An aboveground section of Enbridge's Line 5 at the Mackinaw City, Mich., pump station, in October 2016.John Flesher/The Associated Press
The Enbridge Line 5 pipeline is at the centre of a legal dispute that now features Ottawa, Michigan, and various state chambers of commerce and Canadian provinces. The 68-year-old pipeline lies on the lake bed of the narrows between Lake Michigan and Lake Huron, in the Straits of Mackinac.
Here’s what you need to know about the pipeline, the environmental concerns surrounding it and possible resolutions to the dispute.
Latest news: On eve of trade talks, Canada warns United States against shutting down Line 5
What is the route of the Enbridge pipeline Line 5?
Line 5 is part of Calgary-based Enbridge Inc.’s pipeline network, which ships Canadian petroleum across North America. Line 5 starts at the port of Superior, Wis., on the western tip of Lake Superior. From there it heads east to Michigan’s rural Upper Peninsula. Before it reaches the end of the peninsula, it veers south across an environmentally sensitive waterway called the Straits of Mackinac, which connects Lake Michigan and Lake Huron. The single pipeline splits into two pipes for the 7.2-kilometre water crossing, then merges back into one when it reaches Lower Michigan. From that point it heads south and then east to Marysville, Mich., where it crosses the Canada-U.S border into Sarnia, Ont. It’s been operating for 68 years and transports as much as 540,000 barrels per day of light crude oil, light synthetic crude and natural gas liquids.
DETAIL
Straits of Mackinac
Proposed pipeline
replacement segment
Mackinac
Bridge
Existing Line 5
dual pipelines
Pipeline and tunnel
easements
Mackinaw City
0
900
METRES
MICHIGAN
CANADA
Mackinaw
City
Superior
Enbridge’s energy
infrastructure
Sarnia
U.S.
Liquids pipeline
Enbridge Line 5
pipeline
Line 78
Liquids pipeline
(proposed)
Natural gas
transmission pipeline
Natural gas gathering
pipeline
Natural gas liquids
pipeline
JOHN SOPINSKI/THE GLOBE AND MAIL, SOURCE: ENBRIDGE;
government of michigan
DETAIL
Straits of Mackinac
Proposed pipeline
replacement segment
Mackinac
Bridge
Existing Line 5
dual pipelines
Pipeline and tunnel
easements
Mackinaw City
0
900
METRES
MICHIGAN
CANADA
Mackinaw
City
Superior
Enbridge’s energy
infrastructure
Sarnia
U.S.
Liquids pipeline
Enbridge Line 5
pipeline
Line 78
Liquids pipeline
(proposed)
Natural gas
transmission pipeline
Natural gas gathering
pipeline
Natural gas liquids
pipeline
JOHN SOPINSKI/THE GLOBE AND MAIL, SOURCE: ENBRIDGE;
government of michigan
DETAIL
Straits of Mackinac
Proposed pipeline
replacement segment
Mackinac
Bridge
Existing Line 5
dual pipelines
Pipeline and tunnel
easements
Mackinaw City
0
900
METRES
MICHIGAN
CANADA
Mackinaw
City
Superior
Enbridge’s energy
infrastructure
Sarnia
UNITED STATES
Liquids pipeline
Line 78
Enbridge Line 5
pipeline
Liquids pipeline
(proposed)
Natural gas
transmission pipeline
Natural gas gathering
pipeline
Natural gas liquids
pipeline
JOHN SOPINSKI/THE GLOBE AND MAIL, SOURCE: ENBRIDGE; government of michigan
Is Line 5 going to be shut down?
It’s up to the courts at the moment. Michigan Governor Gretchen Whitmer campaigned in 2018 on a promise to shutter the line, and in November, 2020, served notice that she was revoking the easement permit that allows Line 5 to cross the Straits of Mackinac, citing the risk of oil spills. She gave Enbridge 180 days to comply. Michigan’s Attorney-General filed a lawsuit in state court seeking a judge’s order to enforce the measure.
But Enbridge has challenged these actions in U.S. federal court, arguing only the federal government can pass judgment on the safety of a pipeline. And the company is defying Ms. Whitmer, saying it will not shut the line down unless ordered to do so by a judge. The state is seeking to have the matter sent back to state-level court. Enbridge and Michigan are now in court-ordered mediation talks.
The Canadian government has warned it is prepared to intervene in the matter, even if that means invoking a 1977 treaty between Canada and the U.S. that was designed to prevent “uninterrupted transmission by pipeline” of petroleum passing through each side’s territory. The treaty says the only justifications for impeding the flow are natural disasters or emergencies – and these may only be temporary interruptions. It also sets up binding arbitration for disputes. So far, Canada has held off invoking the treaty as it watches the court case unfold.
Is there a replacement for the pipeline?
For months, oil companies have been developing contingency plans in case Line 5 is shuttered. Those largely involve transporting crude by rail, tanker trucks or Great Lakes barges – a proposal Michigan Chamber of Commerce CEO Richard Studley has called an “insanely bad idea.”
