Four of his comrades and a city employee were pulled alive from the rubble, a fire official said.
The collapse of 300 W. Indiana Ave. in the city’s Fairhill neighborhood happened shortly before 3:30 a.m. — about 90 minutes after firefighters were called to battle the blaze there — and sent colleagues rushing to rescue those trapped inside, 1st Deputy Fire Marshal Craig Murphy said.
“Our department lost a member bravely fighting a fire and then caught in a building collapse after the fire was over,” he said.
“We just finished pulling … our brothers out of here. The next few weeks are going to be tough,” Murphy told reporters on Saturday morning.
Four firefighters and a municipal licensing and inspection worker were rescued and sent to hospital. The licensing officer was released and all four firefighters remained hospitalized Saturday morning in stable condition, Murphy said.
Williamson was “one of our most experienced lieutenants,” Fire Marshal Adam K. Thiel said during a briefing.
“I’m almost speechless,” Thiel said. “I haven’t finished crying.”
Officials identified the other five injured as Fire Marshal Lt. Sylvester Burton; Lt. Clarence Johnson; firefighter Dennis Daly; firefighter Robert Brennan, Jr.; and Thomas Rybakowski, supervisor of the city’s licensing and inspections department.
The Office of the Fire Marshal is investigating the cause of the fire with the assistance of the ATF, according to the statement. No cause has yet been determined, he added.
A search and rescue operation after a fire
Firefighters were called to the building at 1:53 a.m. to a box alarm and found a fire, which they put out, Murphy said.
As firefighters focused on displaced residents and “surveyed” — looking for remaining fires in hidden spaces — the building collapsed, Murphy said. Eight occupants of the property were safely evacuated, according to the city’s news release.
A person jumped from the second floor to avoid being trapped. Others were taken down systematically, Murphy said.
During rescue efforts, rescuers had a “dialogue” with those trapped, including tapping on the debris “so someone could tell someone was in there,” Murphy said.
Three firefighters and the inspector were initially trapped but rescued and taken to hospital, according to the press release.
It was a “lean-to/pancake collapse,” Murphy said, as some collapsed material could have fallen flat on a surface, other material could have leaned against a wall, creating from space. “There were a lot of empty spaces,” Murphy said.
Williamson was one of two fire department members who were trapped under debris after the collapse, according to the city’s news release. He was pronounced dead at the scene around 6:45 a.m., officials said.
The other member, Brennan, was taken to hospital and is in stable condition, the statement said.
The fire response for the building collapse was brought under control shortly after 7:10 a.m., he added.
CNN’s Michelle Watson and Paradise Afshar contributed to this report.