WILLISTON – A well equipment malfunction caused the spill of about 20,874 gallons of produced water at a site about seven miles from Williston on Wednesday, according to a news release from the North Dakota Department of Environmental Quality.

Grayson Mills Operating estimated about 126 gallons of produced water impacted rangeland.

Produced water, also known as brine or saltwater, is a byproduct of oil production.

Personnel from the department will monitor the investigation and remediation.