Proposed Line 5 tunnel project construction area, southern end | U.S. Army Corps of Engineers screenshot
The Michigan Department of Environment Great Lakes and Energy has opened public comment on a set of permits tied to Canadian energy company Enbridge’s plans to relocate its Line 5 pipeline into a new segment embedded beneath the Straits of Mackinac.
Line 5 stretches from Northwestern Wisconsin to Sarnia, Ontario, including a 4.5 mile stretch on the lakebed where Lake Huron and Lake Michigan meet. The pipeline transports more than 22 million gallons of crude oil and natural gas liquids through the Great Lakes daily, raising concerns amongst environmental advocates, who warn that an oil spill would carry catastrophic consequences.
Enbridge identified gaps in the pipelines protective coating in 2014, and the pipeline was later dented in three places by an anchor strike in 2018. The pipeline company later reached an agreement with the state to consolidate the dual pipelines currently operating in the Straits of Mackinac into a new segment housed in a concrete-lined tunnel and buried below the lakebed, in hopes of containing any potential oil spills.
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In order to move forward with the project, Enbridge needs approval from three agencies, the Michigan Department of Environment, Great Lakes and Energy, the Michigan Public Service Commission and the U.S. Army Corps of Engineers.
While EGLE and the Public Service Commission have both approved permits for the project, a 2024 settlement between Enbridge, EGLE and the Bay Mills Indian Community requires the company to redo its water resources permit using the results of new wetlands surveys.
EGLE opened public comment on the company’s revamped wetlands protection and Great Lakes Submerged Lands permits on July 17, with the comment period to remain open through Aug. 29, 2025.
The department will also host two meetings throughout the public notice period: an information session on Aug. 12 in a Q&A format regarding the application and EGLE’s review process and a formal public hearing on Aug. 19, where comments will be taken for the record. Additional comments can be submitted online.
During this period EGLE said it would review the application and information provided by the applicant, collect and consider public comments, continue tribal consultations and continue coordinating with other agencies and partners.
This map shows the proposed tunnel and the existing dual pipelines crossing the Straits of Mackinac. | Screenshot from the MPSC Line 5 Issue Brief
During the public notice period, EGLE said it’s common for the department to request applicants to consider additional modifications to the project and provide additional information in response to the ongoing review and in coordination with other state agencies and parties.
“Enbridge’s commitment to safeguarding the Great Lakes, natural resources, and communities continues to drive our work behind building the Great Lakes Tunnel, and locating a new, replacement section of the Line 5 pipeline inside the protection of the tunnel, deep under the lakebed,” Enbridge Spokesperson Ryan Duffy said in an email.
“We support and welcome the public comment process now underway. Public and stakeholder input is essential to the process and we look forward to hearing feedback and answering questions,” he said.
As EGLE opens public comment on the permits, members of the National Wildlife Federation are demanding the department conduct a full review of Enbridge’s proposed drilling area as required by the Great Lakes Submerged Lands Act, pointing to concerns of tunnel collapse, explosion and pollution during the construction of the Line 5 tunnel.
“The Great Lakes Submerged Lands Act is in place to safeguard the Great Lakes and our natural resources from unnecessary projects that cause harm,” Beth Wallace, the federation’s Great Lakes climate and energy director said in a statement. “Any attempt to shortcut or narrow their review will only benefit the interest of big oil, could open a wide door for other extractive industries, and would undermine the legal standards meant to protect our public waters.”
An EGLE spokesperson did not respond to a request for comment.