The fire left a dozen people with minor injuries, mostly related to smoke inhalation, said DeKalb County Fire Rescue Capt. Eric Jackson. He identified those hurt as four adults and eight children.
Jackson told WSB-TV that firefighters had to smash through doors to help some out.
Occupants inside were "literally dropping their children down to our firefighters and we were catching them, and that was before we put any water on the fire," Jackson told reporters.
"We had fire burning on one end of the building and residents on the other end didn't have a clue," he told reporters at the scene in an interview posted on the fire department's Instagram page. "So we were doing multiple things. We were catching babies; we were kicking in doors, letting folks know they needed to get out."
The fire had grown since fire crews first arrived but firefighters were gaining control of it, Jackson said.
"The fire had a little bit of a head start on us, unfortunately," Jackson said.
The cause wasn't immediately known.
The building, which includes about 20 units, is just northeast of Atlanta.
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