By the time it was out, three buildings with some 50 apartments had been damaged.
The Red Cross says it is providing assistance to some 75 to 80 people displaced by the fire.
Seven people had to be rescued, and one person was hurt. So far, there's no word on that person's condition.
The fire was declared under control just before 7:30 p.m.
There's no word yet on a cause.
Click here to get the latest Philadelphia news and headlines from across the Delaware and Lehigh valleys.