An explosion at a corn milling plant in Wisconsin left one person dead and several injured Wednesday night. The Didion Milling plant in Cambria exploded at 11 p.m. and was followed by a fire, according to Columbia County Sheriff Dennis Richards in a news briefing. Columbia County Sheriff Dennis Richards Richards confirmed that two people escaped unharmed while two people remain missing. More than four helicopters and 20 local fire departments responded to the scene. The investigation of what caused the explosion is still ongoing.