The Manhattan Project Heritage Preservation Association, Inc.

"Preserving, Exhibiting, Interpreting and Teaching the History of the Manhattan Project"

Home Site Map Contact Us Feedback Mission

In Memory of...

Louis P. Slotin

The Dragon Bites...Again

1910 - 1946

Web Master's Note:  This article on the life and death of Louis P. Slotin is reprinted here with permission of the author, Martin Zeilig.


This article was originally published in The Beaver in their August/September 1995 issue.
Reproduced with permission.

Louis Slotin And
'The Invisible Killer'

Page 1 of 3

A young Canadian scientist gave his life
to save his friends when an experiment went wrong

By Martin Zeilig

It happened in an instant. A sudden blue glow momentarily enveloped the room before evaporating. In that moment, as the Geiger counter clicked wildly, scientist Louis Slotin knew that he had received a lethal dose of gama and neutron radiation from the core of the plutonium bomb he was testing. It was 3:20 P.M. on Tuesday, 21 May 1946, at the secret Omega Site Laboratory in Pajarito Canyon, Los Alamos, New Mexico.

Slotin had been instructing a colleague, Alvin C. Graves, who was to replace him at the Omega Site. Also present was S. Allan Kline, a 26-year-old graduate of the University of Chicago, who had been called over to observe the procedure. Five other colleagues were close by as Slotin, a Canadian physicist from Winnipeg who had been part of the team that created the atomic bomb, performed the action that would bring into close proximity the two halves of a beryllium-coated sphere and convert the plutonium to a critical state.

With his left thumb wedged into a cavity in the top element, Slotin had moved the top half of the sphere closer to the stationary lower portion, a micro-inch at a time. In his right hand was a screwdriver, which was being used to keep the two spheres from touching. Then, in that fatal moment, the screwdriver slipped. The halves of the sphere touched and the plutonium went supercritical.

The chain reaction was stopped when Slotin knocked the spheres apart, but deadly gamma and neutron radiation had flashed into the room in a blue blaze caused by the instantaneous ionization of the lab's air particles. Louis Slotin had been exposed to almost 1,000 rads of radiation, far more than a lethal dose. Kline, who had been three or four feet away from Slotin, received between 90 and 100 rads, while Graves, standing a bit closer, received an estimated 166 rads.

A surge of heat "swept over the observers, felt even by those some distance from the source," writes Thomas D. Brock, a retired University of Wisconsin biologist who has done extensive research on early atomic-era accidents at Los Alamos. "In addition to the blue glow and heat, Louis Slotin experienced a sour taste in his mouth [and] an intense burning sensation in his left hand. As soon as Slotin left the building, he vomited, a common reaction from intense radiation." Another commentator suggests that it was as though Slotin had been fully exposed to an exploding atomic bomb at a distance of 4,800 feet.

There is some small variation in detail about what happened after Slotin knocked apart the two beryllium spheres, while using his body as a shield to protect the other men, but the official reports of the seven survivors, all of which the U.S. government "declassified" in 1985, paint a stark picture of immediate post mishap events.


According to security guard Patrick Cleary:

    "After the accident I ran out the East door and down the ramp. Probably took me about five seconds or so. When I got to the gate, it was still locked and Mr. Kline, Cieslicki and myself were the only ones there. Mr. Kline told the M.P. to open the gate. He had some trouble getting his whistle out of his pocket, but, when he did, he opened the gates and then blew the whistle. I ran up the hill approximately 1,000 feet with the others."

    Dr. Louis Slotin at work, date and location unknown.

    "Pretty soon Dr Slotin and Mr. Young came out. Mr. Young called and told us to come down to the laboratory again. As soon as we got there we drew a diagram to figure out approximately where everyone was when it happened. The only other conversation was that everyone was wondering who had gotten most of the radiation."

The sketch was used by doctors to determine the amount of radiation to which each person had been exposed.

After arriving at the Los Alamos hospital Slotin told Alvin Graves:

 "I'm sorry I got you into this. I'm afraid I have less than a 50 per cent chance of living. I hope you have better than that."

One of Slotin's close friends at Los Alamos, physicist Philip Morrison, who "watched him die" and did much of the post-accident radiation calculations, wrote that "medical and nursing care were good in fact a bit overwhelming". Nurse Annamae Dickey came every day, or sometimes twice a day, to take blood samples. Morrison reported that she "had a hard time concealing her distress when Louis pressed her for the results of her count."

Many volunteers were ready to donate blood for the transfusions doctors deemed necessary. Sadly, all efforts to save Slotin were futile. He died on 30 May after an agonizing sequence of radiation-induced traumas including severe diarrhea and diminished output of urine, swollen hands, erythema (redness) on his body, massive blisters on hands and forearms, paralysis of intestinal activity, gangrene and a total disintegration of bodily functions. It was a simple case of death from radiation, similar to what American scientists and medical personnel saw in Japan among A-bomb victims.

A few days before Slotin's death, Major-General Leslie R. Groves, the military and administrative head of the Manhattan Project, sent a U.S. Army DC-3 to Winnipeg to bring Slotin's parents to his bedside. Slotin had initially sent them a telegram and then, Morrison recalled, "with a nurse holding the receiver, he telephoned his family to tell them he had been in an accident, that he would be in hospital for a time. Since he couldn't visit them, perhaps, he suggested, his parents would come see him?"

Israel and Sonia Slotin flew home from Santa Fe, New Mexico, with the casket - which had to include a mandatory metal interline sealer - containing their son's remains.

Since the Slotins were Orthodox Jews, the U.S. Army arranged for the aircraft to arrive in Winnipeg before sundown on Friday, the beginning of the Jewish sabbath. The plane was met at the airport by Louis Slotin's brother Samuel, members of the family, friends and the undertaker who transported the body to the Chesed Shel Emes (House of Truth) Chapel on Main Street. The Winnipeg Tribune ran a photograph of Slotin's casket being transferred from the plane into a hearse with the cutline "Hero's Body Home".

Two rather moving stories about Slotin's father are recounted in a 3 June 1946 letter from Philip Morrison, who is now Professor Emeritus of physics at the Massachusetts Institute of Technology, to fellow physicist Bernard Feld:

    "When Mr. Slotin was being driven up here from Albuquerque after arriving by air, he explained why he had felt it necessary to come and why he was so much concerned. "Louis was my oldest son and every father loves his son. But there was more than that; there was respect for Louis, for a learned man".
    On the morning after Louis died, Hageman and I explained to Mr. Slotin about the need for an autopsy. He told us that it was against the traditions of the family and that he would be criticized for it when he returned to Winnipeg; but he gave permission for it now. He said that Louis had been a scientist all his life, and that when it could do him no harm, it would be wrong to prevent him adding to knowledge."