80 years since Hiroshima: Forgotten victims of the atomic bomb

0:25Welcome to the world, the universe and us, the weekly news podcast from New scientist. I'm Rowan Hooper. And I'm Madeleine Cuff. Now we have a special episode this week, as it's been 80 years since the atomic bombing of Hiroshima on the August the 6th, 1945. And that was followed three days later by the bombing of Nagasaki. This was the first and thankfully so far the only use of nuclear weapons in war. But after that, the world was never quite the same again. Yeah, so on this special episode, we're going to use the anniversary to discuss some of the wider implications of the Manhattan Project.

0:59I mean, the focus is often quite rightly on the tens of thousands of people killed. In Hiroshima alone, about 75 ,000 people were killed immediately, many more after the bomb. And although we usually concentrate on that, the human and the environmental cost of the Manhattan Project stretches out beyond Hiroshima and Nagasaki. and in time too it stretches out. It had an impact before the bombings and in many ways we're still dealing with it today and that's what we're going to get into. Yeah I've been exploring how climate change is having its own influence on the nuclear legacy that governments will have to address at some point and we're also going to hear from the award-winning author Annie Jacobson on the threat of nuclear weapons and of nuclear proliferation.

1:46And I've spoken to a historian who's been interviewing survivors of the bombs and a botanist who's growing trees from seeds of trees that survived the bomb. So we've got survivor humans and survivor trees on the show. But we're going to start with how the US developed and perfected its nuclear capabilities after the war. And it did that on Pacific atolls in the Marshall Islands and using those as testing grounds for their weapons. Between 1946 and 1958, the US conducted 67 nuclear tests in the Marshall Islands. I mean, most famously, they were on Bikini Atoll, 23 there. But then there's another atoll called Eniwitak, and they did 44 tests there.

2:28And then the fallout spread across the Marshall Islands. So in the 70s, the US started trying to clear up Eniwitak to make it habitable again. But the solution was basically, well, it was very basic. And now we've got climate change, it's starting to look seriously unstable. Maddy, this is something you've been looking into. What did the US do back then to try and clean up the mess in the Marshall Islands? Yeah, so the Bikini Atoll was essentially so contaminated that it had to be completely abandoned. But as you say, at Inuitac, the plan was to make it partly habitable again. So what the US military did was effectively dump as much of the radioactive material as they could gather.

3:10And that was particularly the scattered plutonium from some of the tests into a large crater that had been made by one of the test detonations. And this was all on an island called Runet. So the crater itself was about 350 feet in diameter and about 30 feet deep. And the strategy from the US military was to fill that crater with radioactive materials and then cap it with an 18 inch thick concrete lid. And that's what we call the runet dome. I'm not very reassured by that method. No, it wasn't particularly thorough. I mean, one of the big issues is that the bottom of the dome isn't lined. So the radioactive slurry that the military kind of pumped in just sits on top of this coral rock, which is permeable.

3:55So we can't think of this as a container that's like sealed off from the outside world in the way that you would expect nuclear waste to be stored. And there are even some studies that suggest that the radioactive groundwater below rises and falls with the tide because the rock is permeable. And the dome has been left that way for almost 50 years. And I chatted to Michael Gerrard. He's a professor at Columbia University in the US. He visited the Dome a few years ago while he was working with the government of the Marshall Islands. And this is how he describes it. I visited it on my first trip to the Marshall Islands about 2012.

4:35There's no fencing, no sign, nothing that would prevent somebody from going there. I walked on top of it and looked around. But it's this depository of plutonium and other radioactive material in the middle of the Pacific with no protection at all. OK, so we've got this old structure from the 70s covering a whole load of nuclear waste in the middle of the Pacific on an atoll, which we know, as you say, they're not stable geological features, are they? And even without those problems, we've now got climate change coming along. Yeah, and we know that rising sea levels seriously threaten low-lying island states, especially if temperatures rise by more than one and a half degrees above pre-industrial levels, which, as we've discussed on the podcast before, they are well on their way to doing.

5:27so that makes the Runet Dome particularly vulnerable so although this dome it was designed to withstand the impacts of severe storms and typhoon activity that was designed to 1970s standards so not with the impacts of climate change in mind so this all means that that rising sea levels storm surges and more severe typhoons or these hallmarks of a warmer world that we're now dealing with poses a real existential threat to the dome and even in the 1970s the crater was below sea level when it was high tide and it's yeah it's if you look at pictures on on google images of the dome it it really does sit very low in the water this is not something it was never a good place to put this stuff really no i think the military um essentially concluded that trying to remove all the material would do more damage ecologically than just keeping it all as much as possible in one place.

