Crews were dispatched to the 4600 block of Patrician Boulevard at about 11:35 a.m.
Firefighters arrived to heavy smoke and flames from a fire on a third-floor balcony in the Limestone Terrace Apartments. The fire quickly spread and flames could be seen shooting through the roof.
Chopper 6, which flew over the building once the flames had been extinguished, showed a massive hole in the roof and smoke coming from the building.
One firefighter was taken to an area hospital with burns to the back of his neck, head and face from falling debris. At least one other person was being evaluated.
In total, 20 residents from the 12 units were displaced.
Eighty-five firefighters responded to the blaze, authorities said.