Harry Daghlian did not expect a simple breach of safety protocols to lead to his death. 

On the evening of August 21, 1945, Daghlian went alone to work on his project at the Los Alamos site. While adding reflective brick walls made up of tungsten carbide around a plutonium core, his equipment notified him that the plutonium was dangerously close to going supercritical. 

Harry quickly took a brick away, but immediately dropped it onto the plutonium core. This caused the core to go supercritical, generating a glow of light and heat wave. Harry described feeling a tingling sensation in his hand when he removed the dropped brick. This was the moment his body received too much radiation. He lived for a nasty 25 days with a painful blistered and burnt hand. 


A peer of Harry named Louis Slotin continued working on this core one year later. Slotin was working on adding a dome over the core. The dome was never supposed to fully close, as some neutrons were meant to escape. The small gap in the dome existed by way of placing a screwdriver in-between the dome’s sides. When the screwdriver slipped out, the dome closed and quickly caused the core to reach supercriticality yet again. Other scientists were in the room this time and one described seeing a similar blue light and heat wave as Harry. While the flash was less than half a second, it was enough to expose these scientists to doses of radiation, including a lethal dose to Louis. He only lived for 9 days after this accident. 

These accidents led to the renaming of the plutonium core from “Rufus” to “The Demon Core.” While this story is very dark and sad, the silver lining was the creation of further safety protocols, including no more “hands on” experiments. Only machinery was allowed to touch radioactive core from this time on.