By Roger Alford
The Associated Press

CORBIN, Ky. - An explosion and fire at a southern Kentucky insulation factory Thursday injured more than 20 workers, some critically, and sent hundreds of nearby residents fleeing from a plume of black smoke that rose into an overcast sky.

"I didn't know how bad it was until I got outside and saw the smoke and the fire," said Helen Rutherford, 48, who has worked at the plant for 29 years. "What I saw today, I never want to see again."

Workers at CTA Acoustics who escaped injury pulled severely burned colleagues from the building to await the arrival of ambulances. Authorities initially warned that the smoke may have contained hazardous chemicals, creating a panic among residents, before retracting the statement later in the day.

Residents were allowed to return to their homes about 5 p.m. after firefighters extinguished the blaze.

The cause of the 7:30 a.m. explosion was not known. Investigators from several state and federal agencies, including the U.S. Chemical Safety and Hazard Investigation Board, arrived on Thursday to begin investigations.

Jim Tomaw, legal counsel for CTA in Corbin, said the fire began near a furnace where raw fiberglass is mixed with resin and molded into sheets. He said 150 of the company's 561 employees were in the plant.

"It was just like a tornado came through," said Rutherford, of London. "A big puff of wind blew all my paperwork into the floor. It just got black. I heard like a muffled boom."

Then workers were told to leave the building.

Elizabeth Ash, a spokeswoman for Madison Heights, Mich.-based CTA Acoustics, said 26 employees were injured.

Some were burned over 70 to 90 percent of their bodies.

"We prepare as physicians for disasters - I have never seen this," said Dr. George Liu, a general surgeon at Baptist Regional Medical Center in Corbin. "The best thing people can do is pray for these people."

The Corbin hospital said it treated 30 victims. While 10 were treated and released, several in critical condition were transferred to burn centers at the University of Kentucky Hospital in Lexington and Vanderbilt University Medical Center in Nashville, Tenn. Some victims had to travel to University Hospital in Louisville by ground ambulance because inclement, foggy weather prevented air transport.

Doctors at the University of Kentucky Hospital in Lexington told WDKY-TV that they were treating five men ranging in ages from 30 to 55 for third-degree burns. Four of the men were in critical condition and one was in serious condition Thursday.

"There will be several stages of recovery that will stretch over several months," said Dr. Brian Joseph, a plastic surgeon at UK.

Six victims remained in critical condition Thursday night at Vanderbilt, hospital spokesman Clinton Colmenares said.

There had been few violations at the plant, which had won a governor's safety award in 2001 after going three years and 4 million hours without a lost-time injury.

This month, the Kentucky Labor Cabinet proposed to cite CTA for a violation involving safety guards on machinery, said Eddie Jacobs, spokesman for the Kentucky Labor Cabinet. A routine conference on the proposed citation had been set for Thursday, but was postponed after the blast. The allegation arose from an employee complaint - the first ever received from a CTA employee, Jacobs said.

The company also was cited in 1989 and 1993 for serious violations - conditions that are not intentional but could cause injury or death. Those cases also dealt mainly with insufficient safety guards on machinery, according to agency records.

The company settled the citations for $5,600 in all. State inspections in 1998 and 2000 turned up no violations.

The plant in Laurel County near the Knox County line makes acoustical and thermal insulation products for the industrial and automotive industries. Tomaw said sales from the plant average $80 million to $90 million per year.

Bob Terrell, director of the Corbin Office of Economic Development, said the plant 90 miles south of Lexington supplies materials for Ford vehicles for heat and sound control.

Tomaw said the plant is undergoing a $100 million upgrade and renovation, but didn't believe that played any roll in the explosion and fire.

A spokeswoman for the Bureau of Alcohol, Tobacco and Firearms in Louisville said the federal agency was providing routine assistance to local authorities in investigating the explosion.

"At this point we're not aware of any criminal activity," said Laura Volk.

After Thursday's blast, authorities shut down a 13-mile stretch of nearby Interstate 75 for about an hour because of concerns that a large, black cloud of smoke coming from the plant contained hazardous chemicals.

Officials later said there was no danger to the public and reduced the area under an evacuation order. The fire continued to burn for hours, but had been mostly contained by early afternoon.

An employee and employees' relatives said small fires are relatively common at the plant, a contention that Tomaw acknowledged.

"It's endemic to the process - the material goes through a furnace," Tomaw said. "We may have one small fire a month or one small fire in six months."

Cindy Cravens, 24, had just gotten off work 30 minutes before the explosion. She said the plant has many fire extinguishers that employees use.

Tomaw said there was no indication whether such a fire was the trigger to Thursday's blast.

Roger Bales, 33, of Corbin, was working on a piece of equipment near where the explosion occurred. He escaped without injury.

"It happened so fast. I looked up, and I saw a big ball of fire coming at me," Bales said.

The AP's Charles Wolfe in Frankfort contributed to this report.