Explosion Rocks Factory Outside Philly

Updated at 5:20 p.m. ET

A series of explosions at a welding supply company in suburban Philadelphia on Wednesday injured three people, forced evacuations and sent thick black smoke billowing over the area.

Delaware County Emergency Services Director Ed Truitt told The Associated Press that officials on the scene reported the civilians were taken to hospitals with burns.

Bernice Ho, a spokeswoman for nearby Mercy Fitzgerald Hospital, said three people were taken there for treatment and two were already released while a third was still being evaluated.

The explosions at Scully Welding Supply in Collingdale happened around 1 p.m. in an industrial area about seven miles southwest of Philadelphia, Truitt said. Nearly three hours after the first explosion, firefighters were still pumping water onto the fire.

Truitt said officials were concerned about the danger the flames posed to a nearby oxygen supply company.

"If that building were to be breached, that could make life real interesting down there," he said.

Tammy Scanlon, 38, who lives a few hundred yards across the railroad tracks from Scully's Propane, heard the explosions go on for about 30 minutes.

"It sounded like a car backfired the first time. It got worse," she said. "You could feel the dishes shaking in my house. It was just one after another."

Emergency officials are waiting for company officials to provide a headcount of who was in the building, Truitt said. A call to Scully Welding Supply rang unanswered.

Broadcast footage shows firefighters dousing flames between a pair of large tanks and debris littering the area between the tanks and nearby buildings. Black smoke poured from the blazes as firefighters shot water at flames from afar.

Kimberly Bench, 47, said she felt the air suck in and out of her house and looked up to see a big piece of metal hurtling skyward during the blasts.

"We heard a big explosion. Our house rattled," she said.

Butch Cook, who manages a nearby a sandwich shop, said he heard a series of explosions, each one followed by flames, for about 20 minutes.

"You would hear a bang, and then the flames would be there," the 54-year-old Cook said.

Truitt said a hazardous materials team was dispatched to the scene and police put out a countywide call for assistance to help with evacuations and crowd control. Buildings a quarter-mile in all directions were evacuated, he said.

CBS News Station KYW-TV in Philadelphia reports that Scully Welding Supply Corporation was founded in 1947 and specializes in supplying industrial and specialty gases, welding, industrial and safety equipment.