A mortar round explosion at an Illinois recycling plant killed two people Monday morning and injured a third, according to media reports.

Granite City Police Chief Rich Miller told KSDK.com that it is not unusual for a mortar round to be at the Totall Metal Recycling facility because it recycles military items.

The news agency quotes a company spokesperson, who called it a tragedy and said the company’s thoughts and prayers are with the families. Totall Metal Recycling said it was cooperating with authorities during their investigation.