Dr. Louis Slotin and "The Invisible Killer"

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.
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 tele-phoned 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 physi-cist 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.”

The funeral took place on Sunday 2 June 1946, a warm, breezy, partially overcast afternoon. Almost 3,000 people gathered on shady Scotia Street outside the Slotin family’s home. They heard Rabbi S. Frank describe Louis as “one of the most brilliant scholars ever to come out of this city.”

Rabbi Frank also quoted from a letter, written just before Slotin’s death, by Major-General Groves which thanked the 35-year-old scientist for his “bravery and quick action which saved the lives of seven co-workers.” Louis Slotin’s story has been told before in various forms, including a 1955 novel, The Accident, by Dexter Masters. His fatal mishap was portrayed in a graphic scene in the 1989 Hollywood movie Fat Man and Little Boy, with Paul Newman somewhat miscast as the gruff, heavy-set Major-General Groves.

The oldest of three children, Slotin was born on 1 December 1910. His Yiddish-speaking parents had escaped the pogroms of Czarist Russia. Louis grew up in the energetic, East-European melange of Winnipeg’s North End.

As a boy, the bespectacled Louis Slotin demonstrated a love of knowledge. He also possessed a compelling desire to succeed. Louis was an exceptional student. He attended Machray Elementary School and St. John’s Technical High School. Slotin was a wiry, wavy haired youth of 16 when he entered the University of Manitoba.

“Louis had an extreme intensity that enabled him to study long hours,” his younger brother Sam Slotin recalled in a 1990 interview. “Louis used to make me play bridge with his friends, so that he could study instead. He liked to read inside our backyard gazebo.” Slotin won the Gold Medal in chemistry and physics. In 1933, he received his Master of Science degree from the university. One of his mentors helped him obtain a travelling fellowship. Thus, in October 1933 Slotin was able to continue with advanced scientific studies under Professor A.J. Allmand at King’s College, London, England.

Slotin was awarded a London University doctorate in bio-chemistry in July 1936. He won a prize for his thesis, which bore the title “An Investigation into the Intermediate Formation of Unstable Molecules During some Chemical Reactions”. Subsequently, Slotin spent six months as “special investigator” for the Great Southern Railway in Dublin, Ireland, testing the Drumm alkaline battery.

Much of the mystique surrounding Louis Slotin arose during his London period. In his moral and political history of the atomic scientists, Brighter Than a Thousand Suns, author Robert Jungt writes: “Ever since his earliest youth [Slotin] had gone in search of fight¬ing, excitement, and adventure. He had volunteered for service in the Spanish Civil War, more for the sake of the thrill of it than on political grounds.”

Sam Slotin later stressed during an interview with this writer that “Louis went on a walking tour in Spain. He did not take part in the war”. Barbara Moon, in a 1961 Maclean’s article, paints a picture of a young man with an impish sense of humour:
“[Slotin] regularly amused himself with the gullible by planting false clues to an imaginary and stylish past. Many of his friends came to believe, for example, that he had fought with the Loyalists in Spain and flown with the RAF and this seemed to please some strain of romance in him.”

Undeniable were Slotin’s accomplishments as an amateur fighter. He learned to box at Winnipeg’s YMCA. Those skills supposedly earned the 130- pounder the King’s College amateur bantam-weight boxing championship. Sam recalled Louis joking: “All I ever received for it was a black eye.”

In 1937, the newly-titled Dr. Slotin was unsuccessful in obtaining a job with Canada’s National Research Council. It has been suggested that bureaucratic antisemitism may have played a part in the NRC’s decision not to hire him. Like many before him, Slotin looked south.

Later in 1937 Slotin was appointed a “Research Associate,” at the University of Chicago, working on an atom-smashing cyclotron. Unfortunately, the project was poorly financed, forcing Slotin to literally work for “nothing” during a two year period. Regular contributions from his father, who was head of a Winnipeg livestock agency, helped Slotin stave off poverty.

Louis Slotin played a vital role in the construction of that first atom-smasher in the Midwest. In a letter to Slotin’s parents his former Chicago colleague Henry W. Newson wrote:
”It was hard and often disappointing work. We did the machine shop work, the wiring, the plumbing and even broke up some concrete ourselves. We finally got the thing working in the fall of ’38. During most of that year Louis worked on the oscillator circuits (a job like a big radio transmitter).
During ’39 and ’40 Louis collaborated with Prof. Evans, now head of the Bio-Chemistry department. Louis made radio-carbon on the cyclotron which was fed to pigeons. The pigeon was killed later and the liver measured. All of the pigeon but the liver was bi-product [sic] and Louis frequently offered them to us for table purposes. However, I don’t think he ever had any takers”

Slotin flourished in that hectic environment. He contributed to a number of papers in radiobiology before beginning to work in the Metallurgical Laboratory of the Manhattan District project when it was centralized in Chicago in 1942.

