Line 5 in the Straits of Mackinac

Enbridge Defies Gov. Whitmer’s Order to Shut Down Line 5

On November 13, 2020, Michigan Gov. Gretchen Whitmer took decisive action to shut down Line 5 by May of 2021 under the Public Trust Doctrine to protect the Great Lakes from the risk of a catastrophic oil spill.

The State of Michigan is revoking and terminating the 1953 easement that Canadian-company Enbridge has relied on to operate its dual Line 5 pipelines in  the open waters of the Straits of Mackinac due to repeated violations of the easement. This historic action represents a clear victory for the Great Lakes and the citizens and tribes of Michigan, and recognizes that alternatives to Line 5 exist for supplying oil and propane. The State of Michigan, however, must remain vigilant until the oil stops flowing for good because Enbridge is defying the shutdown order, and Line 5 remains exposed to exceptionally strong currents, lakebed scouring, new anchor and cable strikes, and corrosion.

What is Line 5?

Map courtesy of Sierra Club

Built in 1953 and designed to last 50 years, the Line 5 pipeline runs from Superior, Wisconsin, across the Upper Peninsula of Michigan, through the open waters of Straits of Mackinac, and across the Lower Peninsula, before crossing under the St. Clair River to refineries in Sarnia, Ontario. The 30-inch-diameter steel pipeline splits into two 20-inch-diameter pipes when crossing the Straits, carrying nearly 23 million gallons of oil and natural gas liquids daily through the turbulent waters where Lake Michigan meets Lake Huron. Line 5 has failed at least 33 times since 1968, spilling at least 1.13 million gallons of oil on land and in wetlands. These 68-year-old Line 5 runs at depths between 100 and 270 feet in the Straits of Mackinac, where it is stressed by strong currents and prone to anchor strikes. Built and operated by Canadian company, Enbridge, Inc., Line 5's products mostly serve Canada, with less than 10 percent of the oil used in Michigan. Line 5 threatens the drinking water supply for 5 million Michigan residents, the Pure Michigan tourist economy, and a way of life. It is time for the state of Michigan to evict Enbridge from the Straits of Mackinac and shut down Line 5 because of the oil spill danger to the Great Lakes.

What is the Oil Tunnel?

Enbridge is proposing to bore and blast a 20-foot-in-diameter oil tunnel under the Straits of Mackinac to house a new Line 5 pipeline. The Canadian company’s goal is to continue for another 99 years carrying up to 23 million gallons of oil and natural gas liquids a day through Line 5 and the public trust bottomlands where Lake Michigan meets Lake Huron. FLOW and our partners have identified critical deficiencies in the project’s construction permit application, its legal authorization, and the review by state environmental agencies of expected impacts to wetlands, bottomlands, and surface water, including from the daily discharge of millions of gallons of wastewater during construction. FLOW has deep concerns about the lack of public necessity for the project, which would worsen climate change and related impacts to the Great Lakes. Learn more.

Quick Facts

  • Enbridge’s data reveal that sections of Line 5 in the Mackinac Straits are cracked and dented, and a segment on land near the Straits has lost 26% of its original wall thickness.
  • Under the best conditions, only 30% of an oil spill would be recovered.
  • 1.5 million jobs are directly tied in some way to the Great Lakes, generating more than $62 billion in wages.

Line 5 Webinars

FLOW held a webinar in July 2021 — The Battle Over Line 5: The Legal Fight for Our Public Waters — that explored legal, economic, regulatory, tribal treaty, and frontline insights in support of the State of Michigan’s case to shut down Line 5 in the Straits of Mackinac. Watch the webinar below:

FLOW held two summer 2020 webinars that examined the path forward to shut down Line 5: Exploring Legal Pathways to Shut Down Line 5 and Stop Oil Tunnel to Protect the Great Lakes on July 22 and Securing a Brighter Future Without Line 5 or an Oil Tunnel on August 5. Watch them below:

Line 5 Storymap: The Legal Fight for Our Public Waters

FLOW has produced a dynamic and engaging multimedia story map to provide the most current information on the threat from, and solutions to, the decaying Line 5 oil pipelines in the Straits of Mackinac and the proposed oil tunnel under the Great Lakes. Our Line 5 digital story map (see directly above or click here to open in a new tab) includes interactive maps and links to new videos, fact sheets, and more, as well as sections about the history and route of the oil pipelines; the threats they pose; the Public Trust and your rights; tribal concerns; the latest news on shutting down Line 5; alternatives that ought to be pursued; and how you can take action today. The maps are interactive, so click and zoom for more details. Links to videos, photos, websites, and other pop-up images will be highlighted. Click on any tab in the Line 5 story map to learn more about that topic.

