Acting Capt. Joe Simmon walks past a Charleston Fire Department ladder truck Tuesday in the fire station where three of the nine fighters who were killed in a furniture warehouse fire where assigned in Charleston, S.C. Fire swept through the Sofa Super Store and warehouse, collapsing its roof Monday? and killing nine firefighters inside.

Charleston, S.C. ? Firefighters huddled in prayer Tuesday near tiny, white crosses in front of the smoldering remains of a furniture superstore where nine of their colleagues were killed. For some, it was all they could do – they were too raw to talk about the nation’s biggest loss of firefighters since Sept. 11.

There were other remembrances in town: Outside the fire station that was home to five of the men, a jacket and yellow fireman’s helmet were draped on a flagpole, a pair of firefighter’s boots at its base.

“I can’t say much without crying,” one firefighter in the 237-member department said in a station mess hall.

There was no indication the firefighters did anything wrong when they rushed into the burning warehouse, believing employees were trapped inside. “They did exactly what they were trained to do,” Fire Chief Rusty Thomas said.

But within moments, flames swept across the warehouse, blowing out windows and eventually collapsed the roof.

“I lost nine of my best friends,” said Thomas, choking back tears Tuesday. “To the families, you gave them to us, and we protected them as best as we could.”

The cause of the fire that ripped through the Sofa Super Store on Monday night was under investigation, though arson was not suspected. Through the night, firefighters, police officers and other rescue workers saluted as the firefighters’ bodies were carried from the twisted mass of brown steel.

Some firefighters 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 Tuesday, memorials appeared across this seaside city, still stunned by the tragic loss.

Firefighters draped an American flag over a sign near the front of the store and one shopping plaza posted a message of “God bless our Charleston firefighters” on its marquee.

The nine firefighters – all men – ranged in age from 27 to 56, with anywhere from 18 months to 32 years on the job. Officials said their bodies were found in various places around the gutted building.

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

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 literally burst into flames.

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

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

Officials said the fire started in a storage area of the store, a huge showroom and warehouse on a commercial strip of car dealerships and body shops locals refer to as the “Auto Mile.” The first emergency calls came in at about 7 p.m., and firefighters were told two employees were trapped.

Later Tuesday, however, 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 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, a corrugated-metal structure next to a gas station.