DENVER, Dec. 1 (UPI) -- The U.S. Environmental Protection Agency said Thursday a black substance leaking into a Denver creek contains cancer-causing benzene.
John Gallagher, vice president of refining at Suncor Energy, said he believes his company's plant is the source of the substance, The Denver Post reported.
No public health warnings have been issued so far.
Workers contracted by Suncor have been working since Monday to clean up what the EPA is describing as a "gasoline-like material," preventing it from reaching the South Platte River, a major source of drinking and agricultural water for northeast Colorado.
Sandbags, dams and booms have been placed in Sand Creek to stop the liquid from flowing into the river when forecast rain and snow raise the water level.
"We have secured any material from entering the creek. We're pretty happy with the process," Gallagher said. "Our job, No. 1, is still to make sure we keep the waterways protected."
The EPA told Suncor to conduct daily inspections along the creek, monitor groundwater contamination and clean up oil on the banks of Sand Creek and South Platte River by March.