Washington, KS- In the two months since the Keystone pipeline erupted in Washington County, Mill Creek has gone from being coated in floating oil nearly a foot deep, to a layer less than one inch.

About four miles of the creek remain shut off from the normal flow of water as part of the ongoing, round-the-clock cleanup.

Workers have pulled nearly 2 million gallons of oily water out of Mill Creek, carrying on in freezing temperatures by breaking and melting ice.

In mid-December, the Environmental Protection Agency says, about 1.5 miles of the stream were coated bank-to-bank in floating oil that pooled more than 10 inches deep in some places.

By Jan. 25, less than one-tenth of a mile remained coated bank-to-bank in floating oil that had dropped to less than one inch deep.

Now, no areas of the creek remain coated bank-to-bank, the federal agency says, though workers are still recovering oil.

Since workers bypassed about four miles of Mill Creek to help with the cleanup and stop chemicals and bitumen from washing downstream, part of the isolated stream now has little water left and workers are pulling ice and sediment from the creek bed and banks, the EPA says.

The agency says oil company TC Energy and state environmental officials have taken samples from drinking water wells near the spill site, but tests haven’t turned up any chemicals from the spill.

Springtime brings heavier rains to the area, and landowners worry about the risk that hard rains could cause the creek to overflow its banks.

The EPA says workers built a spillway in case of flooding. The National Weather Service provides daily input. And two weeks ago, TC Energy began work to increase the pumping capacity for diverting water.

Contaminated water

The nearly 2 million gallons of fluid pulled out of Mill Creek so far go into huge tanks or treatment ponds to separate the water and oil before transporting the oil to a refinery.

Workers inject air into the contaminated water to help vaporize some of the remaining chemicals. They also treat the water with granular activated carbon, the Kansas Department of Health and Environment says.

Next, samples of the treated water will go to a lab for analysis to determine whether workers can pour the water back into the creek downstream from the cleanup site.

“If not, the water will be re-treated until all contaminants are removed,” said KDHE, which oversees water treatment and discharge.

The EPA says construction is ongoing for a large water treatment system, including 5 acres of pond or ponds for the contaminated surface water. It says the ponds will be more efficient than the tanks now that most of the oil has been pulled from Mill Creek.

TC Energy says crews have recovered about 90% of the spilled oil. It has deleted from its website a counter that showed updates on how many barrels have been recovered.

Soil to Nebraska

A Nebraska landfill agreed to take the contaminated soil from the Keystone oil spill.

Trucks began hauling away the topsoil on Jan. 17 from the site in Washington County where the Keystone ruptured on Dec. 7 and sprayed extra sticky tar sands oil called diluted bitumen, or dilbit, onto several acres of prairie, cropland and Mill Creek.

“Laboratory analysis of the oil and waste defined it as not being hazardous,” KDHE said in an email.

A Shawnee County landfill north of Topeka, Rolling Meadows, had previously been named as a potential destination for waste from the oil spill.

“Landfills have discretion on whether or not they wish to receive waste,” KDHE said. “Pheasant Point Landfill (near Omaha) accepted the waste.”

In addition to the contaminated soil, Pheasant Point will take other waste from the site, such as oily protective clothing and absorbent pads, and floating booms used to block the oil slick on the surface of Mill Creek.

Cleanup costs and corporate donations

Separately, the Canadian company behind the oil spill will donate $60,000 to Washington County Hospital as part of a campaign it launched after the incident to match donations from the public.

TC Energy has also said it would give $7,500 to equip local emergency responders with better mobile and radio equipment.

TC Energy reported an annual revenue of nearly $10 billion and a net income of more than $1.5 billion in its most recent yearly report.

Last week the company estimated that cleaning up and investigating the Keystone spill will cost $480 million, and said it has “appropriate insurance coverage.”

The company is still investigating why the pipeline erupted, but has so far said that “bending stress on the pipe and a weld flaw” played a role.

Read more about the Keystone spill in Kansas:

• After Keystone oil spill, Kansas Democrats want to cancel tax exemptions when pipelines leak
• Keystone pipeline operator says faulty welding and other problems led to the Kansas oil spill
• Two months after the Keystone’s biggest oil spill, residents of a Kansas county wonder what’s next
• Crews have cleaned up most of the oil that spilled out of the Keystone
• The Keystone operator must repay some — not all — of the tax dollars spent on its Kansas oil spill
• Crews divert Kansas creek in the race to clean Keystone pipeline spill and prevent further pollution
• The Keystone pipeline is back in business while the Kansas oil spill cleanup continues
• Pipeline company says Kansas oil spill contained, but chemicals found downstream
• Not just any oil spill. The Keystone pipeline dumped notoriously hard-to-clean ‘dilbit’ in Kansas
• Keystone Pipeline has history of spills, warnings and fines. This Kansas spill is the largest yet

Celia Llopis-Jepsen covers the environment 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.

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