continued safe operation of the Line 5 crossing of the Straits, and ensuring an uninterrupted supply of reliable, affordable energy to Michigan and the region.”

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