Investigators said Thursday the blaze was caused by a child playing with a lighter.
The fire on Manida Street was called in shortly after 2 p.m. on Wednesday, according to a fire official at the scene. It raged for two hours before crews were able to put it out.
Two firefighters were seriously injured and taken to the Cornell Burn Center, according to a fire department spokesman. Twelve others had minor injuries.
One civilian, a man in his 70s, was taken to Jacobi Hospital and is in critical condition, according to the spokesman.
Another person sustained serious injuries but is in stable condition and was evaluated at the scene.