The blaze was reported at 297 Monroe Street in the Bedford Stuyvesant section around 7:40 p.m.
Around 150 firefighters and EMTs arrived within two and a half minutes and were met by heavy smoke and flames around.
Officials say the age and deterioration of the buildings created a dangerous situation for firefighters.
Fire officials say that fire started on the second floor of the middle, four-story building on 283 Monroe Street, then spread to the adjacent buildings.
UPDATE: fire started on 2nd floor at 283 Monroe St. which is unoccupied, under renovation. Firefighter fell through a hole in floor but was able to pull himself out uninjured. Fire then moved up towards roof thru windows then to 2 adjacent buildings. Contd... https://t.co/XDW04XGw2F— CeFaan Kim (@CeFaanKim) January 12, 2021
The fire chief says the middle building is unoccupied and under renovation.
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It's also under investigation whether squatters were inside that building.
"It seems to us that the building was under renovation, FDNY Assistant Chief Jospeh Jardin said. "We had a firefighter initially upon entry fall through the floor. That's how we discovered it was compromised due to the renovation from a structural integrity perspective."
That firefighter was able to pull himself out of that hole uninjured.
The blaze then moved up to the third floor through the windows.
"There was a pretty significant collapse of the cornice," Jardin said. "The front part of the roof building you may see it not there anymore and came down."
One firefighter was treated on scene and taken to Cornell Medical Center with minor injuries.
The two adjacent buildings adjacent have families living inside.
It's unclear at this hour how many of them will be displaced Monday night.
The fire was placed under control around 10 p.m.
The cause of the fire is under investigation.
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