At least 20 people were displaced after their homes went up in flames late Wednesday in southwest suburban Summit.
The fire started in a multi-family home, then spread to two other buildings in the 7300 block of West 61st Street around 11:45 p.m., according to fire officials.
One firefighter was hurt when debris fell on him, but he was transported to an area hospital in good condition, officials said.
The American Red Cross of Greater Chicago is helping the four families who were displaced.
The cause of the fire is under investigation.