The entry gives the night of 3 January in outline. This piece follows the Commission’s own “Sequence of Events,” which Combustion Engineering printed in full in its interim report, through the six days it took to bring the three men out and the three weeks to bury them, with what the Commission’s medical director and its health and safety division wrote afterwards about what they had learned. The site had an emergency plan, and it worked as far as it went. Nobody had planned for this.

The alarm

“First indication of trouble at the SL-1 (Stationary Low Power No. 1) reactor was an automatic alarm received at Atomic Energy Commission Fire Stations and Security Headquarters at 9:01 p.m. (MST) January 3, 1961. The alarm was immediately broadcast over all NRTS radio networks. At the same time, the personnel radiation monitor at the Gas Cooled Reactor Experiment gate house, about one mile distant, alarmed and remained erratic for several minutes.” The alarm was the kind that could be set off by heat or by a pressure surge in the space above the reactor floor. The fire department at the central facilities, eight miles away, and the security force answered it, and a health physicist from the Materials Testing Reactor, run for the Commission by Phillips Petroleum Company, was called.

The fire engines were at the SL-1 fence at about 9:10. Security patrolmen opened the gate and the south door of the administration building, and firemen with breathing sets and survey meters went through the administration and support buildings looking for the operators and for fire. They found neither. At the entrance to the reactor building the radiation was high enough that they withdrew to wait for health physics. At 9:17 the Phillips health physicist arrived and went with a fireman as far as the foot of the stairs to the operating floor, “where they encountered a radiation level of 25 roentgens per hour, the limit of the survey meter they were using.” They came out and searched the other buildings again, meeting fields of half a roentgen to ten roentgens an hour, and saw no one. A radio check to the station’s other installations confirmed that the three men had gone to none of them.

At 9:35 two more Phillips health physicists arrived already in protective clothing, with a meter that read to 500 roentgens an hour. One went up the stairs with two firemen until the meter read 200, and the party withdrew to plan. Then, with the Commission’s approval, the other went to the top of the stairs with a fireman and looked at the reactor floor. “Observed radiation levels of the order of 500 R per hour forced their quick withdrawal. They saw some evidence of damage but no bodies.” By 9:36 the Idaho Operations Office, Combustion Engineering and Phillips had been told, and the people who would run the night were on the road from Idaho Falls, forty-one miles away. At 10:25 the Idaho office declared a Class I disaster over the station’s radio.

The first entry

Four Combustion Engineering men arrived, among them the plant’s own health physicist, confirmed that the three military men on duty had not left the site, and decided to go into the 500-roentgen field. “At approximately 10:35 p.m. the Combustion Engineering supervisors for plant operations and health physics, wearing Scott Air Paks and carrying two 500 roentgen scale Jordan Radectors, entered the reactor operating floor for less than two minutes. They saw two men; one moving. They withdrew and returned with two more Combustion Engineering men and an AEC health physicist.” Two of the five picked up the man who was alive and put him on a stretcher at the head of the stairs while the other three saw that the second man was dead. “The group got the stretcher down the stairs and out the west door within three minutes of entry, and put the stretcher in a panel truck.” The truck met an ambulance; the ambulance met the Commission’s doctor at the junction of Highway 20 and the site road, Fillmore Boulevard. “When the doctor examined the casualty at 11:14 p.m. he pronounced him dead and the ambulance returned with the body to the SL-1 site pending a decision on the temporary disposition of the body.” The night nurse, Hazel Leisen, had reached the ambulance before the doctor did and heard, by the site historian’s account, the man’s last breath.

At about 10:38 another party, two soldiers and two Phillips men, had gone on to the floor to find the third man. “They located him and determined that he was dead and did not attempt to remove him.” The five men of the first party had taken 23 to 27 roentgens of gamma radiation each. They went to the gas-cooled reactor building up the road for a first wash, stopping on the way to let one soldier and one health physicist close the doors of the support building against the spread of a fire, and on to the decontamination trailer at the highway junction, and from there some to the dispensary at the central facilities and some to the Chemical Processing Plant. The Commission’s health physicist in charge, “having concluded that the remaining two operators were dead,” suspended the rescue and ordered everyone back to the roadblock. Between midnight and 3 a.m. about thirty people who had been at SL-1, firemen, patrolmen and soldiers, went through the dispensary for a second decontamination, in a basement room nine feet by thirteen with one shower, an outside door and containers for their clothes. Their badge readings and urine samples came back at about 3:30 and all were released.

