6 injured, including firefighter, after large apartment building fire in West Chicago

CHICAGO (CBS)-- Six people, including a firefighter, are recovering, and 100 were left homeless after a fire broke out at a large apartment complex in suburban West Chicago overnight. 

Just after 1 a.m., firefighters responded to the building at 813 Burr Oak Drive and found two balconies and one apartment on fire. 

West Chicago Fire Chief Patrick Tanner said residents were on their balconies trying to escape the flames.

"The amount of fire on the second and third floor is incredible. I've been doing this for 40 years, and this is one of the fires where you walk through and expect to see somebody very seriously injured, and we are very fortunate that did not happen today," Tanner said. 

One firefighter was taken to the hospital to be treated for a twisted knee injury. Five people who live in the building also were hospitalized, including a pregnant woman who jumped out of a third-floor window. 

Most of the injuries were minor, but Tanner said one victim was later airlifted to Loyola University Medical Center to be treated for burn injuries.

Investigators have determined where the fire started, but the cause is still under investigation. 

Tanner said about 100 people have been left homeless, and they are reaching out to a nearby church to see if the church can provide them with a place to stay.

"We think one half of the building, west side, should be able to be occupied again," Tanner said. "Definitely not the other side, we've had major fire in a couple of floors and the entire roof."

While the exact cause is still under investigation, he stressed that he does not believe the fire was intentional.