According to a 1962 University of Chicago document: “He was present on December 2, 1942, when the group of ‘Met Lab’ [Metallurgical Laboratory] scientists working under the late Enrico Fermi achieved man’s first self-sustaining nuclear chain reaction in a pile of graphite and uranium under the West Stands of Stagg Field.” Newson’s recollection, however, is that he and Slotin were absent when the experiment took place.

A February 1941 Winnipeg Free Press article, head-lined “New Cancer Machine is Demonstrated”, states, in part, that Slotin’s work with the 80-ton University of Chicago cyclotron was “some officials of the university declare, more valuable in some ways than radium itself in the scientific study of cancer.”

Slotin’s scientific expertise ensured eventual ensnarement by the U.S. government’s “A-Bomb Program” dragnet. In December 1944 he arrived in Los Alamos, New Mexico, headquarters of the Manhattan Project to work in the bomb physics group of R.F. Bacher. Slotin had already spent time in Oak Ridge, Tennessee, site of another part of the project, working with the Hungarian-American physicist Eugene Wigner on the problem of plutonium production.

(Wigner and fellow physicist Leo Szilard, one of the first to deduce that an uranium chain reaction could lead to an atomic bomb, met with Albert Einstein on Long Island in July 1939. They were seeking to enlist the great man’s support in alerting the U.S. Government to Hitler’s possible plans to build an atomic bomb. That informal meeting began a process which eventually led to the launching of a multi-billion dollar A bomb program code-named the Manhattan Project.)

It was while working at Oak Ridge that Slotin’s sub-stantial scientific and personal bravado were brazenly demonstrated during one bizarre incident. In July 1993 retired health physicist Dr. K.Z. Morgan, one of Slotin’s Oak Ridge colleagues, recalled the exploit during a telephone interview with this writer:
“It was Friday afternoon and Louis wanted to shut down the reactor to make adjustments to an experiment at the bottom of the tank of water which was used to absorb radiation. We said that was impossible, and we planned to shut down the reactor that weekend.
When we came back on Monday morning, I found that Louis had stripped down to his shorts, dived into the tank and made the adjustments under water. I was appalled that anyone would take such risks. It shows what kind of person he was. He was like a cowboy — but a good experimental scientist.”

Despite denouncing Los Alamos as “a disorganized mess” Slotin, notes H.W. Newson, “went to work with the same energy he always showed and was soon enjoying himself.” He quickly developed an “unrivalled reputation at assembling [the] critical firing mechanism for the atomic bomb.”

Slotin soon became a master practitioner of the dan-gerous bomb “assembling” skill. In fact, as a 1986 Toronto Star story on Slotin notes “... he had put together the core of the first atomic bomb detonated (code named ‘Trinity’) by the U.S. Army in the New Mexico desert on 16 July 1945.” One of Slotin’s most prized possessions was a scribbled receipt he received upon delivering the “Trinity” atomic bomb to army per¬sonnel. It represented the “culmination of the whole $2 billion effort” of the Manhattan Project. For his efforts, Slotin had been dubbed the “chief armourer of the United States.”

He also received two tiny, round, lead and silver commemorative pins. They are each engraved with a dominant “A” riding over the words “BOMB” and “Manhattan Project”.

Nevertheless, Slotin, to his dismay, was prevented from travelling to the Tinian Island air base in the South Pacific, the launching site of the Hiroshima and Nagasaki bombs, because “he was still a Canadian citizen several weeks short of his final American papers.” However, an officially signed 18 February 1946 Permit indicated that Slotin, now a U.S. citizen, was slated to attend the Operation Crossroads test at Bikini Atoll in the Marshall Islands.

Despite his seeming zeal, there are hints that Slotin may not have been enamoured of atom bombs, per se. In a 1982 Winnipeg Free Press story journalist Val Werier writes that Slotin’s father “was astonished to hear after Hiroshima that his son had been working on the atomic bomb.” The response was: “We had to get it before the Germans.”

Winnipeg lawyer Israel Ludwig, Slotin’s nephew, recalls his mother saying that “Uncle Lou was troubled by what he was doing” in Los Alamos, while Beth Shore, Slotin’s niece, says that during the 1960s ban the bomb movement the family “kept quiet” about her uncle’s work at Los Alamos, especially since the accident “brought such devastation” to the family. Furthermore, in November 1989, Philip Morrison, in a terse note to me scribbled at the bottom of my letter of inquiry to him, wrote that he and Slotin “talked a good deal about war and peace.” In fact, Slotin, whose talents were still required at Los Alamos after the war, was eagerly planning to resume peacetime research at the University of Chicago into both biophysics and radiobiology. He had, technically, only been on a leave-of- absence from the University of Chicago.

In a March 1946 letter to Professor Raymond E. Zirkle of the Institute of Radiobiology and Biophysics at the University of Chicago, Slotin revealed the dilemma confronting him: “I have become involved in the Navy tests, much to my disgust. The reason for this is that I am one of the few people left here who are experienced bomb putter-togetherers.”

