We oppose Enbridge’s dangerous proposal to build a 21-foot diameter tunnel beneath the Mackinac Straits bottomlands to house the oil pipeline for several reasons. One, tunnel permitting and construction timeline, if ever approved, would run nearly a decade, and during that entire time, the risk of a Straits oil spill grows. The Michigan Public Service Commission and the U.S. Army Corps of Engineers are considering the tunnel’s likely environmental risks and impacts, including to the climate and the Great Lakes.

Experts worry that a leak within the tunnel would create a highly flammable and dangerously explosive environment due to the possible accumulation of crude oil and natural gas liquids in an enclosed space. Finally, the pipeline tunnel also involves approving a massive oil infrastructure project at the very moment when climate scientists and economic experts insist the world must take rapid action—including the shutdown of Line 5—to decrease the use of fossil fuels for the sake of future generations and life as we know it. Bottom line, the people of Michigan bear the risk of this pipeline. It threatens our prosperity, our precious waters and lands, our way of life. Meanwhile, Enbridge and Canada reap essentially all of the profits and benefits.

The answer is both. While the federal government regulates energy pipeline safety, Michigan oversees the 1953 easement it granted to Enbridge for Line 5’s conditional use of the Mackinac Straits where the pipeline crosses—exposed above the bottomlands—in the turbulent open waters. Michigan, under the public trust doctrine, also governs allowable activities in its Great Lakes waters and forbids actions that diminish the value of the lakes for other users. An oil spill would destroy the water’s value for all others.

The Michigan Public Service Commission (MPSC) also is considering whether to grant Enbridge authority to replace and redirect Line 5 through a proposed tunnel underneath the Straits of Mackinac bottomlands. The MPSC considers demonstrated public need, safety and engineering standards, reasonableness, harm to the climate and environment, and feasible and prudent alternatives to the proposal. The U.S. Army Corps of Engineers (USACE), Detroit District, is reviewing Enbridge’s tunnel application under the Rivers and Harbors Act and the Clean Water Act because of proposed dredging, discharge, and construction in the Straits. USACE is preparing an Environmental Impact Statement (EIS) under the National Environmental Policy Act to reach a final decision expected in early 2026 on the permit application. The corps is also preparing an Ethnographic/Traditional Cultural Landscape Study as part of the EIS, which is required under the National Historic Preservation Act.

Michigan Attorney General Dana Nessel filed a lawsuit in 2019 in Ingham County Circuit Court to revoke Line 5’s state-granted easement to use the Straits of Mackinac. She alledged that Enbridge’s continued operation of Line 5 in the Straits is a common law public nuisance and violates the public trust doctrine and the Michigan Environmental Protection Act. Gov. Gretchen Whitmer, in November 2020, ordered Enbridge to shut down Line 5 under the public trust doctrine and revoked and terminated the Line 5 easement due to repeated violations.

The State of Michigan and Enbridge continue to battle over whether the state’s legal efforts to shut down Line 5 belong in state or federal court, which the Sixth Circuit of the U.S. Court of Appeals is considering. A federal trial court in Wisconsin in June 2023 found Line 5 to be a public nuisance and in trespass on the Bad River Band reservation and ordered the pipeline shut down within three years if not removed and rerouted before that time; Enbridge has appealed.

Nearly all of Line 5’s oil and natural gas liquids, including propane, are destined for refineries in Sarnia, Ontario. There is only one oil refinery in Michigan, in Detroit, and it is designed for heavy crude, which is not allowed to be transported in Line 5. While Line 5 does carry a sizable portion of Michigan’s propane supply, alternative means of transportation—like truck and rail—are used all over America to transport propane. Trucks already carry propane throughout Michigan. Gov. Whitmer formed an Upper Peninsula Energy Task Force to identify energy supply options, including for propane, in the event that Line 5 is shut down. The task force found that the propane-delivery system can adjust with smart planning. Shutting down Line 5 would add just 5 cents to the cost of a gallon of propane, according to a 2018 study by London Economics International.

Enbridge’s own expert in 2022 testified in a Wisconsin court that shutting down Line 5 would result in only a half-cent per gallon increase in the gasoline price in Michigan and Wisconsin. That’s the cost to avert an environmental disaster in the Great Lakes. PLG Consulting, an energy industry group, found in an October 2023 report that energy markets will adapt without supply shortages or price spikes in the event of a planned and orderly shutdown of Enbridge’s Line 5 oil pipeline. Contingency plans have been developed for at least the past six years by key refiners and other businesses whose supply chains may be altered if Line 5 is shut down.

For more than a decade, Groundwork has been central to focusing attention on the environmental and economic risk posed by Line 5, as well as on secure energy supply alternatives. We organized the first big protest gathering at the Mackinac Straits in 2013, with international environmental leader Bill McKibben. We have remained deeply involved ever since, by:

• Helping form three influential nonprofit advocacy groups—Oil & Water Don’t Mix, Great Lakes Business Network, and Friends of Mackinac Bridge,
• Authoring a widely quoted whitepaper, “Canadian Profits, Michigan Risk,”
• Organizing opposition in the Upper Peninsula and throughout Michigan,
• Meeting with state and federal lawmakers and other decision-makers.

Individuals, families, community groups, businesses, local and tribal governments, and others can get involved in the effort to shut down Line 5 by taking the actions listed below and sharing information with your network of friends and family members.