Harry Daghlian was a physicist who worked as part of the Manhattan project, the group responsible for the development of the atomic bomb. Daghlian would lose his life to his venture, after becoming fatally irradiated in an accident.
He was working with a 6.2 kg plutonium–gallium alloy bomb core that would earn the nickname the ‘demon’ core because of the small safety margin it had and two criticality incidents that occurred. One of these happened when Daghlian accidentally dropped a tungsten carbide brick on top of the core, sending it supercritical. He reacted immediately, trying to initially knock the brick off before having to disassemble the pile of bricks he had constructed to stop the reaction.
Daghlian received a lethal dose of radiation, and the radiation burn he sustained to his hand during the removal of the brick can be seen above. He received intensive medical interventions but slipped into a coma and died 25 days after the incident.