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Why a Decades-Old Pipeline Has Canada and Michigan at Odds

Why a Decades-Old Pipeline Has Canada and Michigan at Odds

For 70 years, the Line 5 pipeline has supplied light oil and propane to refineries and homeowners in the U.S. Midwest and the Canadian provinces of Ontario and Quebec without much controversy. Recently, that’s changed. The line’s crossing under a key waterway linking Lake Michigan and Lake Huron has stirred a standoff between Calgary-based Enbridge Inc., the line’s operator, and Michigan Governor Gretchen Whitmer, who wants it shut. The controversy is sparking a political conflagration in the U.S., drawing in the Biden administration and straining relations with longtime ally Canada. 

1. What is Line 5? 

Capable of carrying 540,000 barrels a day, the pipeline originates at an Enbridge oil terminal in Wisconsin. Moving eastward, it traverses the upper Michigan peninsula before crossing under the Straits of Mackinac to the lower peninsula. It crosses the U.S.-Canada border to reach Sarnia, Ontario, where it connects to another pipeline that runs as far as Quebec. The line supplies more than half of Michigan’s propane, according to Enbridge, and is also a key conduit of light crude oil for refineries in Michigan, Ohio, Pennsylvania, Ontario and Quebec. 

2. Why is it in the news?

Whitmer, Michigan’s Democratic governor, says Line 5 is a threat to the Great Lakes and has ordered Enbridge to shut it down. “The two aging, 4.5-mile sections of underwater pipeline are a ticking time bomb,” she wrote in the Washington Post in May. (Line 5 splits into two parallel 20-inch-diameter pipelines under the Straits of Mackinac.) Enbridge has defied the order; it’s also seeking approval to construct a tunnel around that section of pipeline to ensure safety. Court-ordered mediation fell through in September, leaving Whitmer and Enbridge to fight out their differences in federal court. 

3. What do the U.S. and Canada say?

The government of Canadian Prime Minister Justin Trudeau backs Enbridge, saying that the pipeline’s continued operation is nonnegotiable. It recently invoked a provision in a 1970s-era treaty to defend the line’s operation, raising the matter to the international level. U.S. President Joe Biden’s administration says it will discuss the matter with its northern neighbor and stressed that it’s not considering forcing a shutdown. Biden is an ally of Whitmer and has taken a hard line so far on oil pipelines, canceling the controversial Keystone XL project that would have delivered Canadian crude to the U.S. But shutting Line 5 could raise energy costs in Michigan, a political battleground state, at a time when Republicans are blaming him for rising fuel prices. It would also undermine relations with Trudeau’s government.

4. Why is this happening now?

In June 2020, a Michigan judge ordered Enbridge to temporarily shut the pipeline after damage was detected along a segment of the underwater line. That episode elevated concerns about the potential harm to the Great Lakes -- the interconnected freshwater lakes that connect to the Atlantic Ocean via the St. Lawrence River. Opponents of Line 5 also note that in 2010, a different Enbridge pipeline spilled more than 20,000 barrels into a Michigan creek that flowed into the rain-swelled Kalamazoo River, becoming one of the largest inland oil spills in U.S. history. 

5. What does Enbridge say?

The company says Line 5 has operated safely for decades and its plan to build a tunnel under the waterway to house the pipeline will make the threat of spills virtually zero. The tunnel plan is currently under review by the U.S. Army Corps of Engineers. Meanwhile, Enbridge argues that shutting the pipeline would require tens of thousands of trucks and hundreds of rail cars to transport oil and fuel by road and raise propane prices for Michigan homeowners that rely on the fuel to heat their homes.

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