6:25That's kind of why they decided to leave it there. But with rising sea levels, the dome is expected to become partially submerged in the future, and if not completely obliterated by a passing typhoon or a storm surge. So here's Michael Gerrard again on the state of the dome as he saw it in 2010 and the threat that it faces from climate change? There was grass growing between the cracks in the dome. The dome is so thin, just 18 inches, that a very serious typhoon could blow off the top. And the US government has recognised that that is a possibility. If that were to happen, that would release the material inside the dome and it would wash into the ocean.

7:10So in July 2024, the US government's Department of Energy published a report on this issue, which was informed by research by a team at the Pacific Northwest National Laboratory. And that report essentially concluded that there would be no increased health risk for people living on nearby islands, even if the dome was to fail completely, say be broken apart in a storm. And that's because essentially the surrounding land is already so contaminated that having the extra radioactive release might not make a huge amount of difference. You've also got the added benefit of there being lots of ocean around the dome.

7:50And so all the radioactive material would be diluted pretty quickly. Yeah. But I mean, if I was living on the Marshall Islands, I don't think I would be very happy with, I don't think I'd believe that assessment, frankly. Yeah. And it's obviously quite a contentious and controversial area and something that climate activists and nuclear waste activists really want to to see some progress on so earlier this year Greenpeace sent its campaigning ship the Rainbow Warrior back to the Marshall Islands to conduct some radioactive tests on the atolls including around the Runet Dome to try and assess the future threats climate change poses to this area and that's part of a campaign for what they call nuclear justice for the people of the Marshall Islands so not just improvements to the structure of the dome, but reparations and support for the people who are living with the fallout of these tests decades and decades on.

8:43Right. But since we've mentioned sea level rise, climate change, we've got nuclear power stations all over the world built on the coasts. So this problem is going to be, maybe we're seeing the worst of it now at the Runet Dome, but it's going to be a problem all over the world, isn't it? Yeah, the Runet Dome is a good illustration of what happens when you try and contain the fallout of nuclear activities, but you don't know what the future holds. Nuclear power plants, for example, operate for decades, which means that many that were built in the 1960s and 70s, when awareness of climate risk was pretty limited, are now coming to the end of their lives.

9:24And there's plenty of concern around rising sea levels and the threat of storm surges, threatening the integrity of facilities built on the coastlines like this. But it's not just rising sea levels and storm surges that we should be worried about when it comes to nuclear infrastructure. Only last week, there were wildfires raging through Turkey, and they came perilously close to a new$20 billion nuclear power plant that's under construction in the country. Or we could look at France, where lots of the nuclear power infrastructure is built near rivers. but during summer droughts the river levels dropped so low that the nuclear power plants are having to be shut down because there isn't enough river flow available for them for the reactors to be kept cool enough so it's not just rising sea levels we need to think about when we think about the climate risk that is posed to nuclear infrastructure yeah well i mean it was it wasn't climate change it was an earthquake and a tsunami that caused the fukushima disaster but that was still a nuclear power station on the coast and a massive storm surge that overwhelmed it.

10:29So, I mean, that was in a way a sort of indication of a worst case scenario. On the other side, people would say, yes, but fossil fuels still account for far more deaths, in fact, than do nuclear power. But as you say, it's something we're just going to have to take account of more and more in the future. Yeah, I spoke to a nuclear engineer who was pretty insistent that there are mechanisms in place to make sure that this infrastructure is built to withstand worst case scenarios and any new infrastructure that's built has taken future climate risks into account and they also make the point that as a major producer of emissions-free power some nuclear energy is going to be essential to having a zero carbon future so you know there's things to weigh up on both sides here to what extent do we need nuclear to be part of a of a low carbon transition versus the risks of escalating climate change to those facilities.

11:28Yeah, I do feel it's neglected. I'm glad we've raised this because it's certainly in my mind, this future of future proofing nuclear power is something that I think is neglected a bit. Yeah. And it's not just power, it's military facilities that have nuclear stations. Money Money is going to have to be spent upgrading some of this infrastructure to protect it from the future. And that's military and civil infrastructure. This episode is brought to you by Google Chrome. You think you know a browser, but Gemini and Chrome, that's new. It can help you with practically anything on the web, like restoring a vintage motorcycle from a 50-page restoration block, or finally break down that long article you've had open for weeks.

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12:22Okay, we want to talk a bit now about the survivors of the bomb. So atomic bomb survivors have a specific name in Japanese. It's called hibakusha, and hibaku means bomb and sha means person. And I've been looking at the work of M.G. Schefter, and he's a professor of history at Shizuoka University in Japan. For the last several years, he's been interviewing these hibakusha, and he's written up their stories in two books, Hiroshima, which was out last year, and Nagasaki, which is out this year. And I spoke to him about his interviews. I decided to focus on survivors who are old enough to have detailed narrative memories, not only about the bombings themselves, but also about what life was like in Japan in the 1940s and even 1930s.

