One firefighter was slightly hurt while battling the blaze.
An investigation is now underway into what started it.
Because of the thick smoke, the nearby CTA Red Line was briefly shut down. But trains are moving again for the morning rush.
Fire rips through Uptown businesses
CHICAGO
Flames broke out around 1 a.m. in a building in the 1100-block of West Argyle. It spread to some neighboring businesses before crews finally gained control of the fire.
