Pikes Peak Region Trail Finder

A worker vacuums contamination Thursday along the shore of Sand Creek where it meets the South Platte River north of downtown Denver. Craig F. Walker, The Denver Post

By Bruce Finley, The Denver Post

State health regulators on Thursday issued orders formalizing cleanup work already in progress to stanch the the flow of hazardous liquid seeping into Sand Creek and addressing newly identified contamination spreading underground from Suncor Energy's refinery to an adjacent Metro Wastewater plant.

U.S. Environmental Protection Agency cleanup coordinators determined that the black goo oozing from the bank of Sand Creek north of downtown Denver is "a gasoline-like material" that contains cancer-causing benzene. Highly toxic, benzene has been linked to leukemia, and federal authorities have determined that even minute amounts are harmful.

EPA lab test results released Thursday evening indicate benzene concentrations ranging from 2,000 parts per billion, where the liquid enters Sand Creek, to 480 ppb, where the creek enters the South Platte River — well above the 5 ppb national drinking-water standard.

"We don't want anybody drinking water in Sand Creek," EPA emergency response manager Curtis Kimbel said, adding that significant dilution occurs in the Platte.

No public health warnings have been issued.

Read about workers who strained in Thursday's snowstorm to clean up the gunk.