Chicago firefighters responded to a reported fire about 1 a.m. in the 2400-block of West 34th Street in McKinley Park.
It appeared to be a difficult blaze to extinguish, as firefighters could be seen dodging flames shooting through the building's roof, and one firefighter appeared to fall while coming down a ladder. He was seen being taken to an ambulance in a neck brace, witnesses said.
He suffered an injury to his upper body, CFD said. He was transported to Stroger Hospital and has since been released.
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Everyone inside the home, including some pets, got out safely.
Fire officials said the blaze started on the ground floor, and two people were displaced.
The fire spread to the building next to the home, but nothing inside was damaged.
CFD said there were working smoke alarms, which likely alerted the residents to the fire.
The fire's cause remains under investigation.