Officials say the Keystone oil pipeline has ruptured in North Dakota, with the spill confined to an agricultural field

FORT RANSOM, N.D. — The Keystone oil pipeline ruptured Tuesday morning in North Dakota, with the spill confined to an agricultural field.

The cause of the rupture and the volume of crude oil spilled were not immediately unclear. An employee working at the site near Fort Ransom heard a “mechanical bang” and shut down the pipeline within about two minutes, said Bill Suess, spill investigation program manager with the North Dakota Department of Environmental Quality.

Oil was reported surfacing 300 yards (274 meters) south of the pump station in a field, Suess said. Emergency personnel responded to the site, Suess said.