Excerpts from chicago.cbslocal.com:

An industrial fire broke out at the Nickel Composite Coatings, a nickel plate processing company at 6454 W. 74th Street in Bedford Park Sunday night (3/15/20). Due to materials on scene, crews were concerned about hazardous materials. A second alarm was struck fire for additional companies. 

The cause of the fire may have been a faulty electric heater. Officials said the fire may have caused around $50,000 in damage.