Historians of science love “who knew what, and when?” question in science. We like to do so, in part, because the results are often so counterintuitive when compared with the “traditional” narratives: Mendel wasn’t really a Mendelian, Darwin’s novelty is often quite overstated, and even superficially straightforward questions like, “when was the electron discovered?” yield a considerable amount of debate about how one knows when the existence and identity of a fundamental particle is “discovered.” They rarely have answers that come in the form of names and exact dates. In fact, they usually show you something deeper about the way knowledge is produced, circulated, and agreed-upon at any given time in history.

Of all the many questions and sub-questions about the bombings of Hiroshima and Nagasaki, one of the ones that occasionally comes up is, “How much was known about the radiation effects of the first atomic bombs before the bombing of Hiroshima and Nagasaki?” Did Harry Truman know, for example, that the bombs would produce both prompt and residual radiation? Would it have changed his decision to use the bomb?

The reason it might matter is because arguably the radiation effects of the first atomic bombs are what distinguish them from “traditional” incendiary raids — i.e., the firebombing that had already been going on for quite some time before the Second World War went nuclear. (I personally don’t think they do, from an ethical standpoint, but I’ll be writing an entire post on this very soon, so let’s put that question to the side for now.)

Truman didn’t feel it was appropriate to use chemical or “poison” warfare — so perhaps, the argument goes, if he had thought about the atomic bombs not just as “big fire bombs” but instead as “big fire bombs with poison” he would have considered them an inappropriate weapon to actually use on cities inhabited primarily by non-combatants.

This is an interesting question, and one that would take a lot of careful work to answer. So I was really glad that Sean Malloy, an historian at UC Merced and the author of a great biography of Henry L. Stimson, decided to sit down and seriously hash it over. He wrote what I expect is going to be the definitive article on the subject, published this summer in Diplomatic History with the title: “‘A Very Pleasant Way to Die’: Radiation Effects and the Decision to Use the Atomic Bomb Against Japan.” For the very literal out there, Malloy isn’t himself saying that radiation sickness is a pleasant way to die; it’s from a quote by General Groves. (If you would like a copy of the article and don’t have access to the journal, I am sure that Sean would be happy to send you one if you sent him an e-mail.)

I have written a lengthy review of Sean’s article for the online-list H-Diplo. I wrote it a little while back — closer to when Sean’s article actually came out — but due to the way H-Diplo schedules things, it’s only just come out this week. You can read it online here, if you’re interested in getting my extended take on Malloy’s article.

What follows here is a summary of my main points from my review of Malloy, which summarizes his main points. So if you’re curious about anything said below, read my full review, and if you’re still curious, read Malloy’s article.

There were certainly physicists at Los Alamos who understood that the first atomic bombs would produce significant amounts of radiation, and were likely to cause both radiation sickness and nuclear fallout effects.

But J. Robert Oppenheimer never seemed to be very interested in that. Why not? It remains something of a mystery — how do you find out why someone wasn’t interested in something? Anyway, for whatever reason, he never really paid too much attention to the reports about radiation effects, and spoke almost exclusively of the bomb in terms of heat and blast effects.

Despite much lore to the contrary, the targeting height of the bomb was not chosen in order to minimize radiation effects. It was chosen to maximize blast and thermal effects. The argument that its height was chosen to minimize radiation effects is an after-the-fact argument, though it is not an entirely inaccurate side-effect.

Because Oppenheimer didn’t know/care about radiation effects, General Leslie Groves didn’t really, either. Groves actually thought he could march American troops through an area that was recently atomic bombed — had he been given the opportunity to do so, his ignorance would have actually cost American lives. Malloy thinks — and I agree — that such is a good indication that he was pretty confused on the issue.

And yet, Groves and Oppenheimer did consider radiation in other contexts — such as the health of those involved with witnessing the Trinity test. But they never seemed to have talked about it in the context of the Japanese, the intended victims of the bomb. Why not? Malloy suggests that Groves was subjected to a “self-compartmentalization” — that a side-effect of his compartmentalized project was a compartmentalized self. Health safety and weapons effects were totally different departments as far as he was concerned; he never made the linkage. This is, of course, speculative, but I like it as an explanation, because it jibes with other commonly-observed side-effects of working in highly-compartmentalized environments.

