Preliminary findings show a fatigue crack caused a Keystone Pipeline oil spill in North Dakota

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BISMARCK, N.D. (AP) — A fatigue crack in the Keystone Pipeline led to an oil spill in North Dakota earlier this year that released thousands of barrels of oil onto farmland, according to the pipeline operator.

In a quarterly report released Thursday, South Bow said initial findings show, “the failure resulted from a fatigue crack that originated along the pipe’s manufactured long-seam weld.” A fatigue crack develops from stress over time. A mechanical and metallurgical analysis found the pipe and welds met industry standards, the company said.

Spill-related costs total around $55 million, which the company said it expects to recover through insurance early next year. Through September, South Bow had received about $16 million in reimbursements from its insurance policies.

The U.S. Pipeline and Hazardous Materials Safety Administration ordered several corrective actions after the spill. The federal government shutdown delayed the release of a third-party “root cause analysis,” South Bow said.

It's unclear when those findings will come. A South Bow spokesperson said PHMSA is leading that process and “out of respect for the process, we can’t speak for them.”

The spill occurred April 8. An employee at the rural site about 60 miles southwest of Fargo heard a “mechanical bang” and shut down the pipeline within two minutes, a state official has said.

An estimated 3,500 barrels or 147,000 gallons of oil spilled in a field near Fort Ransom, a small town in a forested area with outdoor recreation and scenic views. South Bow sent vacuum trucks and more than 200 workers to aid the cleanup. The pipeline restarted after a six-day shutdown.

State regulators inspected the site several times in the months after the spill, noting in September that “the vegetation is recovering well,” and that it should be checked again in spring 2026, according to an incident report.

Nearly 90% of the spilled oil was recovered, according to the report. Crews removed impacted soil to be disposed of elsewhere.

Local landowner Myron Hammer said South Bow's cleanup was completed in time for him to plant a soybean crop on the land.

“I'm surprised that they got everything put back in place as quick as they did. It was a big project,” he said.

Roughly 5 acres of land were impacted by the spill, though South Bow utilized 40 acres or more for the entire staging area and access, Hammer said. People and vehicles were on site as recently as Thursday, he said. The area of the spill is in gently rolling farmland.

The company said it has conducted numerous remedial evaluations of the pipeline and found “no injurious issues” so far, with more in-line inspections and integrity digs to come.

The nearly 2,700-mile (4,345 kilometers) Keystone Pipeline transports crude oil from Alberta, Canada, to refineries in Illinois, Oklahoma and Texas. The pipeline moved an average 580,000 barrels per day from January through September of this year, South Bow said.