The body in the ambulance

The dead man was reading about 400 roentgens an hour at the head, 100 at the feet and 200 to 300 over the rest of him. The dispensary was built for the living. “Because his level of radiation was so high, we had no place to put him,” the medical director, George Voelz, said long afterwards. “We left him in the ambulance until we could figure out what we were going to do next. The ambulance was sitting out in the desert, amongst the sagebrush.” The decision was to get his clothes off before the morning traffic came on to the station, and to do it outside, at twenty below, in anti-contamination suits, by the headlights of two cars, with the health physicists allowing a minute. “They had a stopwatch on us, and we got the job done. I remember we went a few seconds over. I think it was a minute and seventeen seconds.” The Commission’s sequence records the attempt at about 6 a.m. by a team of five and a maximum exposure of 770 millirems; it also records that “first efforts to decontaminate the body resulted in no significant decrease in the readings.” The clothes, soaked in the explosion and frozen through the night, had been one block of ice. The body was wrapped in blankets, lead aprons were draped over the driver’s seat, and at about 6:30 the ambulance went to the Chemical Processing Plant, where an equipment decontamination room lined with stainless steel became a mortuary and the body went under ice in a sink.

The second man

On 4 January the recovery was deliberately slowed. The men were past saving, and the Idaho office’s director of health and safety, John Horan, meant to lose no one else. Six soldiers volunteered and spent the day rehearsing. The body lay in a field estimated at 750 roentgens an hour. “A recovery team consisting of six military personnel and two AEC health physicists proceeded from the decontamination check point on Fillmore Blvd. near U.S. Highway 20, after having been extensively briefed, rehearsed, and attired in protective clothing, to the entrance of the SL-1 compound at about 7:30 p.m.” A blanket was laid on the control-room floor. The time on the reactor floor was limited to one minute, and one health physicist held a stopwatch at the door. “Having been briefed as to the location of the body to be recovered, the two-man team entered the reactor operating floor and proceeded directly to the body. One man picked up the victim’s legs while the other grasped the body around the shoulders and they moved rapidly out of the high radiation area and down the stairway. Their one minute limit in the reactor area did not expire until they were part way down the stairway.” A second pair carried the body out of the compound on the blanket; its coveralls were cut off; it was in an ambulance at 8:08 p.m. A third pair went up to look at the floor and the third man. The doses for these entries ran from one to about thirteen rems.

That night the physicists at the station had their first hard evidence of what had happened. The men’s film badges had been blown away. But the gold buckle of a watchband, the brass screw of a cigarette lighter and a gold ring had become radioactive, and the isotopes, copper-64 and gold-198, are made only by neutron capture. A metal fragment shaken out of one man’s clothing carried the fission product yttrium-91. Someone also ran in and brought out the logbook, a neutron detector and the plant’s instrument charts, all but one. The reactor had gone critical.

The man on the ceiling

The third man was pinned to the underside of the fan floor, thirteen feet above the reactor head, by the shield plug of rod 7, which had carried him up and stuck between two beams. The field there was above 500 roentgens an hour. Nobody could climb a beam to free him, and the physicists were afraid that anything knocked loose, the body or the plug or debris, would fall through the open nozzles into a core whose state they did not know. On the evening of 5 January an official photographer in protective clothing and breathing apparatus was given thirty seconds on the floor; he went in only long enough to trigger his camera, came out to a less radioactive place to change film, and went back, and got the interior photograph the planners needed for less than two roentgens. Aerial photographs on 6 January showed the roof undamaged. At 1:45 on the morning of 8 January a photographer went in again for the technical advisory committee, and photographed the control room too.

Twenty-four enlisted men and five officers of an Army chemical and radiological unit at Dugway Proving Ground in Utah asked for the job, for the experience. A full-scale mock-up of the reactor top was built at the central facilities and they rehearsed on it. “The plan for removal of this third body was to position a large net (5 x 20 feet) under it and attempt to lower the body onto the net. The net itself was fastened to the end of a crane boom. The large doors on the reactor building that are used for moving equipment in and out of the building were opened to permit the crane to position the net just below the body. A closed circuit TV camera had been placed in the reactor building to help position the net.” The crane operator’s cab was shielded with sheet metal. The television failed, and the first two-man team was used to check the net’s position by eye; they did it inside their time. “Four additional teams were used to accomplish the mission of freeing the body and lowering it onto the net. A sixth crew, outside the building was used to move the crane which held the net. The third body was removed from the building at 2:37 a.m. on January 9, 1961. The estimated doses received by the men entering the reactor building to free the body ranged from 2.5 to 7.5 rem. Recovery operations were completed at 4:42 a.m. January 9, 1961.” The Commission’s statement that day, as the Associated Press carried it, said the recovery had been “accomplished by eight men, paired in quick-moving relays to avoid excessive radiation exposure,” and that “No two-man team was in the building more than 65 seconds.”

