By Vipal Monga

TORONTO -- Canadian and U.S. officials are at odds over the fate of a pipeline underneath the Great Lakes, exacerbating disagreements over energy policy between the two nations as the Biden administration prepares to take office.

Citing environmental concerns, Michigan state officials have told Enbridge Inc. to close its Line 5 pipeline, which carries more than half a million barrels of oil and natural gas liquids each day from Superior, Wis. to Sarnia, Ontario. Canadian officials say closing the pipeline would choke off more than half of the supply used to make gasoline, jet fuel and home-heating oil for the most populous parts of the country. The 645-mile pipeline, which is part of Enbridge's mainline system that conveys oil and natural gas liquids from Alberta, feeds refineries in Michigan, Ohio, Pennsylvania, Ontario and Quebec.

"Pipelines are so vital to the economy and the recovery," said Chris Bloomer president of the Canadian Energy Pipeline Association, a trade group. "We're hoping for some pragmatism."

The dispute adds another point of conflict in the energy relationship between the U.S. and Canada. Officials, companies and environmentalists in both countries have clashed in recent years over how to balance energy security with environmental concerns.

President-elect Joe Biden's team has said that he opposes a proposed extension of TC Energy Corp.'s Keystone pipeline, which would carry oil from Alberta to Nebraska. Canadian Prime Minister Justin Trudeau, who has long advocated for the extension, has said it would be a key issue between the two countries during Mr. Biden's tenure. Canadian officials said they expect Mr. Biden to stick with his plans to scrap the project.

Calgary-based TC Energy earlier this month started taking bids for space on the pipeline, saying that it was confident the project would get built. TC Energy has also proposed overhauls -- including a pledge to use only renewable energy -- in a bid to win Mr. Biden's support for the project. Environmental groups oppose the pipeline because of the threat of damage from spills and because they want to reduce the amount of oil extracted from Canada's oil sands.

Enbridge's Line 5 pipeline has drawn criticism from groups including the National Wildlife Federation and the Sierra Club, which say a spill would be catastrophic for the ecology of the Great Lakes.

Enbridge, also based in Calgary, said that the section of the 67 year-old pipeline that runs under the Straits of Mackinac has never leaked and that it is taking steps to further protect the lakes after negotiating a plan with former Michigan Gov. Rick Snyder to encase the pipes in a tunnel.

Michigan Gov. Gretchen Whitmer said in November that she was revoking a permit allowing the pipeline to run along the bottom of the Straits of Mackinac, between Lake Michigan and Lake Huron. Michigan's government said Enbridge had violated public trust and cited "the unreasonable risk" the pipelines pose to the Great Lakes. She gave the company until May 12 to shut the pipeline.

A spokesman for Canada's natural resources department said the government "supports the continued safe operation of Enbridge's Line 5." Doug Ford, the premier of Ontario, sent a letter to Ms. Whitmer last month saying that closing the pipeline would threaten union jobs in Ohio and Michigan. It could also force companies to transport fuel on trucks, trains and ships, worsening congestion on busy cross-border routes and increasing greenhouse-gas emissions, Mr. Ford said.

Enbridge sent a letter to Ms. Whitmer on Jan. 12 saying that only a court order or the federal Pipeline and Hazardous Materials Safety Administration carried the authority to shut the pipeline down. A PHMSA spokesman declined to comment.

Enbridge spokesman Mike Fernandez said the company has filed suit in the U.S. District Court for the Western District of Michigan to stop the closure and is lobbying government officials. Michigan is also suing Enbridge in the same court to affirm its order. No date has been set for proceedings in either case.

"Enbridge cannot unilaterally decide when laws and binding agreements apply and when they don't," said Dan Eichinger, director of Michigan's Department of Natural Resources, in a statement.

Closing the pipeline could lead to the loss of thousands of jobs at refineries and related companies in Sarnia, said Mike Bradley, mayor of the town of 75,000. He predicted that its closure would push up prices for gasoline, home heating oil, and jet fuel supplied to Toronto's Pearson Airport.

"There will be ripples all the way through," Mr. Bradley said.

Write to Vipal Monga at vipal.monga@wsj.com

Corrections & Amplifications

This item was corrected at 6:41 p.m. ET. An earlier version misstated President-elect Joe Biden's name as Bien.

(END) Dow Jones Newswires

01-19-21 0739ET