Two witnesses said they were driving by and saw the flames near Parkside and Diversey in the Belmont Cragin neighborhood.
2800 block north Parkside. Still and box. EMS plan 1. 5 serious to critical victims. Three females two males. pic.twitter.com/7FrqVGxjat— Chicago Fire Media (@CFDMedia) June 8, 2019
That's when they pulled over and alert everyone inside the building to get out.
"Were actually about to save people's lives. Like I can't believe no one was aware of the fire," Mia Mangual said.
All five people, two men and three women, are expected to be okay.
Officials said they believe the fire started on a back porch.
It's not clear what caused it.