LANSING  — A federal judge has halted Michigan Gov. Gretchen Whitmer’s long-running effort to force the shutdown of the Enbridge Line 5 oil pipeline, ruling that federal law, not state authority, controls interstate pipeline safety.

U.S. District Judge Robert J. Jonker ruled Dec. 17 that the Pipeline Safety Act of 1992 bars Michigan from imposing its own safety standards to take a 540,000-barrel-a-day pipeline offline, rejecting a key argument in Whitmer’s case. The judge said the state’s safety concerns — though legitimate — cannot override federal jurisdiction, and found that Michigan’s attempt to enforce its own regulations was “exactly the kind of state-imposed safety standards” Congress intended to preempt.

The ruling keeps Enbridge’s Line 5 operating where it crosses the sensitive Straits of Mackinac on the lakebed between Lakes Michigan and Huron — a section Whitmer has long targeted over environmental and spill-risk concerns.

Whitmer initially ordered regulators in 2020 to revoke the pipeline’s easement and halt operations, saying the aging infrastructure posed a threat to the Great Lakes. The governor’s legal team also argued the 1953 easement allowing operation was void under the public trust doctrine, which gives states authority to protect natural resources. But Judge Jonker rejected those claims, saying Michigan lacked the authority to shut down an interstate pipeline and that doing so would infringe on federal safety oversight.

“The state may be right in its policy judgments,” Jonker wrote, “but it was not their call to make.”

A spokesperson for Michigan Attorney General Dana Nessel called the ruling “legally flawed” and an affront to the state’s sovereign interests in submerged lands. Litigation over Line 5 is far from over: Michigan’s own lawsuit seeking to void the easement is still winding its way through state and federal courts, and the U.S. Supreme Court has agreed to review whether that case belongs in state or federal court.

Enbridge, which transports Canadian crude and refined products through the pipeline to the Midwest and eastern Canada, welcomed the decision. The company has maintained that Line 5 is safe and has continued operations throughout years of legal challenges. Federal authorities, supported by arguments from the U.S. government, argued in court that Whitmer’s shutdown order interfered with international energy trade and foreign policy.

Environmental and tribal groups continue to challenge the pipeline and related permitting decisions, including a proposed tunnel project meant to house Line 5 beneath the Straits. Those cases are moving through separate legal and administrative processes at the state and national level.

Line 5 Legal Battle — A Timeline

1953
Enbridge’s Line 5 pipeline begins operation under the Straits of Mackinac, carrying crude oil and natural gas liquids between Canada and the U.S.

2010
The Enbridge Line 6B spill in the Kalamazoo River raises scrutiny of pipeline safety statewide and intensifies opposition to Line 5.

2018–2019
Michigan commissions studies on Line 5 risks. Enbridge proposes building a tunnel beneath the Straits to house the pipeline.

2020
Gov. Gretchen Whitmer orders state regulators to revoke Line 5’s easement, citing environmental risk and violations of the public trust doctrine.

2021
Michigan Attorney General Dana Nessel files suit to shut down Line 5. Enbridge moves the case to federal court.

2023–2024
Lower courts rule that federal law governs pipeline safety, limiting Michigan’s authority to shut down Line 5.

December 2025
A federal judge rejects Whitmer’s attempt to shut down the pipeline, ruling that the Pipeline Safety Act preempts state action.

Pending
The U.S. Supreme Court is reviewing whether Michigan’s case belongs in state or federal court. Separate litigation over the tunnel project continues.

Why Federal Law Controls Pipeline Safety

The court’s ruling hinges on the Pipeline Safety Act of 1992, a federal law designed to create uniform national standards for interstate pipelines.

Key Points:

  • The law gives exclusive authority over pipeline safety to federal regulators

  • States may not impose their own safety rules on interstate pipelines

  • Congress acted to prevent a patchwork of state-by-state shutdown standards

The judge ruled that Michigan’s attempt to shut down Line 5 over safety concerns amounted to imposing state-level safety standards — something federal law explicitly prohibits.

The court emphasized that even legitimate environmental concerns do not override federal jurisdiction when Congress has preempted state authority.

In short:
Pipeline safety decisions for interstate lines are made at the federal level, not by governors or state agencies.

What Happens Next for Line 5

Despite the ruling, the Line 5 fight is far from over.

Still in Play:

  • Michigan’s broader lawsuit challenging the validity of the 1953 easement

  • U.S. Supreme Court review of jurisdiction (state vs. federal court)

  • Ongoing permitting and legal challenges to Enbridge’s proposed tunnel

What the Ruling Does:

  • Keeps Line 5 operating for now

  • Blocks Michigan from shutting down the pipeline on safety grounds

  • Reinforces federal control over interstate energy infrastructure

What It Doesn’t Do:

  • Resolve all legal challenges to Line 5

  • Approve or deny the tunnel project

  • End political or environmental opposition

Legal experts expect Line 5 to remain a multi-year legal and political battle, with energy security, environmental protection, and federal authority continuing to collide.

Michigan Energy Supply Impact: Line 5’s Role and What a Disruption Would Mean

Line 5 is a major artery of energy flow in Michigan and the broader Midwest, handling both crude oil and natural gas liquids critical to heating, transportation fuels and manufacturing.

How Much Energy It Moves

  • Line 5 transports up to 540,000 barrels per day (about 22.7 million gallons) of light crude oil, synthetic crude and natural gas liquids (NGLs).

  • Michigan relies on this flow for a substantial portion of its propane supply — roughly 55% statewide and about 65% in the Upper Peninsula.

Local Energy Uses

  • Propane carried via Line 5 is used for home heating, businesses and agriculture in areas where alternatives are limited.

  • Light crude delivered by Line 5 feeds refineries in Detroit and Toledo, which in turn produce gasoline, diesel and jet fuel used throughout Southeast Michigan, Ohio and beyond.

  • Beyond fuel, crude from Line 5 supports the manufacture of thousands of everyday products, from plastics to personal care items.

Consequences of a Shutdown

  • A complete Line 5 shutdown — even temporarily — would create an energy shortfall across the region:

    • Michigan could face up to a 756,000-gallon-per-day propane shortage, with limited short-term alternatives for transporting NGLs to market.

    • Refineries in Michigan, Ohio, Pennsylvania and Ontario would receive about 45% less crude from Line 5, intensifying supply pressures on gasoline, diesel and jet fuel.

No Easy Alternatives

  • The volume of crude and NGLs delivered by Line 5 cannot be replaced quickly by rail or truck; rail could provide less than 10% of the capacity if Line 5 were shut down.

  • Without Line 5, tanker trucks equivalent to about 90 trucks per hour would be needed to move the same products — a logistical and safety challenge for Michigan roads.

Broader Grid Context

  • While Line 5 does not directly carry electricity, its role in supplying fuel affects Michigan’s energy mix, which remains heavily reliant on fossil fuels for heat and transportation. According to federal data, natural gas and petroleum contribute a significant share of the state’s overall energy consumption.

Bottom Line: Line 5 is deeply embedded in Michigan’s energy economy — from heating homes in the U.P. to fueling refineries that supply transportation fuels. Disrupting that flow would have immediate and widespread impacts on energy supply, prices and logistics, underscoring why decisions about its operation are hotly contested.