A company cleaning up a pipeline leak at a Oneok natural gas processing plant in McKenzie County has recovered 846,000 gallons of fluid, more than three times an earlier volume reported to the North Dakota Department of Environmental Quality.
The updated total reflects fluid recovered through July at the Garden Creek processing facility, where the spill was discovered in 2015.
Oneok provided the previous estimate of 240,000 gallons to the state last year. That figure accounts for cleanup efforts in 2017 only, said Karl Rockeman, director of the department’s Division of Water Quality.
Environmental Quality has faced criticism for not providing an update on the incident over the past four years, following news reports last month that brought to light the large magnitude of the spill. The leak was initially reported as 10 gallons of natural gas condensate with an "unknown volume" saturating the ground around the pipeline.
Condensate is made up of substances like ethane, propane and butane separated from methane after natural gas is extracted from the earth. It's part of the 846,000 gallons of fluid Oneok has recovered, with groundwater making up the rest. Rockeman said the state does not know how much of that volume is condensate.
“We asked the company if they can get more precise on that,” he said. “That is something they’re working on.”
The company is pumping out fluid from a series of wells put in place to reach the condensate 20 to 30 feet underground. This fall, Oneok plans to start recovering vapor that’s trapped amid the soil, Rockeman said. Given differences in pressure and temperature, condensate can exist in either liquid or gas form.
Rockeman said the company also will rely on wells to recover the vapor and use separate equipment that functions like a vacuum to remove the gas.
Oneok has consulted with the engineering firm AECOM on cleanup and is looking to hire a full-time employee to oversee the remediation effort, according to an Aug. 23 update listed on the incident’s spill report maintained by Environmental Quality.
The company did not immediately respond to a request for comment Tuesday.
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It’s unclear how long it will take to remediate the site.
“We’re not at any point where we’re done in the next year or two,” Rockeman said. “We will be at this for years yet.”
He said the company has been “very responsive” in taking action to clean up the spill.
“Looking at the volumes recovered, I think it’s been successful so far,” he said. “Obviously, there’s a ways to go.”
He said groundwater monitors placed around the facility do not show that any contamination has migrated off-site.
As details about the spill have emerged over the past month, Environmental Quality has been under scrutiny for the way it provides updates on oilfield-related spills. The agency maintains several publicly accessible databases of such incidents.
The environmentally focused DeSmog blog first reported on the Garden Creek spill last month, prompted by a leaked memo prepared by a consultant working on cleanup of the site. The memo provided an estimate that 11 million gallons had spilled.
State officials dispute that the true amount is that high. The company has said it’s impossible to determine the volume released. A spokesman said last month that the figures contained in the memo were “hypothetical assumptions” used as a basis for the design of equipment to clean up the site.
For years, environmentalists and some landowners have wanted the state to do a better job providing updates on oilfield-related spills. Environmental Quality has been planning to update its spill reporting system, and Rockeman said the agency intends to make those changes within the next year.