The autopsies and the caskets

“The three victims killed by blast effects of the explosion had generalized radioactive contamination with gamma radiation levels ranging from 100 r/hr at the surface to over 500 r/hr at one foot,” the health and safety division’s annual report for 1961 records. Days under melting ice in a sink brought the surface levels down more than any later scrubbing with detergent, EDTA and citric acid did. What remained was in the wounds: fragments of the core, driven into the bodies by the blast, which no washing would remove. An eight-man team of physicians and health physicists from the Los Alamos Scientific Laboratory, in anti-contamination clothing and full-face respirators, did the autopsies with long-handled instruments made up by the station’s machine shop and cut away the tissue in which the fragments lay. The highest dose to any of them was 3.7 roentgens. The report notes that the autopsies “proved to be extremely valuable in providing positive identification of the victims and documentation of the blast effects on the bodies, which subsequently were used to establish the relative positions of the men on the reactor top at the time of the accident.” Liver tissue from two of the men was counted for sodium-24, the isotope that neutrons make in the body, as had been done at Los Alamos in 1946.

Three standard metal caskets were bought in Idaho Falls and lined by the station’s craftsmen with lead from an eighth of an inch to three-quarters thick, with extra lead around the parts still most active, until the outside read below 450 milliroentgens an hour everywhere but the bottom, which met the shipping rules of the Interstate Commerce Commission. The Commission’s general manager had proposed that the three be buried together on the station under a monument; the Idaho office argued that the families had the right to their own funerals, and won. “They were shipped to the cemeteries of the family’s choice by military aircraft under escort,” each with a health physicist to advise the undertaker. Richard McKinley was buried at Arlington National Cemetery on the afternoon of 25 January 1961, and the Washington Evening Star carried a notice that day with the three men’s names, ages and home towns.

What the medical branch wrote down

The Commission’s sequence ends with the count. “There have been 23 persons who have received radiation exposures during activities at the SL-1 site varying from three roentgens to 27 roentgens total body exposure. Of the total, 14 received exposures of three to twelve roentgens, six were in the 12 to 25 R range, and three above 25 R. Precautionary medical checkups did not disclose any clinical symptoms.” The board’s count was twenty-two. Blood counts were taken weekly for six weeks from everyone over five roentgens and showed nothing. The emergency plan had allowed a hundred roentgens to save a life and twenty-five to save property. The year’s exposure record for the station was the highest in its history, with 1,200 people used in the recovery over the year and thirty-five over the quarterly guide.

The medical services branch wrote its lessons as a list. A contaminated body at 500 roentgens an hour could be moved in an ordinary ambulance if the driver had a lead apron, and new ambulances should be specified with backs that could be washed down. Every reactor site needed a plan to decontaminate “the massively contaminated patient” in a separate building nearby, with showers, hoses, storage for clothes and a controlled traffic pattern; the equipment should include “scissors or knifes for clothing removal, hoses, nozzles, long handled brushes similar to a car-wash brush, detergent solutions and hair clippers,” and “a belt or sling to hold an injured patient in a vertical position.” Larger plants should have a room a vehicle could drive into, with an emergency surgery beside it. And the firemen, guards, nurses and health physicists should practise all of it beforehand, because “management of a living patient with similarly contaminated physical injuries would provide much more difficult problems.” The three men had died of blast. Had one of them lived, the station had no way to treat him.

In March 1962 the Commission gave certificates for heroism to thirty-two people at a ceremony in the little theatre of Idaho Falls High School: the soldiers who went in, the nurse, the two doctors, and the firemen, health physicists and contractors’ men who had gone up the stairs that night.

Sources

• Combustion Engineering, Inc., SL-1 Reactor Accident on January 3, 1961: Interim Report, IDO-19300, 15 May 1961, section III E, which prints the Commission’s “Sequence of Events Related to the SL-1 Accident” in full: every time, dose and quotation above not otherwise attributed. inldigitallibrary.inl.gov
• US Atomic Energy Commission, Idaho Operations Office, Health and Safety Division Annual Report, 1961, IDO-12021, section II 2.1, “Medical Aspects of SL-1”: the radiation levels of the bodies, the ice, the autopsies, the 3.7 roentgens, the caskets, the escorts, the exposure record and the list of lessons. inldigitallibrary.inl.gov
• US Atomic Energy Commission, SL-1 Accident: Atomic Energy Commission Investigation Board Report, June 1961, section 5, for the board’s count of twenty-two and the activation evidence. inldigitallibrary.inl.gov
• Susan M. Stacy, Proving the Principle, US Department of Energy, 2000, chapter 15, for George Voelz’s recollection, the nurse, the Dugway unit, the mock-up, the burial argument and the certificates. inl.gov
• Associated Press, “Crews Bring Last Body Off A-Reactor,” Evening Star, 9 January 1961, page 14, and “Richard L. McKinley, 27, Victim of Atomic Radiation,” Evening Star, 25 January 1961, page 24. 9 January, 25 January