Keystone oil pipeline shut down after "mechanical bang" reported

The Keystone Pipeline was shut down after a "bang" was reported Tuesday morning, according to Bill Suess, spill investigation program manager with the North Dakota Department of Environmental Quality.

"An employee on a pump station heard what was described as a mechanical bang" at 7:44 a.m., Suess told CBS News, adding that the employee immediately shut down the pipeline and notified emergency personnel.

A release of product from the pipeline was confined to an agricultural field south of the pump station, Suess said.