4 Marines Dead in Accident at Camp Pendleton Unexploded ordnance reportedly detonated By Newser Editors and Wire Services Posted Nov 13, 2013 5:18 PM CST 2 comments Comments Marines of 11th Marine Regiment salute at Camp Pendleton in this file photo. (AP Photo/The Orange County Register, Mark Rightmire) (Newser) – Four Marines at California's Camp Pendleton were killed today in a training accident, reports Reuters. It's not clear exactly what happened, but NBC News reports that they were killed when an unexploded ordnance blew up. The Marines, who haven't been identified, had reportedly finished their drills and were clearing the training area when the accident occurred. It follows one involving live ammunition that killed seven Marines earlier this year in Nevada.