A Tesoro Corp. (TSO:US) line in North Dakota that carries oil from the Bakken shale formation to a rail operation leaked about 20,000 barrels of crude near Tioga, in the northern part of the state.
Tesoro temporarily shut the segment involved and repairs were under way, the company said in a statement today.
Bakken crude priced in Clearbrook, N.D., weakened to a $14 discount against West Texas Intermediate on Oct. 7, compared with $10 below the domestic benchmark on Sept. 27, according to data compiled by Bloomberg. The differential narrowed to $12 a barrel as of 12:10 p.m. in New York.
The state was notified of the spill on Sept. 30, and the initial estimate of the amount released was 750 barrels, said Dave Glatt, chief of environmental health for North Dakota. He said the extent of the 7.3-acre spill was discovered later because much of the oil is below the surface, permeating the soil to a layer of clay 10 to 12 feet underground.
The line carried domestic crude to a rail site at Battleview, Maxine Herr, a spokeswoman for the state Mineral Resources Department in Bismarck, said by phone today.
The date of the release wasn’t known, Glatt said.
“It’s probably something that’s been going on for a little bit of a time, we just don’t know how long,” he said. “Due to the extent of what happened, what kind of leak was it and what kind of safeguards in place do they have to detect these things, that will be part of the investigation.”
A representative of the U.S. Pipeline and Hazardous Materials Safety Administration was at the site, Glatt said. A call to PHMSA wasn’t immediately returned.
To contact the reporter on this story: Eliot Caroom in New York at email@example.com