Each day that passes, the hundreds of thousands of gallons of sludgy oil coating Mill Creek in north-central Kansas become harder to clean up.
That’s because the pipeline that busted just outside the town of Washington on Dec. 7 doesn’t carry conventional crude oil. It carries a product of the Canadian tar sands called diluted bitumen that changes dramatically in chemical composition and behavior soon after escaping from pipes.
A National Academies of Sciences study found that transformation means the crude oil can start sinking below the water’s surface in a matter of days.
The Kansas spill occurred eight days ago and is now the second-largest spill of tar sands crude on U.S. soil.
The Environmental Protection Agency acknowledged Thursday morning that the crude was diluted bitumen, also known as dilbit. But the agency wouldn’t respond to questions about the implications of that fact for cleaning and containing the notoriously elusive crude oil.
And it wouldn’t disclose what methods were being used to verify the material is truly contained, even as Mill Creek continues to flow downstream.
TC Energy won’t answer those questions either.
The same 2016 National Academies of Science study of diluted bitumen — a deep dive ordered by Congress in the wake of the nation’s largest inland spill of the stuff in Michigan in 2010 — found that bitumen’s peanut butter-like consistency poses special risks to the environment.
“When a significant fraction of the spilled crude oil” sinks below the water’s surface, the scientists concluded, “the response becomes more complex because there are few proven techniques in the responder ‘tool box’ for detection, containment, and recovery.”
Once it escapes its pipe, diluted bitumen also becomes far stickier than other types of crude oil.
In Michigan, the gunk proved so gluey that it was easier to haul rocks away that had been coated with it along the Kalamazoo River than to scrub the bitumen off of them, said Steve Hamilton, a biologist who advised the U.S. Environmental Protection Agency on the cleanup.
“It’s almost impossible to clean from surfaces,” said Hamilton, a professor at Michigan State University and member of the National Academies of Sciences committee that wrote the 2016 report on diluted bitumen. “We tried hot water sprays and detergent and so on. … It’s extremely sticky once it has been exposed to air for a while.”
Of the estimated 14,000 barrels that spilled — nearly 600,000 gallons — out of the three-foot-wide Keystone pipeline, most has not yet been recovered.
In the 2016 report, scientists concluded that once the bitumen starts sinking, detecting it and retrieving it becomes very difficult. So does containing it.
“It ultimately took four years to clean up the Kalamazoo River spill,” Hamilton said Wednesday, “And you could argue that three and three-quarters of those years were all about (removing) submerged oil.”