If Groves didn’t know/care, then the Targeting Committee and Interim Committee, Secretary of War Henry Stimson’s turf, didn’t know at all. If Stimson didn’t know, Truman didn’t know. Question answered, in a sense: some people knew, but they were very low on the hierarchy, and the Manhattan Project was highly hierarchical. The reasons it didn’t percolate up the chain aren’t because anyone was deliberately holding it down — it’s because knowing something and caring about it (that is, thinking it is important) are linked. (This is my formulation of the reason, anyway, and why I like to use know/care as a linked term here.)

They didn’t really care, they didn’t really know, and it never got passed up. Oppenheimer was a scientific filter to Groves, and Groves was a filter to the politicians — and a good deal of filtering had to take place for something done at Los Alamos to ever make it to Truman’s ear. (As an aside, Groves struggled with this even in explaining the basics of the project to Truman in terms the latter could understand and care about, much less technical details.)

Would it have mattered? Malloy thinks it might very well have mattered for Truman — he was markedly averse to the idea of poison warfare. Personally I doubt it would have made a difference; you don’t call off a massacre because you think it might kill a few more people than you originally intended, and the scientists would have had no way to give a plausible number for the number affected. Later estimates put the number of acute dead from radiation exposure at about 15%-20% of the total casualties from the bombings — a not insignificant number (many thousands of people), but probably not enough to change the direction of the bomb program, and probably a number that would have been dismissed as too high if it had been presented as an estimate before actual use.

Lastly, what about the allegations of an “atomic cover up” that periodically go around, which say that Groves et al. tried to hide the fact of radiation illnesses? Malloy gets into this here fairly well, too. Not long after the bombing, reports started coming in that doctors in Japan were seeing the effects of radiation sickness amongst the (apparent) survivors of the attacks. Groves thought they were just propaganda, trying to make the American people feel sympathetic to the Japanese. He asked his medical experts about it, they told him it was unlikely, and so he enlisted Oppenheimer to help deny that this could have been the case.

A few things here warrant attention:

Oppenheimer was happy to help, even though really he was kind of out of his league. Such was the way of Oppenheimer, but I also suspect he genuinely thought the reports were propaganda, as well. Prior to this instance, there actually had been fairly uninformed stories circulating about how Hiroshima and Nagasaki would be totally uninhabited for generations and things like that which legitimately were total nonsense. So Groves was already in “defensive mode” when it came to radiation effects, and already primed to see them as nonsense. The Japanese did release significant propaganda about the bomb during this period. A lot of total nonsense, like the fact that they too had atomic bombs and were just saving them up for a rainy day and now were going to use them. (The Germans did stuff like this too, of course.) It’s easy to forget, in the absence of a sense of the day-to-day from that period, how hard it would have been to separate out fact from fiction. If you look through newspapers of the day though you will be amazed at how much weird news — stuff that was clearly propaganda and false — was coming in from abroad.

To his credit, even though he dismissed the Japanese doctors’ claims, Groves also sent his own teams to Japan as soon as he could to evaluate the results themselves. They found that indeed, radiation had been a significant factor in mortality at Hiroshima and Nagasaki.

By November 1945, Groves had stopped denying that radiation sickness had occurred, even if he did, in his awful way, suggest that they were not all so bad (the aforementioned “very pleasant way to die”). But spinning, however misleading or offensive, is not the same thing as knowingly perpetuating a cover-up.

I find Malloy’s account very convincing, not just because it is well-documented and well-argued, but because it generally agrees with my reading of the primary sources. These guys were not really in the “cover-up” business. They certainly were in the “spin” business. They were willing to give in to their internal biases and believe what they wanted to believe in the absence of indisputable information. They weren’t shining heros, and they weren’t despicable villains. They muddled it out the way most people do when it came to anything other than the business of producing atomic bombs, which they turned out to be fairly good at — though even there, their superhuman prowess is usually exaggerated.

But what I really love about Malloy’s work, here, is that instead of saying, “they did know” or “they didn’t know,” he asks about how knowledge worked in the context of the Manhattan Project, which is a question of how knowledge is created, how it circulates within institutions, and how it is or isn’t acted upon. This is a very deep endeavor and one that takes you well beyond the standard ways of thinking not only about the bomb, but in thinking about any other comparable projects and institutions. This is how these sorts of questions should be worked on.

Tags: 1940s, Hiroshima, J. Robert Oppenheimer, Leslie Groves, Manhattan Project, Nagasaki, Radiation