Then the fatal accident happened. It had been ominously augured by a very similar tragedy six months earlier. Harry Daglian, Slotin’s friend and laboratory assistant, had fallen victim to “the invisible killer”. Deeply saddened by the mishap, Slotin spent many hours at his assistant’s bedside during the month it took Daglian to die.

Thomas Brock quotes from a June 1946 letter from Emily Morrison, Philip Morrison’s wife, to a friend. It reveals the “series of strange coincidences” involved in both mishaps: “Both Louis’ and Harry Daglian's accidents occurred on Tuesday the 21st; both used the same piece of material; and both died in the same room in the hospital.”

After the 24-year-old Daglian’s death, Nobel Laureate Enrico Fermi warned Slotin that he wouldn’t last a year — “if you keep doing that experiment.”

Following the Daglian accident two tiny spacers were developed to prevent the beryllium spheres from closing completely together. It was hoped that this would prevent similar incidents. But Slotin preferred a hands- on approach to experimentation.

Raemer E. Schreiber, a Slotin colleague who still lives in Los Alamos, stated in a 1993 letter to the author:
”I’m quite sure that several of us knew that he was using the Pu [plutonium] hemispheres for demonstrations of simple critical assemblies, but were not aware of his unsafe method until it was too late. After all, he was the expert in this work. But he should have never made the assembly by lowering the upper section down onto the lower one so a slip would close the gap and make the system supercritical. He should have fixed the upper assembly in position and raised the lower section gradually to increase the reactivity. Then if anything slipped, the assembly would open harmlessly. Louis knew this, of course, but apparently thought he could get by with the simpler assembly.”

Slotin’s death ended all hands-on critical assembly work at Los Alamos. We immediately started work on a remote control system with the critical assembly equipment and the operating crew separated by roughly a quarter mile. We had no more criticality deaths or injuries.

Tributes, of all sorts, came in following Slotin’s death. On 14 June 1946 the Los Alamos Times published “Slotin — A Tribute”, a poem by associate editor Thomas P. Ashlock. It began:
” May God receive you, great-souled scientist! While you were with us, even strangers knew The breadth and lofty stature of your mind ’Twas only in the crucible of death We saw at last your noble heart revealed.”

Bob Stewart, a friend and former assistant of Louis Slotin’s at Oak Ridge, expressed a sentiment shared by many: “Louis was a source of inspiration to all of us ... he would always insist upon taking the greatest risk himself. Those of us who know him know that the world has lost one of its foremost scientists.”

The Louis A. Slotin Memorial Fund was initiated in 1948 by Slotin’s colleagues at Los Alamos and the University of Chicago. A series of 15 presentations, all held at the university, were given by such distinguished men of science as J. Robert Oppenheimer, scientific head of the Manhattan Project, and Nobel Laureates Luis W. Alvarez and Hans A. Bethe. Those memorial lectures lasted until 1962 when funds ran out.

In September 1946, in response to a request for a contribution to the fund, Robert B. Brode, a professor of physics at Berkeley, wrote a revealing letter to University of Chicago colleague Professor Samuel K. Alison:
“I am enclosing a small contribution for your memorial fund for Louis Slotin. The exact details of how he was killed are not readily available to those physicists who worked on the engineering end of the job rather than pure physics. I gathered, however, from the comments [of others] who have been through here that the whole affair was a scandal.
I gather from the comments I have heard regarding the Slotin affair that he himself was guilty of negligence and that the absence of automatic safeguards was in large measure due to Slotin’s insistence that they were not necessary. I believe that more good would be done in establishing an award to be given each year to the outstanding contribution towards safety in handling hazardous radioactive materials or in recognition of successful accident-free programs. Some publicity of the outstanding ideas or of the successful research programs with hazardous materials will certainly help to reduce the type of accident in which Slotin died.”

Followup studies suggest that three of the seven survivors of the Omega Lab accident died years later from complications that might have been caused by exposure to radiation. While Clifford Honicker maintains that the U.S. “government response to that tragedy established a pattern of secrecy that still persists.”

According to my 1993 telephone interview with Roger Meade, the official archivist/historian at the Los Alamos lab: “Everything during that time period was automatically classified; but as folks ask for things we get them declassified. For many years the accident affected people’s lives, and nobody was really interested in telling the story. The physicists tried to put their lives back together. People think that it’s been swept under the rug, but it really hasn’t been.”

Today, the ultra-modern Los Alamos facility, whose researchers devote less than “50 per cent” of their time to weapons work, has some 7,800 employees and spreads out over 43 square miles. A portion of the original Pajarito Canyon lab where the accident occurred is still standing.

There is no doubt that Louis Slotin died a hero. While he was waiting for death in his hospital room at Los Alamos the authorities issued a special citation which was read to him:
“Dr. Slotin’s quick reaction at the immediate risk of his own life prevented a more serious development of the experiment which would certainly have resulted in the death of the seven men working with him, as well as serious injury to others in the general vicinity. He had that to think about as the darkness closed in.”