A massive explosion in a silicon plant in northern Illinois sent at least four people to the hospital late Friday night.
The 9:30 p.m. blast at AB Specialty Silicones, located at an industrial park in Waukegan, also left an unknown number of employees unaccounted for, CNN reported.
Local police said an “active search and rescue” operation was underway, according to Chicago TV station WGN. The cause of the blast was under investigation.
Loud booms were heard and the ground shook in towns in the region, about 50 miles north of Chicago along Lake Michigan.