Spilled diluted bitumen complicates Keystone pipeline cleanup

The oil spilled from TC Energy Corp’s ruptured Keystone pipeline was diluted bitumen, the US Environmental Protection Agency (EPA) said on Thursday, adding complications to the cleanup.

The 622,000 barrels per day (bpd) pipeline was shut down last week after it spilled 14,000 barrels of oil in rural Kansas, including in a creek. Bitumen tends to sink in water, making it more difficult to collect than oils that float.

The sections of the pipeline that carry oil from Alberta to refineries in Illinois opened at reduced capacity on Wednesday. The ruptured section that stretches from south of Steele City, Nebraska, to a storage center in Cushing, Oklahoma, remains closed.

Bitumen from Canada’s oil sands is a dense, thick form of oil that shippers dilute with lighter oils so it can move through pipelines. The resulting product is called dilbit for short.

A 2016 National Academy of Sciences study for the US Department of Transportation examined whether transporting dilbit posed different environmental risks than other oils, following a 2010 spill in Michigan.

The report said that when diluted bitumen spills, a thick, dense material forms as a residue after exposure to the environment. The residue tends to stick to surfaces, and sometimes sinks to the bottom of a body of water.

“For this reason, spills of diluted bitumen present particular challenges when they reach water bodies,” the report states.

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Prolonged Keystone pipeline shutdown could affect western Canadian oil producers

Crews are using equipment to flush oily water from the surface of Mill Creek in Kansas and to siphon crude oil into trucks. Colder temperatures could hamper the cleanup, the EPA said.

Cleanup from the 2010 Enbridge Inc ( ENB.TO ) pipeline spill took years because of the difficulties in collecting dilbit, said Keith Brooks, campaign director at Environmental Defense, adding that recovery in Kansas may not be different.

“I would expect it to be a long, long time.”

The Sierra Club, another environmental advocacy group, questioned why parts of the pipeline reopened before TC Energy identified the cause of the leak.

“How can we be sure that other segments of the pipeline are not equally prone to failure?” said Zack Pistoria, Sierra’s lobbyist in Kansas.

More than 400 people are involved in the cleanup, including personnel from EPA, US Pipeline and Hazardous Materials Safety Administration, state and local agencies, TC Energy and TC Energy contractors, the agency said.

The response team has so far recovered 5,567 barrels of oil-water mixture from Mill Creek.

The EPA said four dead mammals were recovered, and 71 fish.

In a statement, TC said it excavated around the ruptured pipeline segment and called it a milestone in the repair and investigation process.

Enbridge, meanwhile, increased its rationing of space on its oil main for January, in a sign that demand for Canadian barrels heading south is outstripping pipeline capacity after the Keystone outage.