BISMARCK, N.D. — The state Health Department says a lightning strike at a saltwater disposal facility in northwest North Dakota led to the release of more than 16,500 gallons of what is known as produced water.

Houston-based Oasis Petroleum Inc. reported the spill on Sunday at the site 15 miles northwest of Williston.

Produced water is a mixture of saltwater and oil that can contain drilling chemicals.

Health Department Water Quality Director Karl Rockeman says about 3,360 gallons of the oilfield wastewater escaped the site. He says the spill traveled about 1,000 feet from the facility but did not threaten any water sources.

Rockeman says crews were working to excavate contaminated soil at the site, under the supervision of a state inspector.