The victims in this former mill city about 25 miles northwest of Boston were all found in units on the top floor of the building, which had a liquor store on the ground floor and apartments on the upper floors, fire officials said. Nine people were hospitalized with injuries not considered life threatening.
The cause of the fire is being investigated. State Fire Marshal Stephen Coan said authorities are looking into witness reports that the blaze was preceded by an explosion that sounded like fireworks.
Sar Soth, 43, escaped from a third-floor apartment along with her two stepchildren and two adults by climbing through a window and then down a firefighters' ladder. She said she had been having trouble sleeping when she heard a loud boom, saw fire outside a window and started screaming for the others to wake.
Her stepdaughter, Soriha Proeung, 11, said she yelled for firefighters to bring the ladder to their window.
"We all felt like in five minutes we were going to die," Proeung said. "I couldn't see. My eyes, my chest burned ... I just wanted to get saved."
Randy Perry, who lives in a building next door, said he looked out his window at 4 a.m. and saw people gathered outside the building as it was consumed by flames.
"I was shocked at how fast the fire moved from one end of the building to the other," he said.
Authorities say 48 people lived in the building, which sustained heavy damage. The roof entirely burned away, with the outer walls charred and the siding melted. Firefighters had to evacuate at one point as the roof gave way.
Neighbor Sarin Chun said she awoke to screams and saw someone hand a child out a window to another person on the street.
Witnesses said tenants jumped out of windows.
A police officer on routine patrol was the first to report the fire, while several tenants ran about 100 yards down the street to a fire station to sound the alarm, Fire Chief Edward Pitta said. But the building was fully involved by the time firefighters arrived.
Middlesex District Attorney Marian Ryan said she is "deeply concerned" by reports from witnesses that no fire alarms sounded. The building did not have a sprinkler system but was not required to, Pitta said. It did have an alarm system, and whether that was working will be part of the investigation.
"It's a tragic day for the city of Lowell," Mayor Rodney Elliott said.
The Red Cross is assisting displaced tenants, and the city is accepting donations of clothing and other essentials, Elliott said. A relief fund has been set up at the Jeanne D'Arc Credit Union in the city.
A chaplain for the fire department, Rev. Paul Clifford, said chaplains were offering what comfort they could to people who escaped.
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