The Cecil Kelley criticality accident involved an inexperienced 28-year-old Kelley who was permitted to operate a large capacity mixing tank of potentially dangerous chemicals.
Cecil Kelley was a 38-year-old chemical operator with 11 years of experience, with more than half of that time spent at the Los Alamos lab, where one of his duties was to operate a large (1000-liter capacity) stainless-steel mixing tank. 
