GLENWOOD SPRINGS, Colo. (AP) _ A propane gas tank exploded in a gas company repair garage today, and at least two people were killed and 10 people were unaccounted for, a company vice president said.

Only one wall of the two-story building remained standing. ''It's all the way to the ground,'' said State Patrol Trooper Gary Eshelman.

Les Sitter, vice president of Rocky Mountain Natural Gas Co., said two bodies had been recovered and firefighters were searching the rubble of the two-story building for 10 other people who may have been trapped.

''We understand now it was a small, 1,000-gallon propane tank with just a small amount of propane in it. It was on a flatbed truck,'' Sitter said. ''Apparently it had just been pulled into a mechanical maintenance area. We don't know what the ignition was, but that was the source of the explosion.''

The explosion occurred at Rocky Mountain Natural Gas' operations office in this city about 150 miles west of Denver. The company, which has its headquarters in Denver, provides natural gas to west-central Colorado mountain communities.

Sitter estimated 30 people were working in the company's billing and repair departments at the time.

Thirteen people were taken to Valley View Hospital for treatment, said spokeswoman Catherine Evans. She said most were treated in the emergency room but did not discuss their injuries.

Fire departments from throughout Garfield County and cranes and heavy equipment from a highway construction project were sent to the site, in an industrial park in the western part of this Rocky Mountains resort city of 5,000 people.