Michigan Republicans in Congress are urging President Joe Biden to oppose the closure of Line 5, warning of the potential consequences of shutting down the four-mile-long dual pipeline in the Straits of Mackinac. 

They recently wrote to Biden after he revoked the permit for the Keystone XL pipeline in his first week in office, citing "deep concerns" about the pressure to also shut down Enbridge Energy's Line 5 over environmental concerns. Michigan Gov. Gretchen Whitmer has said she has revoked Enbridge's easement for Line 5 in preparation for a May shutdown, but the issue will be decided in court.

The dual pipeline that runs under the Straits of Mackinac is part of a longer line that transports oil and natural gas liquids from Canada through Wisconsin and Michigan into Sarnia, Ontario.

The lawmakers in their letter said closing Line 5 would cost thousands of union jobs, close refineries and reduce energy supplies, including 15% of northwest’s Ohio’s fuel supply and 43% of southeastern Michigan’s supply.

Line 5 also supplies 65% of the propane used in Northern Michigan and Upper Peninsula, the representatives said.

"We respectfully request you consider these ramifications when making future decisions that ultimately affect the American economy, the environment and our immediate national energy needs," the lawmakers wrote. 

U.S. Rep. Tim Walberg, R-Tipton, spearheaded the letter, which 14 of his colleagues signed, including Reps. Fred Upton of St. Joseph, Jack Bergman of Watersmeet, Peter Meijer of Grand Rapids Township and Lisa McClain of Bruce Township.

Line 5 owner Enbridge Energy has been fighting to reverse Whitmer's plan to shut down the operation where it crosses the Straits of Mackinac.

Canada opposes closure, but Biden's Secretary of Transportation Pete Buttigieg advocated for the opposite when running for the Democratic presidential nomination.

A cabinet member in Prime Minister Justin Trudeau's administration said last week that the continued operation of the pipeline is "non-negotiable." Canada's natural resources minister Seamus O'Regan said that the Canadian government won't let Michigan shut down the pipeline.

"We are fighting for Line 5 on every front and we are confident in that fight," O'Regan told a special House of Commons committee on the relationship between Canada and the United States, according to the Canadian Press.

The Republicans noted that the proposal to replace the Line 5 pipeline with a tunnel under the straits would create jobs and 2 million work hours over the course of construction. The state approved permits in late January for the tunnel construction. 

Whitmer's office said in a statement last week that about 1.3 million jobs generating $82 billion in wages across the United States are supported by the Great Lakes and threatened by the risk of an oil spill in the Straits.

"These oil pipelines in the Straits of Mackinac are a ticking time bomb, and their continued presence violates the public trust and poses a grave threat to Michigan's environment and economy," Whitmer's office said.

"The governor fully stands behind her decision to revoke and terminate the 1953 easement, while securing Michigan’s energy needs.”

mburke@detroitnews.com

Staff writer Beth LeBlanc contributed.