Ms. Whitmer said in 2018 that trucks or boats could replace the pipeline, and this week her administration released a plan to make sure Michigan will have enough propane if Line 5 is shut down. That plan calls for more state investment in rail and propane storage infrastructure, as well as efforts to find new suppliers and working with the industry to deal with potential shortages. It also proposes more energy efficiency and greater use of other energy sources, including renewables.
Capacity of Enbridge pipelines (barrels/day)
Line 5
540,000
Line 78
570,000
Line 78 (ex-Stockbridge)
502,000
Demand on Enbridge pipelines (barrels/day)
Line 5 (including NGL)
500,000
Line 78
480,000
If Line 5 were shut down (U.S. gallons/day)
Daily propane supply
shortage for Mich.
756,000
Daily shortage of gas,
diesel and jet fuel for Mich.,
Ohio, Penn., Ont. and Que.
14,700,000
Daily shortage of gas,
diesel, jet fuel
and propane for Mich.
4,200,000
to 7,770,000
JOHN SOPINSKI/THE GLOBE AND MAIL, SOURCE: ENBRIDGE
Capacity of Enbridge pipelines (barrels/day)
Line 5
540,000
Line 78
570,000
Line 78 (ex-Stockbridge)
502,000
Demand on Enbridge pipelines (approx.) (barrels/day)
Line 5 (including NGL)
500,000
Line 78
480,000
If Line 5 were shut down (U.S. gallons/day)
Daily propane supply
shortage for Mich.
756,000
Daily shortage of gas,
diesel and jet fuel for Mich.,
Ohio, Penn., Ont. and Que.
14,700,000
Daily shortage of gas,
diesel, jet fuel
and propane for Mich.
4,200,000
to 7,770,000
JOHN SOPINSKI/THE GLOBE AND MAIL, SOURCE: ENBRIDGE
Capacity of Enbridge pipelines (barrels/day)
Line 5
540,000
Line 78
570,000
Line 78 (ex-Stockbridge)
502,000
Demand on Enbridge pipelines (approx.) (barrels/day)
Line 5 (including NGL)
500,000
Line 78
480,000
If Line 5 were shut down (U.S. gallons/day)
Daily propane supply shortage
for Mich.
756,000
Daily shortage of gas,
diesel and jet fuel for Mich.,
Ohio, Penn., Ont. and Que.
14,700,000
Daily shortage of gas,
diesel, jet fuel
and propane for Mich.
4,200,000
to 7,770,000
JOHN SOPINSKI/THE GLOBE AND MAIL, SOURCE: ENBRIDGE
What are the environmental concerns about Line 5?
Line 5 is the latest Canadian-operated pipeline to fall victim to U.S. concerns about transmission safety. Fear of an oil spill in the Great Lakes is the biggest environmental concern. The pipeline is submerged when it crosses the Straits of Mackinac. In November, when Ms. Whitmer announced she was revoking the easement permit, she cited instances in 2018 and 2019 when the pipelines were struck, but not punctured, by anchors or cables from vessels.
Enbridge says the pipeline has never leaked into the Straits of Mackinac, but critics note it has leaked elsewhere along the route. They also point to 2010, when another pipeline operated by Enbridge, Line 6B, ruptured and released 3.3 million litres of oil into a tributary of the Kalamazoo River. That became one of the largest inland oil spills in U.S. history and took five years to clean up.
Environmental critics say the currents at the straits could spread an oil spill far and wide. A University of Michigan computer-modelling study in 2016 concluded that more than 1,120 kilometres in Lake Huron and Lake Michigan would be vulnerable to oil spills if the pipelines beneath the Straits of Mackinac were to rupture.
“The peak flow in the straits is 10 times the flow over Niagara Falls,” said Sean McBrearty, the Michigan legislative and policy director with environmental group Clean Water Action.
Mr. McBrearty said fears about the Line 5 Straits of Mackinac crossing – situated in a busy shipping lane – really began to mount after the Kalamazoo oil spill.
Mackinac Island, close to the Line 5 crossing, is a beloved vacation destination for Michiganders. It also holds a central place in the traditions, culture and history of Indigenous people in the region. More than 80 per cent of it is a state park.
“The water is absolutely pristine,” Mr. McBrearty said. “Mackinac Island is one of Michigan’s biggest tourist attractions.”
A 2018 poll of Michigan voters found 54 per cent of respondents supported shutting down the pipeline crossing of the straits. The poll, commissioned by the National Wildlife Federation and conducted by a local research firm, EPIC-MRA, also found 87 per cent of respondents were concerned that Line 5 could rupture and leak oil in the Great Lakes. The survey polled 600 adults and had a margin of error of plus or minus 4 per cent. Enbridge publicly questioned the poll and suggested it posed leading questions.
