Chopper7 was over the scene of the fire around 3:45 p.m. in the 2500 block of North Luna Avenue, in the Belmont Cragin neighborhood.
A mayday response was initially declared, the Chicago Fire Department said. That call signaled a firefighter was in danger and needed help, but was canceled shortly after it went out.
A Chicago Fire Department spokesperson wasn't able to say the reason for the call, but officials said no injuries were reported.
The fire has been put out, fire officials said.
The cause of the fire remains under investigation.