Officials were working to fight the blaze and determine what caused the blast in the industrial complex outside Chicago.
ADVERTISEMENTFour people were hospitalised after a "ground-shaking" explosion and fire broke out Friday night in an industrial complex in Lake County, Illinois.
Shortly before 10 p.m. (5 a.m CEST), the Lake County Sheriff's Department said it was working to determine the cause of a blast in the Gurnee-Waukegan area."We are aware of a very loud explosion sound and ground shaking in the Gurnee area," the agency tweeted. "If you have first-hand knowledge of the incident please call your local law enforcement."
Hours after the initial blast, crews continued to fight the blaze and urged residents to stay clear of the scene. The explosion happened near the Gurnee-Waukegan border, which is about 35 miles (56 km) north of Chicago. Officials were searching for second-shift workers who may have been in the building during the blast, Waukegan police Cmdr. Joe Florip told NBC Chicago. The conditions of the those taken to the hospital had not been released, Waukegan fire Chief Steven Lenzi told the news station.
"Something exploded," resident Emily Laughlin told the station. "It looked like it was a building but they stopped everyone from getting closer." Others in the area posted photos and video of the blast online and described it as a "sonic boom." Some as far away as southern Wisconsin reported feeling the explosion, NBC Chicago reported.
Power was knocked out to nearly 1,000 residents, and windows were shattered across the area, according to the station.