LANSING – The Whitmer administration has approved key environmental permits for Enbridge’s proposed Great Lakes Tunnel beneath the Straits of Mackinac, marking one of the biggest regulatory victories yet for the controversial Line 5 project while setting the stage for another round of legal and political battles.
The Michigan Department of Environment, Great Lakes, and Energy (EGLE) approved wetlands protection and Great Lakes submerged lands permits for the tunnel, clearing another major hurdle for a project supporters say will better protect the Great Lakes while preserving a critical energy artery serving Michigan and the surrounding region.
The decision immediately divided business leaders and environmental advocates, underscoring the decades-long debate over balancing Michigan’s energy security with protection of the world’s largest freshwater system.
Business Groups Welcome Decision
The Michigan Chamber of Commerce praised the approval, calling the tunnel a long-term investment in both environmental protection and energy reliability.
“Safe, reliable and affordable energy is foundational to Michigan’s employers, families, communities and economy,” said Jim Holcomb, president and CEO of the Michigan Chamber of Commerce. “The Great Lakes Tunnel is a major investment and commonsense solution that enhances protection of the Great Lakes while ensuring the long-term reliability of critical energy infrastructure across our state and region. We applaud the decision and look forward to seeing this important project become a reality.”
Enbridge also welcomed the decision, noting that EGLE had renewed permits originally issued in 2021.
“The Michigan Department of Environment, Great Lakes and Energy’s renewal of permits it previously granted in 2021 for the Great Lakes Tunnel Project is an important step forward for a project designed to further protect the Great Lakes while helping ensure the uninterrupted flow of energy that supports Michigan and the region,” the company said in a statement.
Enbridge said it is reviewing the permit conditions to determine whether they will affect construction plans.
The company also emphasized that Line 5 continues to operate safely under federal pipeline safety regulations while additional safeguards remain in place, including its Straits Maritime Operations Center, which monitors commercial vessel traffic around the clock to reduce the risk of an anchor strike until the tunnel is completed.
Supporters argue the project represents the safest long-term solution by relocating the existing dual pipelines from the lakebed into a concrete-lined tunnel drilled through bedrock beneath the Straits of Mackinac. They contend the project protects both the Great Lakes and the continued flow of crude oil and natural gas liquids used to produce gasoline, diesel fuel, jet fuel and propane for Michigan and neighboring states.
Environmental Groups Condemn Approval
Environmental organizations blasted the decision, arguing Michigan is committing itself to nearly a century of additional fossil fuel infrastructure despite climate concerns and the risk of an oil spill.
“Approving new 99-year fossil fuel infrastructure as people across Michigan choke on climate change-induced wildfire smoke just adds insult to injury,” said Ashley Rudzinski, climate and environment program director for the Traverse City-based Groundwork Center for Resilient Communities.
She argued the decision conflicts with Michigan’s climate goals as the state faces more extreme weather, shoreline erosion and other impacts associated with climate change.
“The Great Lakes are the largest freshwater system on the planet, and they deserve the highest level of protection—not regulatory rubber stamping,” Rudzinski said. “By approving this permit, Governor Whitmer and EGLE have placed the interests of a private foreign oil company above the long-term health of our waters, our climate and our economies.”
Groundwork Center also questioned long-term financial liability should a future spill occur and called on EGLE to halt additional project activity while legal appeals proceed.
Years of Controversy
Line 5 has transported oil and natural gas liquids through Michigan since 1953. The most controversial section consists of twin pipelines resting on the bottom of the Straits of Mackinac, where Lakes Michigan and Huron meet.
Following concerns over the aging pipelines and the possibility of a spill, Enbridge proposed constructing a tunnel beneath the Straits that would house a replacement pipeline inside reinforced concrete hundreds of feet below the lakebed.
The project has divided Michigan for years.
Supporters—including business organizations, labor unions, many Upper Peninsula officials and energy users—argue shutting down Line 5 without a replacement would threaten propane supplies, increase fuel costs and disrupt energy supplies throughout the region.
Opponents—including environmental organizations and many tribal governments—argue the safest option is to permanently decommission the pipeline and accelerate the transition to renewable energy.
More Hurdles Remain
Thursday’s approval does not authorize immediate construction.
The project still faces additional federal permitting requirements and continuing litigation in state and federal courts. Environmental organizations have already indicated they intend to challenge EGLE’s decision.
For now, however, the permit approval represents another significant victory for Enbridge after years of regulatory reviews, legal challenges and political debate.
Whether the Great Lakes Tunnel ultimately becomes reality will likely depend as much on the courtroom as the construction site.