“You think about what happened in the Gulf of Mexico with the Deepwater Horizon, and that happening in the Great Lakes, and people react to it in a very visceral way, like ‘Why would we even take that risk?’,” said Jonathan Hanson, a lecturer at the University of Michigan’s Gerald R. Ford School of Public Policy.
Enbridge, for its part, says it has learned its lesson from the Kalamazoo River spill. Every employee of the Calgary company is given a ring made with metal from the failed pipe to remind them of the need for pipeline safety. “Since then, Enbridge has transformed its approach to safety, investing heavily in enhanced monitoring, safer pipelines and more staff to keep operations safe,” Enbridge spokeswoman Tracie Kenyon said. She said there are automatic shut-off valves on Line 5 on either side of the straits and employees keep a close watch over pipeline pressure, movement and vibration.
Is there any way to resolve concerns about Line 5′s water crossing at the Straits of Mackinac?
Enbridge has proposed building a US$500-million tunnel that would run deep under the straits so the Great Lakes would be shielded from possible accidents. While the primary idea is to accommodate a new Line 5 pipeline segment to replace the current, aging pipe, the state says it could also be used down the road for other utility infrastructure, including electric transmission lines and cables for data and telecommunications.
Profile view of proposed tunnel
Ordinary high water mark: 580.5 feet
600 ft.
500
Lake
Lake bed
400
300
200
Rock
Tunnel will be
constructed within
these limits
100
0
JOHN SOPINSKI/THE GLOBE AND MAIL, SOURCE: ENBRIDGE;
government of michigan
Profile view of proposed tunnel
Ordinary high water mark: 580.5 feet
600 ft.
500
Lake
Lake bed
400
300
200
Rock
Tunnel will be
constructed within
these limits
100
0
JOHN SOPINSKI/THE GLOBE AND MAIL, SOURCE: ENBRIDGE;
government of michigan
Profile view of proposed tunnel
Ordinary high water mark: 580.5 feet
600 ft.
500
Lake
Lake bed
400
300
200
Rock
Tunnel will be
constructed within
these limits
100
0
JOHN SOPINSKI/THE GLOBE AND MAIL, SOURCE: ENBRIDGE; government of michigan
“The Great Lakes Tunnel will be bored through rock, as much as 100 feet below the lake bed – virtually eliminating the chance of a pipeline incident in the Straits,” Enbridge says on a corporate website explaining the proposal.
In December, 2018, the administration of then-governor Rick Snyder entered into an agreement with Enbridge that included provisions for increased Line 5 maintenance and prohibited using the new pipeline to transport heavy crude oil.
Enbridge says it would take three years to build the tunnel, but it’s still awaiting regulatory approval.
Clean Water Action’s Mr. McBrearty argues this solution comes too late. In the meantime, he said, fears of an oil spill remain high.
A business coalition in support of the Great Lakes Tunnel commissioned a poll in September, 2020, that found 60 per cent of Michigan respondents backed the proposed project. The poll by TargetPoint Consulting, a self-described conservative research firm, surveyed 800 registered voters and had a margin of error of plus or minus 3.46 per cent.
What are the pros and cons of Line 5 in Canada and the U.S.?
The benefits of Line 5 are clear for Canada: it’s a vital conduit of petroleum for Ontario and Quebec. The Canadian Chamber of Commerce has warned of significant disruption to fuel supplies to Canada’s two most populous provinces if Line 5 ceases operation, while the federal government has warned that a shutdown would represent a threat to the country’s energy security. As Ottawa wrote in a legal filing May 11, “Line 5 supplies approximately 66 per cent of Quebec’s crude oil needs and about 50 per cent of the [petroleum] used by Ontario’s refineries to make gasoline and other fuels.”
Line 5 also delivers petroleum products to Michiganders, but a chief criticism of the pipeline in Michigan is that it transits through the state merely because it’s the fastest route from Western Canada to Central Canada – and that it delivers insufficient benefit to the state itself.
“You hear that in the debate. [Critics] say, ‘Why is Michigan just a transit point for a Canadian company to run this line through our state?’” Mr. Hanson said.
Enbridge rejects the argument that the pipeline is of little benefit to Michiganders. It says that while a significant portion of Line 5 continues on to Canada, there are still benefits for Michigan and the region. It says Line 5 supplies 55 per cent of the state’s propane needs, including approximately 65 per cent of the propane used in the Upper Peninsula and northern Michigan.
Enbridge’s Ms. Kenyon says shipments from Line 5 support refineries in Michigan, Ohio and Pennsylvania. Refiners produce goods such as gasoline, diesel and jet fuel for the region. Some petroleum is turned into propane in Sarnia and returned to Michigan, the company notes. Enbridge also says the pipeline takes Michigan-produced oil to market and has delivered 80 million barrels from the state over its lifetime.
More reading
Opinion and Analysis
Konrad Yakabuski: A weakened Biden throws Canada under the bus, again
Laurence Martin: With the Line 5 shutdown order, the U.S. spurns Canada’s energy needs again
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