But within moments, flames swept across the warehouse, blowing out windows and eventually collapsing the roof in a twisted mass of brown steel. Nine men were killed in the nation's worst loss of firefighters since 9/11.

"I lost nine of my best friends," said Fire Chief Rusty Thomas, choking back tears yesterday. "To the families, you gave them to us, and we protected them as best as we could."

The cause of the fire Monday night at the Sofa Super Store, and exactly how the men were killed, was under investigation, but officials said arson was not suspected.

One fire captain said the men might have fallen victim to a flashover, in which superhot gases heat a building and its contents so intensely that they burst into flames.

Buildings that contain a lot of furniture are especially vulnerable, because the wood lacquer, polyurethane foam, and other combustible materials can reach flashover at a relatively low temperature - sometimes within minutes of a fire's outset.

Other officials said the roof collapse might have killed the firefighters.

Thomas said there was no indication his firefighters did anything wrong. "They did exactly what they were trained to do," the chief said.

The blaze plunged the city of 106,000 and its 237 surviving firefighters into mourning.

Through the night, firefighters, police officers, and other rescue workers saluted as the firefighters' bodies were carried from the smoldering ruins, with the last victim removed around daybreak.

Some firefighters wept. Some fell to their knees; others held their heads in their hands, or sat slumped on the bumpers of their fire trucks, their faces etched with grief and exhaustion.

Later in the day, as mourners left flowers outside fire stations and state officials ordered flags lowered, firefighters draped an American flag over a sign near the front of the store.

Officials said the fire started in a storage area of the Sofa Super Store, a huge showroom and warehouse on a commercial strip of car dealerships and body shops. The first emergency calls came in about 7 p.m., and firefighters were told two employees were trapped.

Later yesterday, the fire chief said only one employee was believed trapped. The employee made it out alive, Thomas said, but he said it was unclear whether firefighters had rescued him.

Firefighters searching for victims and trying to battle the fire picked their way amid rows of sofas and mattresses stacked five and six high on racks in the cavernous warehouse.

"It was burning everything," said Lesley Broughton, who lives in the neighborhood and works as a clerk at a convenience store near the gutted furniture store. "As fast as they would put out one side, another hot spot would pop up. Then glass started breaking and they told everybody to get back, and finally it was just an inferno."

Capt. Jeff Harrison said his firefighters were trying to knock down the flames when they apparently flashed over.

"To lose nine is just a tragedy of immense proportions," Mayor Joseph P. Riley Jr. said. "To lose nine is just unbelievable."

The building had no fire sprinklers and was not required to have them. The fire chief said sprinklers would not have put out the fire but would have at least slowed it.

It was the nation's largest loss of firefighters since the Sept. 11, 2001, attacks, which killed 340 firefighters. It was the deadliest fire in South Carolina since a 1979 blaze killed 11 people at a jail.

Officials identified the victims as Capt. William "Billy" Hutchinson, 48; Capt. Mike Benke, 49; Capt. Louis Mulkey, 34; Mark Kelsey, 40; Bradford "Brad" Baity, 37; Michael French, 27; James "Earl" Drayton, 56; Brandon Thompson, 27; and Melvin Champaign, 46. They had anywhere from 18 months to 32 years on the job.

President Bush said in a statement: "These firefighters were true heroes who demonstrated great skill and courage."

See a slide show on the Charleston fire via http://go.philly.com/scfire