Excerpts from abc7chicago.com:

The Chicago Fire Department received a call just after 9:20 a.m. of smoke coming from a building near 67th Street and Cregier Avenue. While crews were looking for the fire, they pulled down on the ceiling and it fell on top of them. Three firefighters were transported to University of Chicago Medical Center in serious condition.

At around 3:30 p.m., the department said that two of the firefighters were released back to active duty. The third firefighter was put on medical leave.