A small oil spill that hadn’t been fully cleaned up in northwest North Dakota has contaminated the Yellowstone River after the well site flooded, the North Dakota Department of Health reported Tuesday.

An oil sheen was detected on floodwaters of the Yellowstone River on Monday. Bill Suess, spill investigation program manager, said the oil originated on a Whiting Petroleum well pad in McKenzie County.

The sheen appears to be from residual oil associated with a spill that occurred on the well pad that had not yet been fully remediated, the department said.

Ashley McNamee, spokeswoman for Whiting, said the release occurred last week.

“We immediately recovered the majority of the 2 barrels of oil which was contained on location; however, we were unable to fully remediate the affected soil before the Yellowstone River began to rise,” McNamee said.

Suess said the health department was not aware of the original spill because it was contained to the well pad and less than 10 barrels and wasn’t required to be reported. State regulations do require all spills to be cleaned up, though there is no set timeframe required, Suess said.

The amount of oil detected on floodwaters is estimated to be no more than 1 barrel, or 42 gallons, according to Suess.

“It doesn’t take much to get a lot of sheen,” Suess said.

Now that the spill has impacted waters of the state, Suess said he expects Whiting will receive a notice of violation and potential fine for the incident.

The oil sheen has been contained by a boom and is being removed, McNamee said.

Personnel from the health department and the North Dakota Industrial Commission have inspected the site and will continue to monitor the investigation and remediation.

Companies with oil wells in the flooded area of northwest North Dakota have shut down their wells and pumped oil out of their tanks as a precaution, Suess said.

The river reached eight Whiting well pads, but the company has no leaks from equipment and the locations are contained, McNamee said.

“We will continue to monitor the level of the water and work with local and state officials to manage the situation,” she said.

Subscribe to Breaking News

* I understand and agree that registration on or use of this site constitutes agreement to its user agreement and privacy policy.

(Reach Amy Dalrymple at 701-250-8267 or Amy.Dalrymple@bismarcktribune.com)