A Looming Threat to Michigan's Economy

A spill from Line 5 at the Straits of Mackinac could deliver a blow of over $6 billion in impacts and natural resource damages to Michigan’s economy, according to a study commissioned by FLOW. Conducted by nationally respected ecological economist Robert Richardson of Michigan State University, the study for the first time adds up potential costs of a Line 5 spill into the Straits of Mackinac and adjoining waters under a realistic – but not worst-case – scenario.  The study estimates $697.5 million in costs for natural resource damages and restoration and more than $5.6 billion in total economic impacts, including:

  • $4.8 billion in economic impacts to the tourism economy; 
  • $61 million in economic impacts to commercial fishing;
  • $233 million in economic impacts to municipal water systems;
  • Over $485 million in economic impacts to coastal property values. 

Enbridge Energy is using the Straits of Mackinac as a convenient shortcut for transporting oil from the Canadian prairies to a Canadian refinery in Sarnia, with precious little of its product benefiting Michigan.  Yet Michigan would absorb the lion’s share of the economic disaster resulting from a spill.

Nancy May

An Imminent Threat to the Great Lakes

In early April, we dodged a bullet as we watched a hazardous liquid spill from two neighboring transmission cables unfold.  A release of at least 600 gallons of toxic coolant and insulating fluid from electric cables owned by American Transmission Company (ATC) occurred sometime Sunday, April 1 in the Straits of Mackinac.  ATC, however, did not report the release to the Coast Guard for 24 hours. By Monday, ATC officials were blaming “extraordinary circumstances” like ice in the water and near the shore that hindered the emergency response. 

On April 3, Enbridge – owner and operator of Line 5 – temporarily shut down the flow of oil in the pipelines to evaluate leak detection systems. Ten days after the ATC accident, on April 10, Enbridge notified state and federal officials that their pipelines had suffered three dents due to the same vessel that damaged the ATC lines.

A vessel anchor strike to Line 5 was the number one threat that consultant Dynamic Risk identified in its November 2017 alternative report to the Governor Snyder’s Michigan Pipeline Safety Advisory Board.  Ironically, the original Bechtel engineers believed that a vessel anchor strike was only “one chance in a million.”

Well, that one chance in a million became real. 

A Collection of Line 5 Films

Great Lakes, Bad Lines from Colin McCarthy on Vimeo.

FLOW partnered with Patagonia to create the short film Great Lakes, Bad Lines, which takes a first-hand look at the insurmountable threat that Line 5 poses to our waters. Click here to watch at home, or plan a screening.

Straight Talk about Line 5 Through the Straits from rivetentertainment on Vimeo.

This video was produced to point out the failings of the Enbridge Line 5 oil pipeline that runs through 21% of the world's fresh surface water in the middle of the Great Lakes. Produced by Rivet Entertainment

Before the Spill from Adam Wells on Vimeo.

Every day 23 million gallons of oil are pumped under the largest freshwater system on the planet, putting over 450 miles of shoreline and 100,000 acres of water at risk. The Great Lakes supply drinking water to 40 million people, provide crucial habitat to 47 species, and support a handful of multi-billion dollar industries. Line 5 expired fifteen years ago. It’s not a matter of if it spills, but when. Filmmkaer Adam Wells worked with businesses, nonprofits, scientists, the Grand Traverse Band of Ottawa and Chippewa Indians, and residents across the state to create Before the Spill, a film about Line 5, its risks, and the best path forward.

Want to see what Line 5 looks like up close? Watch this three-minute underwater tour courtesy of Dr. Ed Timm.

Immiscible: The Fight Over Line 5 explores the growing tension between water activists and big oil companies. The film features interviews from leading organizations in the fight to decommission Enbridge Line 5 in the Straits of Mackinac, members of indigenous communities at risk, concerned residents, as well as Enbridge Energy’s public response to this conflict. This film was created by four Michigan State University students (Olivia Dimmer, Daniel Stephens, Austin Torres, & Annette Kim) in the College of Communication Arts & Sciences, Department of Media & Information.

Enbridge's Easement Violations

FLOW has revealed that Enbridge is operating illegally and has broken its easement agreement with the state and people of Michigan in the following ways:

  1. Standard of Care as a Reasonably Prudent Person (Section A)
  2. Indemnity Provision (Section J)
  3. Pipeline Wall Thickness Provision (Section A (11))
  4. Pipeline Exterior Slats and Coating Requirements (Section A (9))
  5. Pipeline Minimum Curvature Requirement (Section A (4))
  6. Maximum Unsupported Span Provision (Section A (10))
  7. Federal Violation of Emergency Oil Spill Response Plan (Section A)
  8. State Violation under the Michigan Environmental Protection Action (Section A)


Read the Full Report here.

Alternatives Exist

FLOW's December 2015 expert report demonstrates that decommissioning the Line 5 oil pipeline would not disrupt Michigan's or the Midwest's crude oil and propane supply, as only 5-10% of the oil in Line 5 is used in Michigan. Available capacity to meet energy demand in the Great Lakes region already exists in the North American pipeline system. Check out our Alternatives Fact Sheet below for more information.

FLOW and our partners are working together to ensure that the State of Michigan is held accountable as public trustee of our waters to take immediate action to prevent a catastrophic oil spill in the Great Lakes.