Not just any oil spill. The Keystone pipeline dumped notoriously hard-to-clean ‘dilbit’ in Kansas

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The spill in Kansas is now the second-largest spill of tar sands crude on U.S. soil. And scientists say this stuff comes with major complications for containing and cleaning it.

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.

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.”

One silver lining: The 2016 report suggests that although bitumen spills may harm water quality more than conventional crude oil spills, as the substance weathers, it may pose less risk of contaminating groundwater (as opposed to surface water such as creeks) and drinking water.

On Wednesday, the Kansas News Service asked TC Energy which specific detection techniques the company is using to verify whether the crude oil spilled in Kansas has been entirely contained within a four-mile stretch of Mill Creek.

The News Service also asked which specific cleanup techniques are being used to address the concerns of scientists that traditional crude oil cleanup approaches have limited success on diluted bitumen spills.

TC Energy wouldn’t offer specifics.

“We have the people, expertise, training and equipment to mount an effective response and clean-up, and that’s what we’re doing,” the company said in an email.

It repeated previous public statements that it has deployed booms at the site and said it sees “no indication” that the oil is passing its barriers.

“Our approach in any incident is to respond and clean up the site as quickly as possible,” it said, “reducing the opportunity for any type of crude oil, including diluted bitumen, to have a lasting impact on the environment.”

It also noted that its containment efforts were monitored by the EPA.

The EPA says the spill has been contained to the 4 miles of creek that lie downstream from the pipeline break, and that the spill didn’t affect drinking water supplies, including wells.

The agency has coordinators at the site to oversee the cleanup.

Two underflow dams have been built, but they allow the stream to keep flowing under the water’s surface, where dilbit could already be present.

In 2007, the U.S. Department of Transportation decided it would allow the stretch of Keystone pipeline that runs from Nebraska through Kansas to Oklahoma to eventually operate at a higher pressure than is otherwise allowed because it would be made of stronger steel. It gave the final go-ahead a decade later.

On Thursday, the EPA said workers had pulled about 5,600 barrels of fluid from Mill Creek, though that fluid is a combination of oil and water. It says 5,000 cubic yards of oil-contaminated soil have been removed, and nine cubic yards of oily solids.

Tar sands oil, or bitumen, is far too thick to travel through pipelines. So companies in Canada force it into a more moveable state by mixing it with lighter volatile compounds.

But if a pipe breaks and the oil escapes, the diluted bitumen soon reverts to its original, sludgier consistency. The additives largely evaporate, leaving the ultra sticky, thick bitumen residue.

Bitumen doesn’t float on water, the way crude oil does. And that leaves a short time to capture diluted bitumen from the surface of rivers, creeks and lakes before the sludge disappears from view.

“This situation is highly problematic for spill response,” the National Academies report concluded, because “there are few effective techniques for detection, containment, and recovery of oil” once it has begun sinking.

And once it reaches the bottom of the water body, finding and cleaning it remains complicated. Retrieving generally involves dredging.

“Given these greater levels of concern,” the report concluded, “spills of diluted bitumen should elicit unique, immediate actions.”

The scientists expressed concern that federal policies that govern spill planning and response fell short of properly considering the special conundrums posed by diluted bitumen.

“Broadly, regulations and agency practices do not take the unique properties of diluted bitumen into account, nor do they encourage effective planning for spills of diluted bitumen,” the report said.

Most methods for trying to detect sunken bitumen don’t seem to work well, the report said.

The cause of the pipeline break in Kansas remains unknown, and a third-party analysis of the matter could take up to three months, according to the U.S. Department of Transportation administration that regulates oil pipelines.

The Michigan spill involved upward of 840,000 gallons (20,000 barrels) of oil. That contaminated more than 30 miles of the Kalamazoo River, plus nearby woodlands and wetlands. The sheer scale of the disaster was exacerbated by heavy rains.

It took four years and more than $1.2 billion to retrieve as much of the oil as was deemed feasible. Some amount was left because getting at the sludge is itself so damaging to the affected ecosystems.

Thousands of animals coated in oil were caught, treated and released.

In Kansas, TC Energy has said one beaver has been caught and is being treated.

The EPA added Thursday morning that four dead mammals and 71 dead fish have been found. It says biologists from the Kansas Department of Wildlife and Parks are assessing injured and dead animals.

TC Energy has put its initial estimate of the Kansas spill at about 588,000 gallons.

The region saw some rain this week, but TC Energy says it built a second earthen underflow dam in recent days to brace the initial containment dam for the anticipated rain, and that containment remains successful.

Celia Llopis-Jepsen is the environment reporter for the Kansas News Service. You can follow her on Twitter @celia_LJ or email her at celia (at) kcur (dot) org.

The Kansas News Service is a collaboration of KCUR, Kansas Public Radio, KMUW and High Plains Public Radio focused on health, the social determinants of health and their connection to public policy.

Kansas News Service stories and photos may be republished by news media at no cost with proper attribution and a link to

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