Exxon shut the Pegasus pipeline, which can carry more than 90,000 barrels per day (bpd) of crude oil from Pakota, Illinois, to Nederland, Texas, after the leak was discovered on Friday afternoon, the company said in a statement.
Exxon, hit with a $1.7 million fine by regulators this week over a 2011 spill in the Yellowstone River, said a few thousand barrels of oil had been observed.
A company spokesman confirmed the line was carrying Canadian Wabasca Heavy crude. That grade is a heavy bitumen crude diluted with lighter liquids to allow it to flow through pipelines, according to the Canadian Energy Pipeline Association (CEPA), which referred to Wabasca as “oil sands” in a report.
The spill occurred as the U.S. State Department is considering the fate of the 800,000 bpd Keystone XL pipeline, which would carry crude from Canada’s oil sands to the Gulf Coast. Environmentalists, concerned about the impact of developing the oil sands, have sought to block its approval.
Supporters say Keystone will help bring down the cost of fuel in the United States.
The Arkansas spill was the second incident this week where Canadian crude has spilled in the United States. On Wednesday, a train carrying Canadian crude derailed in Minnesota, spilling 15,000 gallons of oil.
Exxon expanded the Pegasus pipeline in 2009 to carry more Canadian crude from the Midwest to the Gulf Coast refining hub and installed what it called new “leak detection technology”.
Exxon said federal, state and local officials were on site and the company said it was staging a response for a spill of more than 10,000 barrels “to be conservative”. Clean-up crews had recovered approximately 4,500 barrels of oil and water.