SANTA FE, N.M. — There’s been a lot of news coverage of the 70th anniversary of the first test atomic bomb blast in New Mexico, and of the subsequent bombings of Hiroshima and Nagasaki in Japan.
Time magazine noted another related anniversary that took place last week in a piece headlined “The Strange Story of the First People to Die From Nuclear Weapons During Peacetime.”
“The first wartime deaths from nuclear weaponry were vast in number and world-changing in scope. The first peacetime deaths from that same technology were far quieter incidents, free of violence, but still illustrative of the awful power of the bomb,” begins the short article by Lily Rothman.
Manhattan Project physicist Louis Slotin wanted to go with the bombers to Japan in early August 1945. When that wasn’t permitted, he went on vacation and left a young assistant, Harry Daghlian, to continue his experiments at Los Alamos, Rothman recounts.
On Aug. 21, 1945, the article continues, “Daghlian was stacking tungsten carbide bricks as a reflector around a plutonium core, according to a Los Alamos report on nuclear accidents. The idea was that the tungsten would reflect neutrons, meaning that you’d need less plutonium to get a nuclear reaction going. Daghlian’s lab instruments showed him that the next tungsten brick he added to the stack would bring the experiment to a critical point (i.e. the reaction would begin). He moved to take the brick away, but his hand slipped and it fell into the middle of the stack. Though he quickly took the assembly apart, it was too late.”
Daghlian died from the radiation exposure that September. “In a cruel twist, the next person to be killed by peacetime atomic science, in a similar mishap the next year, was Louis Slotin,” the article says.
In 1946, Time reported on Slotin’s demise:
“Apparently Dr. Slotin and seven or more other scientists were working with ‘subcritical masses’ of uranium or plutonium. Kept apart, these masses were lifeless as lead, but if brought together to form a mass above ‘critical’ size, a chain reaction would start. Its violence would depend on the character of the materials. Probably they were midway in activity between mild-mannered natural uranium and furious plutonium 239.
“Bringing such ‘reactors’ together is touchy business. The scientists work with infinite caution, watching instruments which measure the number of free neutrons within the experimental mass. Under some conditions, the chain reaction starts slowly. But sometimes it leaps into violence in a millionth of a second. There is no explosion, no vibration, no sound. No human sense can detect the outburst of deadly radiation. The only warning, which comes too late, is a faint bluish glow. Some experts think it is caused by ionization of the air; others believe it to be an optical illusion telegraphed to the brain by stimulated nerves behind the eyes.”
Slotin suffered radiation burns and knew he was likely to die soon, but reportedly went back to work to explain his work to his staff so it wouldn’t pass away with him.
What’s now known as the Slotin Building, where the criticality accident that killed the physicist took place, remains standing as one of several historic Manhattan Project sites. The Time article doesn’t mention it, but the experiment Slotin was working on was infamously known as “tickling the dragon’s tail.”