The Fallout Chronicles I - First Observed Effects
The Fallout Chronicles I
First Observed Effects
The next several postings will be entitled The Fallout Chronicles. Fallout is usually treated as a technical matter. The previous entry did that. The next several postings will look at it historically. The story that will emerge can be read in more than one way. But it is not a tale likely to make us proud of our Cold Warriors.
From the time of the discovery of nuclear fission at the end of 1938, the physicists knew that it might create, along with terrific heat and blast, new “radium like” elements. That was what Albert Einstein and Leo Szilard called them in the letter they wrote to President Franklin Roosevelt in 1939 to alert him to the fact that it might now be possible to build “an extremely powerful bomb of a new type.”
The physicists didn’t know much more than this. The phenomenon of radioactivity (spontaneous nuclear decay that releases ionizing radiation) had been discovered by the French scientist Henri Becquerel in 1896. (X-rays, which are ionizing, had been discovered the year before.) The radioactive element radium was discovered by Marie and Pierre Curie in 1898. Since then, physicists had learned that radioactive elements might emit different of ionizing radiation, which they had named alpha, beta, and gamma radiation. It had become become clear that in large enough doses, all these kinds of radiation could be harmful to humans.
But when it came to the “radium-like elements” that would be created in nuclear fission, the physicists knew, in 1939, very little. They didn’t know just what the new elements would be, or how strong would be the ionizing radiation they would emit, or for how long the elements would emit it. And, except for the large doses, they didn’t know what health problems might be caused for people, if any, by the lower doses of radiation.
During the Manhattan Project to build the atomic bomb, a new profession emerged—the health physicist. In the Manhattan Project, the health physicist’s job was to figure out how to protect the people working on the Project from the bad effects of ionizing radiation. First of all, instruments would need to be developed that would measure the levels of the different kinds of radiation. About the state of their knowledge at the time, one of the principal founders of the field, Karl Morgan, wrote in The Angry Genie (1999),
The extent of my ignorance of the true radiation risk… overwhelms me today…. Much of my time…involved efforts to find and develop methods to prevent radiation exposure and to determine what would be a “safe” level of exposure. Little did I suspect that there is no “safe” level of exposure to radiation…. Unfortunately, we accepted the threshold hypothesis: that so long as we avoided the skin-reddening threshold dose, all of us were safe…. Radiation-induced cancer, lens cataracts, life shortening, and genetic damage never occurred to us as a possibility except at very high doses.
As Morgan learned more about “the true radiation risk,” he found it hard sometimes to convince the authorities that the ionizing radiation was as harmful as he thought it might be. He would often get pressure to set the “safe” levels higher than he thought prudent. We were racing, after all, to beat the Germans to the bomb.
By the time of Trinity, the first atomic bomb test, on July 16, 1945, the Germans had surrendered. It was now well understood that large doses of prompt radiation striking the whole body would be lethal (In an accident, a physicist at Los Alamos had been killed by a large dose) and that there would be some danger from fission products.
Before the Trinity test, ranchers living downwind from the site were advised to evacuate for a while. Secrecy prevented them being told why. Their livestock was not evacuated. Many animals suffered burns and other injuries from, we now know, the fall-out. The ranchers seemed okay. The main thing learned at Trinity was, J. Robert Oppenheimer is reported to have said immediately after the Trinity test, that “[i]t worked.” “It” was the implosion design for an atomic bomb.
Germany had surrendered but the war with Japan was still on.
Not long after the Trinity test Stafford Warren, the chief medical officer for the Manhattan District, had reported that
the dust outfall from the various portions of the cloud was potentially a very dangerous hazard over a band almost 30 miles wide extending almost 90 miles northeast of the site.
Warren concluded that the Trinity site was "too small for a repetition of a similar test of this magnitude except under very special conditions." For any future test of a device of this size (the test yielded twenty kilotons which now is considered “low-yield”), he proposed finding a larger site, "preferably with a radius of at least 150 miles without population." Hmm. Where might we find such a site?
After Little Boy and Fat Man were dropped on Japan, more could be learned about the effects of ionizing radiation. Readings were taken in the destroyed cities and around them. The surviving inhabitants in the cities were examined. In November 1946, a little more than a year after the bombs were dropped, the U.S. set up in Japan something called the Atomic Bomb Casualty Commission. The Japanese had thought it might provide medical care. That was not its purpose. Its purpose was to study the effects of the bomb, especially of its ionizing radiation. There was still a lot to learn.
Some of the doctors assigned to the Commission offered medical help anyway.
Next: The Fallout Chronicles II: Fallout Gets a Name