An oil storage facility in North Dakota owned by Hess Corp leaked about 32,000 gallons on Tuesday, though the crude has been recovered on site, state regulators said.
A transfer pump at a tank battery in Mountrail County, in the state's northwest corner, failed, causing storage tanks to overflow, according to the North Dakota Department of Mineral Resources (DMR).
A state inspector has been sent to the scene to monitor remediation, DMR said.
Hess was not immediately available to comment.
(Reporting by Ernest Scheyder)