The Los Alamos Secret

Two months before Hiroshima, John Bistline ’44 was working on the bomb that would introduce nuclear warfare to the world when things almost went terribly wrong.

(Photo by Scott Cook; Illustration by Candice Stevens) (Photo by Scott Cook; Illustration by Candice Stevens)

John Bistline ’44 knew he had to get out of the lab, and fast.


It was June 4, 1945, in Los Alamos, New Mexico. Bistline was working, as he had been for several months, on the U-235 bomb, also known as Little Boy—the bomb that would drop on Hiroshima two months later.

“We were filling this tank with water and, all of a sudden, we realized we had a real, live reactor going,” Bistline says. “And that’s when the excitement started.”

The nuclear weapon he was working on had reached criticality, meaning fission was taking place. The nuclear reactor was producing power, and much sooner than predicted, leaving Bistline unprotected.

He would be the first person exposed to an overdose of neutron radiation. He was 21.

Just a year earlier, he had graduated from Rollins with a degree
 in physics and left early, missing commencement, to work at the Metallurgical Lab at the University of Chicago. For nearly eight months, he worked on the nuclear reactor there before being reassigned to top secret Los Alamos, which at the time was referred to only as “site Y.”

There, on that June day, he was down in the canyon in a building isolated from most of the site, where he conducted experiments to determine the critical mass values for the U-235 bomb, as he had for many days before and would for several days after. That meant taking tiny half-inch metal cubes of uranium, arranging them inside a special apparatus, and slowly pumping water into the tank around them. Bistline would then measure the reactions and report his findings to the theoretical physicists.

“It turns out we were a little optimistic, and it went critical before we expected it,” he says.

When he realized what had happened, he opened the dump line to release the water, thus stopping the reactor, and ran, along with two others who were near the site at the time. Bistline remembers running to the gate, maybe the length of a football field away from the bomb, and then his memory gets a little fuzzy. He doesn’t remember exactly how he got there, but he remembers being in Robert Oppenheimer’s office with two other people—the guard and the electrician who
were on duty with him—and their bosses and bosses’ bosses, while Oppenheimer, who headed the secret site, discussed what to do. “They knew we had some exposure to radiation, but they didn’t know how much and they had no idea what the effect was going to be on us,” Bistline says.

That’s because the effects of neutron radiation were still unknown. Oppenheimer, the other theoretical physicists, and Bistline wouldn’t know that for sure until after both the uranium and plutonium bombs had been dropped on Hiroshima and Nagasaki, respectively. According to the Atomic Heritage Foundation, Oppenheimer “believed that 50 atomic bombs would be needed to defeat Japan. Scientists and military figures considered them as nothing more than large-scale conventional weapons.”

(Photo by Scott Cook) (Photo by Scott Cook)

Bistline echoed that sentiment when I talked to him on August 7, the day after the 70th anniversary of Hiroshima. He was a month shy of 92 and had gone on to get a master’s degree from Cornell University and work for many years at GE before retiring to Longwood, Florida, where he currently resides. When I asked him about the destruction those bombs caused and the lives lost, he said they thought they
were just creating bigger bombs. At the time, the U.S. was dropping bombs daily on Germany, and they thought this would cause more destruction—that was, after all, the point—but they didn’t know the impact radiation was going to have.

“We assumed we knew, but we didn’t,” he says. “And that was the big trouble.”

That Oppenheimer had Bistline in his office, essentially exposing himself and others to radiation, shows this. Even the doctors didn’t really know what to test for. Bistline recalls they were kept isolated in one wing of a hospital for two days and had their blood count taken every hour, until all seemed normal. They weren’t sick. They had healthy appetites. Their exposure was nonlethal, but there was one telltale sign.

“The only thing that I did notice, maybe a month and a half after the incident, was that I had a little fringe of new hair right around the edge,” he says, pointing to his hairline. At the time, they didn’t even know this was a result of exposure.

His exposure was minimal but because of it, he was banned from all of the major bomb experiments. While he would continue to work with uranium as before, he wasn’t allowed to go to the Trinity test site on July 16 to see what’s been described as “a flash of light brighter than a dozen suns.” Nor was he allowed to go watch the Enola Gay take off for Japan early on the morning of August 6.

He did, however, seal the bomb up in the shipping case and sign the outside, etching his name on a small relic of history that would kill at least 80,000 people but would also stop World War II, arguably saving hundreds of thousands more.