TIOGA Cleanup crews have been on site for an oil pipeline owned by Tesoro that spilled 20,600 barrels, or about 865,200 gallons, of crude oil in a wheat field near Tioga.
The spill happened about 8 miles northeast of Tioga.
The spill, covering an area the size of about seven football field, was discovered Sept. 29 by a farmer harvesting wheat and the cleanup crews have been there since, said Kris Roberts, environmental geologist. About 1,165 barrels of oil have been recovered. A barrel is 42 gallons.
Roberts said the spill has been contained and no water sources have been contaminated.
The Associated Press, who contributed to this story, said Tesoro officials did not immediately return their phone calls seeking comment on Thursday.