Denver (AP) — State health officials on Thursday ordered Suncor Energy to immediately begin testing the air inside the Denver Metro Wastewater Treatment Plant to ensure worker safety near where a gasoline-like substance from the company's refinery was detected seeping into Sand Creek earlier this week.
Suncor Energy Inc. must test the air for the known carcinogen benzene, as well as suspected carcinogens and other chemicals, and install a ventilation system if high levels are found, according to the order. Suncor must also step up water sampling in the creek and set up a system to recover any petroleum seeping into the creek by Dec. 31.
Any signs of the seep, including staining on soil and vegetation, must be cleaned by March 1.
Suncor's vice president of refining, John Gallagher, said a crew of about 60 working around-the-clock has stopped the material from getting into the creek and workers were digging a trench as part of a recovery system. He said the department's order was expected.
"We're working to make things right," he said.
Water quality test results were expected Friday, said Environmental Protection Agency spokesman Matthew Allen said. Gasoline contains known and suspected carcinogens, and exact levels detected in the water were not immediately available, EPA incident commander Curtis Kimbel said.
State health officials referred water quality questions to the EPA. Health department spokesman Warren Smith said utilities nearby along the South Platte River that include Aurora and Thornton have been notified about the seepage.
Aurora Water spokesman Greg Baker said the utility last used water from the river in October and is not currently doing any testing. City of Thornton Water's Mark Koleber said lakes downstream from the seepage are fed by a ditch upstream from the creek and aren't affected.
Crews overnight worked on constructing a trench to contain the seepage along a 90- to 100-foot stretch of creek bank, Kimbel said.
"We're not going to stop until we're sure all of the material is contained and nothing is getting into the creek," he said.
Gallagher said crews worked through a snowstorm Thursday to shore up sandbag dams and booms in the creek to handle expected higher water from the storm.
The refinery produces jet fuel, gasoline, diesel fuel, and asphalt, mostly from oil from Colorado and Wyoming, Gallagher said. About 10 to 15 percent of the oil refined there comes from oil sands from Canada, he said, adding that the refinery has been there since 1938 and was designed to handle local crude. The Calgary, Canada-based company has three refineries in Canada and in Commerce City.
State health officials have long known about pools of oil in the ground from the 1980s and 1990s when it was owned by other companies, but the seepage is suspected of being caused by a fresh spill. Petroleum contamination levels in monitoring wells began to rise last year, and in October, the state ordered the company to do more to contain the contamination.
Health department Hazardous Waste Action Unit Supervisor Walter Avramenko said they suspect a fresh spill because the existing pools of oil had become more tar-like and stable through years of remediation and less likely to move off the refinery grounds. Avramenko said they're investigating whether a leaking pipe reported this summer on a pipeline between the refinery and a storage tank is the cause.
The concern is the amount of liquid that may be in the ground that would be enough to cause migration of thousands of feet from the source to the creek, Avramenko said.
Gallagher noted the historical contamination and said it's too early to tie any one event to the seepage.
"We don't have any obvious thing that we're looking at," he said.