City of Batavia Fire responded to a bedroom fire at 20 North Spruce street about 7:30p.m on Monday night.
When fire crews arrived on scene they called for a second alarm after heavy flames were coming from the second floor window.
The flames then exposed the third story apartment to the fire.
As crews attacked the flames from the outside, interior firefighters made their way inside the building to attack the fire from the inside.
Fire Chief Steve Napolitano says the the fire originated in the second floor apartment and then affected the third story apartment as well. Several other apartments suffered smoke and heat damage.
All occupants of the complex made it out okay. One cat is still unaccounted for.
A firefighter suffered heat exhaustion and was taken to UMMC to be checked out.
The Red Cross was called to assist people from at least two apartments.
The cause of the fire is under investigation.