The “catastrophic explosion” hit around 9:30 p.m. local time, said Cmdr. Joe Florip, a Waukegan police spokesman. Three employees are unaccounted for, Waukegan Fire Marshal Steven Lenzi said. Florip said he would “categorize this as a massive explosion.”
“Many neighboring properties are going to have damage,” he said.
The fire has been extinguished, and hazardous materials technicians and other teams are on the scene and searching, Lenzi said. No cause has been determined, and the state fire marshal will assist with an investigation, he said. Florip said the plant was open at the time of the explosion.
Lenzi said everyone affected was an employee working at the time. Four were taken to area hospitals with moderate to serious injuries, officials said. Two others were seen but requested no treatment.