An explosion and fire at an industrial plant just outside Chicago injured seven people Wednesday, two of them critically, and blackened the sky with smoke.
The blaze at the Universal Form Clamp Co. plant was put out in less than two hours. The cause of the accident was under investigation.
Universal Form manufactures construction materials, including chemicals and other products used in scaffolding and concrete forming.
Authorities urged nearby businesses to close their air intake systems because of the smoke, but no evacuations were ordered. Police spokesman Rich Blass said chemicals in the plant were rendered inert by the foam used to fight the fire.
One of those critically injured was a truck driver making a delivery at the plant. He was burned over 90 percent of his body, a fire official said.