SALT LAKE CITY -- Patches of Utah held underground tanks that fueled World War II military trucks. Whole ranges served as experiment stations for testing nerve gases or explosives.

Abandoned military sites like these have been a focus of the Army Corps of Engineers for two decades. Fifty-eight sites in Utah were deemed likely to hold bomb fragments, toxic waste and other worrisome wartime leftovers.

"Their focus was winning the war," said the Corps' Jerry Vincent, whose agency hosted a recent open house on the sites at Utah Department of Environmental Quality headquarters. "Now, our focus is cleaning up what they did."

The Corps gave a progress report last week on nearly three dozen sites in northern Utah.

Nine of the 58 abandoned sites in Utah have been fully cleared so far. State environmental officials have signed off on the Corps' conclusions.

Rik Ombach, who monitors the Corps' work for the state Division of Environmental Response and Remediation, said 10 more sites may soon have the "No DoD Action Indicated" stamp, meaning investigators found nothing to clean up.

They include three on Salt Lake City's East Bench: the Fort Douglas Toxic Exercise Area, the Red Butte Reservoir and an old aircraft display site located at the corner of Foothill Boulevard and Sunnyside Avenue.

Another no-action site is Camp Kearns, 5,643 acres used for up to 15,000 troops in World War II. The site is now used by the 2002 Olympic skating oval, homes and businesses.

"There wasn't anything left to be concerned about," Vincent said.

The Corps already has addressed some suspect sites. They include two trenches, the grave of more than 1,600 sheep that died in 1968 after an open-air nerve-gas test at Dugway Proving Ground went awry and the agent was spread beyond proving ground.

In 2000, the Corps determined there was no residual contamination at the site or on the sheep. They had the carcasses dug up five years ago and dumped in a Wendover landfill.

Some $3.4 billion has already been spent on the assessments and cleanups nationwide. Some estimate $20 billion more -- and perhaps a century -- will be needed to get the job done.

One Utah cleanup that has dragged on is a former testing ground for bombs and chemical weapons, about 23,085 acres associated with Yellow Jacket mine ranges. Used to test bombs to deal with Japanese soldiers who hid in hardened bunkers, the area was peppered with more than 2,900 bombs, rockets and mortars.

The devices, which contained phosgene, mustard gas, napalm, gasoline and other chemicals, were found at the site. Some were found unexploded in the mid-1980s.

The family that owns 1,425 acres affected sue the government unsuccessfully to get the site cleaned up.

The Corps has since scheduled the site for reinvestigation in 2007.