Excerpts from nbcchicago.com:

More than 100 people were displaced and six people including a firefighter were hospitalized after a massive fire engulfed an apartment complex overnight in West Chicago.

Firefighters responded to the 28-unit apartment complex, located on Burr Oaks Drive, at approximately 1 a.m. When crews arrived, they saw two balconies on fire and one unit overtaken by flames. Crews immediately went into rescue mode as some residents, including a pregnant woman, were trapped and forced to jump.

One firefighter was transported to the hospital with smoke exhaustion.

The fire originated in an apartment unit, although the fire is believed to be accidental, the cause remains unknown.