New Bedford, MA – By John Ellement, Boston Globe Staff

NEW BEDFORD — An off-duty firefighter saw a “solid blue” wall of flame, and another neighbor told of how the dark of night was transformed into an “orange sky.” A woman who lived on the first floor of the apartment building recalled fiery embers, a loud bang, and then the astonishing sight of its roof landing in the parking lot.

And then there was shouting. “It was absolute terror and pain,” Kevin L. Dubay said quietly as he described what he heard around 1 a.m. yesterday when the Collette Street apartment building where he lived exploded. The detonation not only blew off the roof of the 100-year-old building, but it sent the third floor crashing into the second and trapped a man inside the wreckage.

“It wasn’t a man screaming for help; it was a man screaming because he was being burnt to death,” the 24-year-old Dubay said. “Everybody who is standing out here would have loved to have gone back into the building for him. But it was impossible . . . The screams. That is something I will never forget in my entire life.”

Yesterday, authorities were trying to identify the man, whose body was removed with quiet respect by firefighters around 10 a.m. Authorities were awaiting confirmation of the victim’s identity from the state medical examiner’s office.

Authorities and NStar officials searched for the cause of the second massive explosion in this city since Nov. 22, when a home in the South End was blown apart, apparently when natural gas built up in the basement and detonated. Residents said they smelled gas yesterday, but no one reported it.

No one had been home at the South Second Street house in November, but at least nine people were inside 178 Collette St., a six-unit apartment building, early yesterday, including 31-year-old Debbie Leandre, her two children, her father, and stepbrother.

A first-floor resident for just two months, Leandre said she had returned home from her night shift factory job and was quietly moving around the apartment, trying not to awaken her 12-year-old son, Max; her 10-year-old daughter, Meghan; her father, James J. Leandre; and his stepson, 18-year-old Kevin Chor.

“There was a big bright light. Then I heard a bang,” said Debbie Leandre. “I thought at first that a car had hit the house. I went to look out my window, and then I saw the apartment, the house, falling into the yard.”

Debbie Leandre shouted warnings to her family, and they quickly reacted. James J. Leandre, a 53-year-old Yellow Cab dispatcher, said he quickly realized that they could not escape out the apartment’s rear door.

His stepson ran back to the kitchen at the opposite side of the apartment, opened a pantry window, and climbed outside. The children were then handed out the window; Debbie Leandre followed, and James Leandre went last after making sure all were safe

“It’s part of the job” of being a father, he said. Debbie Leandre, whose daughter turned 10 yesterday, was relieved that firefighters later found her chinchilla and a turtle alive. At midmorning, a firefighter also found one of her kittens, covered in soot but still alive.

As they stood watching firefighters, New Bedford police, and state troopers from the state fire marshal’s office search the charred wreckage for other possible victims and a cause for the explosion, Debbie Leandre turned to her father and talked about her future.

“I don’t know what I’m going to do, Dad,” Leandre said as her father draped a comforting arm around her shoulder. “Well, we’re going to get tough,” he said. “We’re tough anyway.”

One of the neighbors drawn by the noise, heat, and enormous flames to the densely packed street one block from the Sunbeam bakery was the city’s mayor, Frederick M. Kalisz Jr., who lives eight doors away on Collette Street.

Kalisz said he had fallen asleep in his living room when he heard the detonation. “I just walked out of my house, and it was right there. I could see fireballs coming out of the roof. “It was just a horrific sight,” he said. “I was speechless at the moment, trying to think of what I had to do.”

The mayor said he alerted his staff and then tried to make his way to the scene, but was unable to get close because the intense flames were shooting from the wrecked house, endangering adjacent houses, as well as those across the 50-foot-wide street. Arriving firefighters prevented the two-alarm fire from spreading.

Working with private landlords, Kalisz said the city was trying to arrange housing for those displaced by the fire and to help coordinate offers of help coming into City Hall.

The building has been owned since 1999 by Konrad St. Gelais of Acushnet, who purchased it for $179,000 that year, according to city records. St. Gelais, who owns real estate and auto insurance businesses, could not be reached for comment yesterday.

“[He’s] someone that does not maintain shoddy properties,” Kalisz said of St. Gelais.

Robert W. Thatcher, the city’s head of inspectional services and building inspectors, said the building was overdue for a city inspection of its common areas, something Thatcher said his office tries to complete every two years for rental housing in the city. He also said that no one had sought a construction permit for the property since 1998, one year before city records show St. Gelais bought the building. In that year, the previous owner installed a gas heater inside the first-floor apartment.

Dubay, who lived on the second floor, escaped with his 80-pound dog, Ajiah. He said everything he and his fiancee, Rochell T. Rogers, owned was lost in the fire.

But he held out hope that amid the rubble, firefighters would find a wedding ring he said he had bought recently for Rogers.