(credit: CBS)

(credit: CBS)

DENVER (AP) – The underground flow of an oil-like substance near a creek in western Colorado has slowed, and officials say they are confident local water sources are not at risk. But much remains unknown, like where the liquid is coming from, what’s in it or when it started to ooze.

On March 8, workers from Williams, an energy company with a natural gas plant and several pipelines in Parachute, Colo., were evaluating the area in preparation for the installation of a new pipeline. In the process of excavating existing pipelines, workers encountered contaminated soil and immediately reported it to the Colorado Oil and Gas Conservation Commission, according to a spill report filed by Williams.

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The commission responded by asking Williams for a plan to clean up the affected soil, according to Todd Hartman, a spokesman for the state Department of Natural Resources, which oversees the commission. But on March 13, Hartman said, Williams notified the agency that the contamination was liquid hydrocarbons, essentially a lighter form of oil. That raised the level of alarm, and by the end of the week, industry and state officials decided to announce the leak publicly.

“When additional liquid hydrocarbons were discovered, at that point our field people were in contact with COGCC directors, because they believed this was a serious event,” Hartman said.

So far, operators have recovered 5,838 gallons of oil and 86,478 gallons of contaminated groundwater. The seepage covers a 200-by-170 foot area and is just 60 feet from Parachute Creek, which runs into the Colorado River.

About 50 people from Williams and state and federal regulatory agencies are at the site of the leak, company spokesman Tom Droege said. Booms have been placed across the creek, trenches have been dug next to the water, and workers test for hydrocarbons every 30 minutes.

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The Environmental Protection Agency is planning to issue an order to Williams requiring the company take action to protect the creek, but a spokesperson for the EPA said the agency determined there was no imminent threat, based on visual inspections and water samples.

Parachute Town Administrator Bob Knight toured the leak site Tuesday, along with the town’s mayor and public works director. After seeing the clean-up process, Knight said, officials are not worried about the water. Nor, he adds, are town residents, none of whom has contacted him to express concerns.

Parachute’s irrigation system draws from the creek, but based on recent weather conditions, Knight doesn’t expect irrigation to start until mid-April, and he believes the natural gas liquids will be gone by then.

That remains to be seen. Though the oozing has slowed, Droege said it is hard to say when the scene will be fully cleaned up, in part because no one knows where the liquid is coming from, or exactly which hydrocarbons are present.

Neither Droege nor Hartman could remember a similar instance in Colorado, where natural gas liquids were discovered underground and not as the result of a spill. Williams runs a number of pipelines through the area, some carrying natural gas and some carrying natural gas liquids, but Droege said it is unclear whether a pipeline is the source of the problem.

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