Two people- including one who jumped from a window -- were transported to the hospital in critical condition. A third person is in good condition after being treated. Two firefighters who suffered minor injuries while battling the blaze and are OK.
One person- who has not been identified- was pronounced dead at the scene.
"When I heard the smoke detector and looked up and saw all the smoke above us," said Andrea Elmore, resident.
"I opened the door to see what was going on and heard people scream, oh my god, oh my god, and I didn't hear the fire alarm at first and heard screams and i heard the fire alarm from upstairs and rushed my kids out," said Alexia Hause, resident.
Officials still on the scene said it could be arson. Witnesses say the fire apparently started in a fifth floor hallway. According to unconfirmed reports, firefighters found a gas can in the hall and someone may have been seen running from the area shortly after the fire started.
"At the time we have no cause for this fire. The fire only penetrated one apartment and we did have fire on floor number four as well," said Dist. Chief Patrick Malone, Chicago Fire Department.
"Fifteen years...we have had this building and zero claims. No problems, nothing," said Sardar Shakhan, building owner
Officials said most of the fifth floor units are a complete loss. There is a lot of water damage on some of the fourth floor units as well. About a dozen residents are being displaced and the Red Cross is on the scene trying to help them find housing for tonight.