Citizen app video showed heavy smoke and flames shooting from an apartment building in Clinton Hill.
It happened around 2:30 p.m. on Tuesday at 490 Myrtle Ave. between Ryerson and Hall streets.
The FDNY said the fire was contained to the roof of the building, which has a Key Food Supermarket on the ground floor and six apartment floors above.
The FDNY said about 120 fire and EMS personnel responded to the scene. The department said the day’s heat played a role in the response.
“In this type of weather, intense heat always plays a role,” said Assistant Chief William Ventura. “It slows down our responses because it takes more time to get people into position because the heat just slows us down a little bit, and we want to take a little bit more time to be safe.”
Tenants appeared to be let back into the building around 4 p.m.
The FDNY said no one was hurt.