BISMARCK, N.D. (AP) — A 2015 pipeline spill of natural gas liquids in North Dakota initially reported as just 10 gallons (38 liters) could top 1 million gallons (3.8 million liters), a state regulator said Wednesday.
The North Dakota Department of Environmental Quality reported Tuesday that about 837,000 gallons (3.17 million liters) of natural gas liquids has been recovered from Oneok Partners' Garden Creek gas plant in western North Dakota.
Water Quality Division Director Karl Rockeman said about 90,000 gallons (340,677 liters) of contaminated groundwater also has been recovered at the plant near Watford City in the past four years.
"It certainly could be well over 1 million gallons at this point," Rockeman said of the severity of the spill.
Regulators never updated the public on the size of the spill, even as the Oklahoma-based company updated the state on cleanup. Last year, the company told the state it had recovered 240,000 gallons (908,498 liters) of the natural gas liquids.
Rockeman said a growing number of news reports in the past few weeks prompted the agency to provide better and timely updates, after criticism for disregarding its own policy in updating the volume of a pipeline spill
"We asked for updated numbers (from the company) because of the attention," Rockeman said.
The larger-than-publicized spill was first reported by DeSmog, a blog dedicated to fighting climate change misinformation. It cited an unnamed person who provided a document that said the spill could be as large as 11 million gallons (41.64 million liters).
Oneok has said that estimate was just "hypothetical assumptions" done by a consultant.
Rockeman said the natural gas liquids called condensate contain butane, propane and ethane. Wells have been drilled to reach the liquids, which have reached up to 30 feet (9 meters) underground.
The initial 2015 spill report said it "impacted areas" outside of the plant but regulators now say it had been contained within the factory's boundaries.
Most of the natural gas liquids that have been recovered have been "recycled and put back in the production stream," Rockeman said. The company also recently has begun using equipment to removed vapors locked underground, he said.
Rockeman did not know when the site will be cleaned up.
"It will be years," he said.