Company says thousands of gallons of oil have been recovered from a pipeline spill in North Dakota

BISMARCK, N.D. (AP) — Workers have recovered thousands of gallons of crude oil from an underground pipeline spill on North Dakota farmland, the owner of the line said Thursday, but it remains unclear when oil will again start flowing to refineries.

South Bow is still investigating the cause of the spill Tuesday along the Keystone Pipeline near Fort Ransom, North Dakota, about 60 miles (97 kilometers) southwest of Fargo, the company said.

The spill released an estimated 3,500 barrels, or 147,000 gallons of oil, onto farmland. The company said 700 barrels, or 29,400 gallons, have been recovered so far. More than 200 workers are on-site as part of the cleanup and investigation.

South Bow has not set a timeline for restarting the 2,689-mile (4,327 kilometers) pipeline, which stretches from Alberta, Canada, to refineries in Illinois, Oklahoma and Texas. The company said it “will only resume service with regulator approvals.”

A map from the company shows the pipeline is shut down from Alberta, Canada, to points in Illinois and a liquid tank terminal in Oklahoma. The line is open between Oklahoma and points on Texas’ Gulf Coast, according to the map.

South Bow is working with the federal Pipeline and Hazardous Materials Safety Administration and the state Department of Environmental Quality.

Continuous monitoring of air quality hasn't indicated any adverse health or public concerns, South Bow said.

The site remains busy, said Myron Hammer, a nearby landowner who farms the land affected by the spill. Workers have been bringing in mats to the field so equipment can access the site, and lots of equipment is being assembled, he said.

The area has traffic checkpoints, and workers have been hauling gravel to maintain the roads, Hammer said.

There is a cluster of homes in the area, and residents include retirees and people who work in nearby towns, he said. But the spill site is not in a heavily populated area, Hammer said.

The pipeline shutdown means that refineries that rely on crude oil will have 3% to 4% less of the total flows in a daily market of 17 million to 20 million barrels, said Ramanan Krishnamoorti, vice president for energy and innovation at the University of Houston.

“It's hard to see how you replace that into the stockpile that goes into these refineries,” he said. “Typically you have storage of crude in storage tanks and ships and everything. That might be a few days. But when you start to lose 3%, 4% of daily demand, it's going to have impacts.”

Gas prices in the Midwest have already seen an increase that is likely to grow, and diesel prices could be impacted significantly and quickly, he said.

Mark LaCour, editor-in-chief of the Oil and Gas Global Network, said he doesn’t think the pipeline shutdown will affect the middle of the country dramatically. But if it stays down, in two or three weeks there will be a significant price increase in the Midwest, he said.

Underground oil pipelines can be subject to a number of problems, both internal and external, said Robert Hall, a senior technical adviser with the Pipeline Safety Trust who was previously the director of the Office of Railroad, Pipeline and Hazardous Materials Investigations at the National Transportation Safety Board.

Pipelines can face internal factors such as corrosion and pressure fluctuations. The latter can lead to fatigue and cracks, Hall said. External threats include corrosion, dents, gouges and construction damage, he said.

Pipelines are the safest method for transporting petroleum products, Hall said.

“Just based on the accident history, if you look at the accidents that have occurred with trains, trucks and barges, there are collisions,” he said, citing a 2013 oil train derailment in Quebec that killed 47 people.