DENVER (AP) -- More spills were revealed Friday in a Colorado oil field swamped by floodwaters as cleanup efforts remained stalled due to high waters and regulators cautioned that more oil releases were likely to be found in coming days.
The latest spills include 2,400 gallons of oil spilled from a group of storage tanks, about 900 gallons from an oil tank that floated away and at least two others from damaged storage tanks that involved unknown volumes.
That brings the known volume of oil released since massive flooding began last week along Colorado's Front Range to at least an estimated 22,060 gallons. That's about 525 barrels.
Most of the oil releases reported to date came from storage tanks or tank farms operated by Anadarko Petroleum Co. near the South Platte River or its tributaries.
The Texas company is just one of many working in northern Colorado's booming Wattenberg oil field, raising the prospect that other companies have suffered similar problems since flooding began last week but have not yet been able to assess their damages.
An aerial survey of the flood area Thursday revealed up to two dozen overturned oil storage tanks, said officials with the Colorado Oil and Gas Conservation Commission. Releases from those tanks could not be immediately confirmed.
Also unknown yet is whether any pipelines have leaked.
With many roads in the area washed out, the spill sites remained largely inaccessible, preventing cleanup work from getting underway until water levels drop, said Anadarko spokesman John Christiansen.
"We've got a couple of amphibious vehicles and flat-bottom boats that we're using, but really until things have a chance to dry out and some of the infrastructure issues are sorted out, it's going to be difficult," Christiansen said.
The company has said it will clean up as much spilled oil as possible. Anadarko workers earlier in the week used absorbent boom in an attempt to minimize the release from one storage tank site Milliken, but were unable to stop the oil feeding into the South Platte.
A spokesman for Encana Corp. said personnel had examined the Calgary-based company's 484 oil storage tank batteries and found only two minor spills in which oil did not leave the site.
State officials say much of the oil has been carried at least some distance by floodwaters, meaning recovering it could be difficult or impossible. And wherever oil is found, regulators will face the challenge of figuring out where it came from and who should be responsible for cleaning it up.
Authorities in Weld County have said their concern over spilled oil is eclipsed by much greater volumes of sewage and other contaminants washing into local waterways.
Inspectors from the state and the U.S. Environmental Protection Agency planned further reconnaissance work over the weekend to look for additional spills. More finds were anticipated.
Besides Anadarko's storage tank spills, the state oil commission has tallied 11 minor spills. Those were described by the agency as sheens of oil coming off pieces of equipment.