Crews started battling the blaze around 3:44 a.m. at a four-story residence located at 5130 S. Kenwood Ave, according to fire officials. Chicago firefighters hosed down the apartment building from the front, the back, the alley and above.
A woman, whose age was unknown, was injured in the blaze and was transported to the University of Chicago Medical Center where she was listed in critical condition, according to police.
Eight people were displaced from the building.
CFD Fire Commissioner Annette Nance-Holt said the roof of the building collapsed.
Neighbors said the rescued resident lived in hoarding conditions, which impacted firefighting efforts.
Joan Allison evacuated her apartment in the building next door. She said she awoke to the sounds of firefighters chopping down a wooden fence to gain access to the scene.
Over 250 firefighters battled the blaze and there were 90 pieces of equipment taken to the scene.
Nance-Holt said this was a case where smoke detectors saved lives.