When a rusting mortar round turned up on the tool bench of a public works building in Missouri, employee Derek McCubbin didn’t take any chances. “I wasn't aware if it was a training round or live, but I knew it was concerning and shouldn't be there, " he told KCTV. He called the police, who brought in military specialists. They determined the munition was live, and detonated it, leaving a sizable hole in the ground. "You never know what you're going to come across,” McCubbin said.