In Washington County four people were injured in an explosion at the Langeloth Metallurgical Plant in Smith Township.
Fire Chief Brandon Kriznik says it happened during a chemical transfer process.
"Apparently they were transferring some kind of chemical from a tanker to a stationary tank, and something went wrong and something exploded," he said.
He says there were no hazardous emissions.
No word on how seriously those four people were injured.
The explosion shook multiple homes in nearby neighborhoods.