A tank leak caused 773 barrels, or 32,466 gallons, of brine to spill at a saltwater disposal well in Billings County, the North Dakota Oil and Gas Division said Monday.
Cypress Energy Partners reported the spill occurred June 22 about 9 miles north of Belfield.
About 20 barrels, or 840 gallons, of oil also spilled.
The contamination was contained within the diking on site and has been recovered, according to a spill report.
A state inspector will be on location this week to investigate the incident.