A smoldering heap of melted, twisted metal is all that's left of a 10-bay garage after a fire ravaged the structure outside Columbia on Thursday afternoon.

Nearly 100 firefighters responded to the blaze at River Valley Disposal, 100 Deascenti Drive. It was ruled accidental by a state police fire marshal who said it was started by workers welding in the building.

Firefighters on the scene said the blaze, which began around 12:45 p.m., probably reached temperatures as high as 2,000 degrees. It burned a host of combustible materials and machinery in the 200-by-400-foot garage, which housed numerous businesses and residential storage units.

"It was hot, it was large," said Columbia Consolidated Fire Chief Jason Rhoads.

When the first two trucks arrived around 1 p.m., Rhoads said, the wooden building was fully engulfed in flames and smoke, with small explosions, probably caused by oil, gas and tires in the garage.

The frame on the front of the building was collapsing when crews arrived, Rhoads said. Then the tin roof caved in, stopping firefighters from dousing the flames.

Rhoads said the location of the fire — far down a long lane in an isolated neighborhood off Columbia Pike — made it difficult to find water. Several tanker crews were called in to set up a water supply.

"All the water in the world wouldn't have helped anything with the building," Rhoads said.

As the sun set, fire crews watched while heavy machinery was used to separate the metal roof from the debris so firefighters could get water into the hot spots.

Several large mangled pieces of equipment, including a truck, a tow motor, fuel tanks and other machinery, were seen smoldering in the pile of metal.

By evening, the biggest concern for crews on the scene was potential runoff polluting Strickler Run, a small stream bordering the property.

Chuck Anderson, Columbia Borough Fire chief, said chemicals used in portable toilets on the property were mixing with water used to put out the fire. The chemical could be seen and smelled in the water.

Anderson said officials from the Department of Environmental Protection, Lancaster County Haz-Mat and Columbia Emergency Management Agency were monitoring the stream for pollution.

Rhoads said at least 12 companies were called to the scene, including Mount Joy, Marietta, Washington Boro, Maytown, West Hempfield, Highville, Mountville, Wrightsville and three from Columbia.

Three firefighters suffered minor injuries and were treated at the scene, Rhoads said.

Firefighters remarked that the blaze came one year to the day after a fatal fire in Columbia in which Parke Douglas Dicely, a 52-year-old candidate for borough council, was found dead in a second-floor bedroom in his home at 148 Church Ave.

River Valley Disposal, a trash disposal and recycling business owned by Bob Kline, had a note on its Web site saying the company will be operating on its regular schedule with no service interruptions.

Anderson said it could be some time before an estimate is available on damages because the property owners need to take inventory of items housed in the garage.

"It will be days until they clean this up, but at least they're in the right business — not to be smart," Anderson said.

E-mail: myoder@lnpnews.com