A “highly respected” 27-year Philadelphia Fire Department veteran died Saturday after the building he and his fellow firefighters were trying to save collapsed and trapped him in the heap of rubble, devastating the department and leaving a Fairhill neighborhood shaken.

The collapse that killed Lt. Sean Williamson, 51, occurred not long after the fire at the building housing a pizza shop in the 300 block of Indiana Avenue had been declared under control, around 3 a.m., officials said. Two other firefighters were hospitalized in critical but stable condition. In all, four firefighters and an inspector for the Department of Licenses and Inspections suffered injuries.

“This collapse occurred very quickly, with almost no warning,” Fire Commissioner Adam K. Thiel said at a late-day briefing.

“I’m almost speechless,” said Thiel. Describing Williamson as a retired Marine who was “highly respected throughout the department,” he said, “I’m not done crying.”

The shop evidently had undergone construction without permits in recent years, officials said.

Earlier in the day at a media briefing near the collapse site, an emotional Deputy Fire Commissioner Craig Murphy said: “It’s going to be a rough several weeks.”

The mayor’s office gave the following account:

Fire crews were called to the scene shortly before 2 a.m. Eight people were evacuated safely. The blaze was declared under control in about an hour, but the building collapsed shortly after 3 a.m. while firefighters still were at the scene.

The rescued firefighters and the inspector were taken to Temple University Hospital, where firefighters Robert Brennan Jr. and Dennis Daly were listed in critical but stable condition. The inspector, Thomas Rybakowski, and firefighters Lt. Clarence Johnson and Lt. Sylvester Burton were treated at the hospital and released.

Williamson, who was pronounced dead at the scene at 6:45 a.m., “was obviously the most severely trapped and difficult to access,” Thiel said.

He said that it was standard procedure for firefighters to remain at a scene after a fire is declared under control and that in this case firefighters and the L&I inspector were “assessing the structural stability of the building.” The reality, he said, in a city with aging structures, “Building collapses are something we’ve become accustomed to.”

Murphy said that the collapse followed what appeared to be a “pretty routine” box fire. He said the five who survived escaped at different times, one of them jumping from the second story of the building.

“You can’t predict this,” Murphy said. “This was just a catastrophic accident that has really hurt our department.”

The circumstances were similar to those involving the death of Lt. Matthew LeTourneau, who died on Jan. 6, 2018, while battling a fire in a rowhouse on the 2200 block of North Colorado Street in North Philadelphia. The second floor collapsed and LeTourneau was trapped. When firefighters and paramedics reached him about 30 minutes later, he was dead.

Neighbors said Star Pizza & Seafood had opened at the three-story corner property at Third Street and West Indiana Avenue five months ago.

Half a block from the collapse, Wanda Rivera was awake watching TV shortly before 2 a.m. when she heard sirens and trucks.

“At first it was just a lot of smoke so we thought there was a fire,” Rivera said. “They put out the fire then we saw the firemen leaving. Then they came rushing back again.”

Fire dispatch audio indicates most of the flames had been put out by 2:15 a.m. Over the next hour, engines tended to reports of other blazes across the city while a handful of firefighters remained at the Indiana Street fire scene with a building inspector. Around 3:25 a.m., a commander blared across the radio: “Emergency. Three-story collapse. Members inside.”

Fire engines and medics rushed back to the scene, where they found the smoldering building had collapsed like a pancake. One by one they identified survivors in the debris — whisking them off to area hospitals for treatment with reports of severe back pain, abdominal pain, leg pain — but the search for the fifth firefighter would carry into the hours after dawn.

By 7 a.m., first responders blanketed the blocks around Third Street and Indiana, where dozens of firefighters, police, and paramedics stood in a near-motionless crowd after hours of sifting through the rubble. The smell of burned wood lingered in the morning air.

At 7:19, the mass of firefighters slowly dispersed from the rubble, downcast and wiping away tears as they exchanged hugs. Few words were said as the rescue effort appeared to have come to a tragic conclusion.

Patricia Sermarini rushed to the scene when she saw the alert on the Citizens app about the collapse and the trapped first responders.

She said her son-in-law, a firefighter, was on the morning shift. As she pushed her way toward the edge of the taped-off scene on American Street, she said all she could think was, “I just need to see him.”

Relief swept through her when she saw him approaching from the site of the collapse. She said he had been on the scene helping with the rescue effort — but he had not been injured in the collapse. He was filthy with soot and dust, she said, and she hugged him immediately.

Moments later, Sermarini said she saw firefighters pull a body from the rubble.

”It’s so terrible,” she said. “This is so hard for them. They just want to get home to their families.”

The building had a pizza parlor on the first floor and apartments above. Property records indicate the property had been sold in September 2021 for $120,000, months before Star Pizza & Seafood opened its doors.

The owner of Star Pizza & Seafood — listed as Khalil Al-Ashraf in property records — could not immediately be reached for comment.

City records indicate no permits have been issued for construction and electrical work for the property in years. Yet photos from a recent real estate listing show a new electrical panel on the exterior wall along Third Street, as well as a metal staircase leading to an addition on the second floor — none of which appear in Google Street View photos of the building taken in 2019.

Records further indicate the property does not have active rental permits despite the apartments upstairs. Fire officials did not say if there were tenants living on the upper floors at the time of the fire.

City building inspectors also cited the property for numerous violations in May 2019, flagging issues with the kitchen hood, fire extinguishers, smoke alarms, and open junction boxes. Those violations were listed as outstanding in city records again in June 2021.

Since the 2019 inspection, the city has lost a third of its building inspectors, even as concerns about dangerous building conditions and shoddy construction practices have increased. Unlicensed rental units and unsanctioned construction have been endemic since long before the staff exodus.

Neighbors said Lucky Garden Chinese restaurant had operated at the building for about 12 years prior to the takeout pizza and seafood restaurant.

Herman Soto, Wanda Rivera’s husband, said Star Pizza had a good reputation among neighbors. “It was really good pizza,” Soto said. “The owners are nice people.”

Xavier “Sabi” Rivera said his parents used to own the building where they ran a pool hall and arcade in the mid-1990s.

Rivera remarked that a longtime metal staircase on the side of the building that residents used to access the upper floor had been removed during renovations, but he did not give a timeframe.

Thiel said the fire marshal would be back on the scene in the morning.

Said Mayor Jim Kenney: “This is a heartbreaking day for our city.”