BISMARCK, N.D. – The North Dakota Department of Environmental Quality was recently notified of a produced water and crude oil spill resulting from tank overflows in Mountrail County. The tanks are located about 10 miles southeast of Stanley on a well pad operated by Stephens Williston LLC, doing business as Seg Williston LLC. The incident occurred on June 9 and was reported the same day.

Initial estimates indicate approximately 170 barrels (7,140 gallons) of produced water, and 170 barrels (7,140 gallons) of oil were released from the tank overflows. About 140 barrels (5,880 gallons) of produced water and oil impacted pastureland surrounding the location. Produced water is a by-product of oil and gas development.

Personnel from Environmental Quality are inspecting the site and will continue to monitor the investigation and remediation. Federal and state laws require operators to report the spillage of materials that may pollute water, air or soil. Visit spill.nd.gov for more information about North Dakota’s Unified Spill Reporting System notifications and the public access tool.