Crews dig up land at a saltwater-spill site outside Williston, N.D. on Jan. 12. PHOTO: ASSOCIATED PRESS
Salty wastewater from oil wells has contaminated a creek and flowed into the Missouri River after a huge pipeline leak in North Dakota, state officials said Thursday.
The state said the leak of 3 million gallons is its biggest-ever spill of “brine,” which in addition to high concentrations of salt often contains trace amounts of heavy metals that can be radioactive.
Such spills, which can kill vegetation and ruin farmland, have been increasing in Western North Dakota as the state has become a leading oil producer, pumping more than a million barrels of crude a day from the Bakken Shale.
Briny wastewater is extracted from deep underground along with oil and gas and must be disposed of, usually by injecting it back into the ground at separate wells drilled specifically for that purpose.
The state is investigating the cause of the leak, which doesn’t currently pose a threat to public health or drinking water, North Dakota officials said.
The area where the spill occurred is sparely populated and officials in surrounding Williams County said they weren’t concerned about the impact on water supplies, which are miles downstream from the area affected.
The Bakken region also is cleaning up from an unrelated oil spill over the weekend in the Yellowstone River, a tributary of the Missouri. An oil pipeline under the river burst, releasing about 960 barrels of crude near Glendive, Mont., and contaminating the local water-treatment plant.
In North Dakota, about 2.7 million gallons of wastewater have been collected from Blacktail Creek in a rural area about 15 miles north of Williston, N.D.
The cleanup effort has been complicated by winter weather that has made it more difficult to track the spread of the contamination and pump out the wastewater from the ice-covered creek, said Dave Glatt, chief of the state health department’s environmental section.
The wastewater leak was first detected two weeks ago when the Texas-based pipeline operator, privately held Summit Midstream Partners LLC, said that an “undermined amount” of brine had spilled out of the line, which was installed in June.
The company’s “full and undivided attention is focused on minimizing and remediating any environmental impacts, ensuring cleanup efforts, and addressing the needs of impacted landowners, regulators and government officials,” said Jonathan Morgan, a Summit spokesman.
The Summit Midstream pipeline collects water from 40 well pads and ships it to a disposal facility operated by a third party, the company said.
The state has faced a number of challenges handling the surge in wastewater, ranging from spills by tanker trucks and ruptured pipelines to storage tanks filled with the salty water that have been struck by lightning.
About 20,000 miles of gathering pipelines crisscross North Dakota, including those carrying wastewater to disposal sites, according to state data.
In 2013, North Dakota’s state legislature voted down a bill that would have required flow meters and pressure cutoff devices on wastewater pipelines. But state regulators have proposed tightening rules on the disposal of lightly radioactive well waste.
Write to Chester Dawson at chester.dawson@wsj.com
