Overflowing tanks released nearly 40,000 gallons of oil and brine northwest of Williston, ND, on Wednesday, state officials said.
Oasis Petroleum reported 490 barrels of oil and 455 barrels of produced water brine, or saltwater, released about 11 miles northwest of Williston, said North Dakota Department of Health officials. Crews have recovered 487 barrels of oil and 454 barrels of brine.
Most of the spill remained contained to the site, but some of the contamination extended to about 50 feet beyond the site, said Karl Rockeman, director of the Division of Water Quality. The spill did not affect any waterways.
Health department officials and North Dakota Oil and Gas Division personnel are responding.
Just last week, North Dakota suffered the largest spill since the state’s oil boom began, when almost 3 million gallons, or 41,728 barrels, of saltwater generated by oil drilling leaked from a pipeline, state officials said.
This leak is nearly three times worse than the worst previous spill. Two creeks suffered from the leak, but the full environmental effect might not be clear for months, officials said.