It started in a unit on the top floor of a seven-story building in Flushing late Saturday night.
Flames quickly spread to two adjoining units through a small attic.
Firefigheters had to get up on the roof in order to contain the flames.
The four-alarm fire was brought under control just after midnight.
Two people, including a firefighter, were treated for minor injuries at the scene, while a third person was hospitalized with smoke inhalation.
In all, 138 firefighters and 38 pieces of fire apparatus responded to the scene.
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