The fire at 665 New York Avenue in was first reported around 10:30 a.m. and quickly escalated to 7 alarms.
The fire was ruled under control by 2 p.m. Authorities believe a lightning strike started the fire.
Fire started on the roof of the 7-story building. Officials said the roof was collapsing onto the floor below.
More than 200 firefighters were on the scene, officials said.
At least 24 firefighters and 1 civilian suffered minor injuries. One of the firefighters said to be suffering from chest pains was in more serious condition.
24 firefighters hurt. One firefighter complained of chest pains at the scene and is in stable condition. The other 23 firefighters have minor injuries.
The Red Cross says 115 families have been displaced.