13:09This meant that my interview subjects were already in their mid-80s or older when I first met them. The handful who are still alive in 2025, and whose precious and irreplaceable personal memories have yet to disappear into the mists of advanced age, are now in their mid-90s. They are quite literally the last witnesses of Hiroshima and Nagasaki, the last living human beings who can give firsthand testimony about those cataclysmic historical events, reminding the rest of us, with unimpeachable personal moral authority, of the need for humanity to see that nuclear weapons are never used in anger again.

13:49from 2016 until 2020. When I began writing what would become the twin volume Embers series, I had the solemn honor and privilege of being able to interview 51 Japanese and also Chinese and Korean hibakusha. I will never ever forget the stories they shared with me, and I can assure you that you will never forget them either. It's really something when you speak to or hear directly from people who have experienced something so massive, isn't it? Yeah, it's really powerful to kind of hear it directly from them. Now, we quite rightly focus on the costs of the atomic bomb in terms of the human lives and health in Hiroshima and Nagasaki.

14:32But we also wanted to take this opportunity to examine how the health costs of the Manhattan Project more generally go far beyond these cities. Reporter Jeremy Su is here with us to talk about the global health toll of the Manhattan Project. Hi, Jeremy. Hi, Maddie. And hi, Rowan. Thanks for having me. So with each anniversary, we typically see commemorations focused primarily on the tens of thousands of Japanese people who died when the bombs fell on Hiroshima and Nagasaki. But what many of us don't appreciate is that the human cost of the Manhattan Project stretches far beyond Japan and began long before August 1945, right?

15:08Right. That's right. We obviously all know the people in Hiroshima and Nagasaki experienced a full terrible force of the bombs. But those bombs were only really made possible by a supply of uranium from mines that were already operating in the US, Canada, and what was then the Belgian Congo in the 1920s and 1930s. And the workers who were digging out that uranium were often indigenous peoples whose lands had previously been taken over by the US and Canadian governments, or Congolese people who were then living under Belgian colonial rule. Wow. I had no idea about this aspect of the making of the bomb.

15:49So why was the US sourcing its uranium from the Congo? Yeah, it's curious. So the Shin Kolobwe mine in the Congo actually had the distinction of containing the purest concentrations of uranium anywhere in the world. We're talking about like basically 65 % concentration compared to less than 1 % uranium in ores that were mined from like US and Canadian mines. Wow. So yeah, a huge difference. And that meant that really spurred the US government to obtain rights from the Belgian government to get hundreds of tons of this uranium or from that mine each month. And that mine itself ended up providing about two thirds of all the uranium used in the Manhattan Project.

16:35Wow. And so of course, the Congolese workers were very carefully looked after and trained in radioactive handling and given state-of-the-art protective gear, right? Yeah, unfortunately, no, they were definitely not given any of that. They were not even really told what they were digging up. And there was a lot of secrecy overlaid on top of this because of the secrecy around the Manhattan Project. And the result is they were working with no protection in these open pits, digging out radioactive uranium ore. Wow. Yeah, it's really, unfortunately, a similar story when you look at basically any of these uranium mining operations, for example, with the indigenous Navajo people who worked in the US uranium mines that were on Navajo nation lands.

17:17And then also the indigenous Delaunay people who worked in the El Dorado mine in Canada. The mine operators and governments really just kept all these workers in the dark. What do we know about the health consequences for all those workers in their communities? Yeah, unfortunately, it doesn't seem like there's really been a comprehensive study of the health impacts on, for example, the Congolese workers and the local communities. But we are seeing clear health consequences from uranium contamination of, for example, Navajo Nation lands and water with the uranium mines that were operating there.

17:50And even when those mines were eventually closing down during the later stages of the Cold War after World War II, Navajo miners and community members were at that point dying from a whole host of ailments, including lung cancer, kidney failure. and other health conditions. Even very recent studies of people there have shown high levels of uranium in the bodies of newborn babies and their mothers. And I mean, if that's all going on in a former mining community, I wonder what sort of health toll that we see in areas where there's other aspects of nuclear weapons development. For sure. I think we definitely saw there was a much broader health impact across all the Manhattan Project's production and testing sites.

18:38For example, the uranium enrichment process and plutonium production for the first atomic bombs. Those really contaminated a lot of local waterways and the air near sites such as Hanford in Washington State, Los Alamos in New Mexico, and Oak Ridge in Tennessee. That led to health consequences such as women experiencing stillbirths, newborns with various congenital health problems, and then, as we've said before, adults developing cancer and other health conditions. And then there's the testing, right? So what about the impact of the Trinity test in July 1945? That was the test that marked the first ever atomic bomb explosion.

19:19Right. The fallout from that Trinity nuclear test in New Mexico ended up contaminating basically hundreds of miles of land downwind from the test site. So that meant a lot of farming communities and towns were basically people breathing in radioactive dust, sometimes drinking radioactive milk from local cows and maybe consuming irradiated fish and other wildlife. I mean, Jeremy, is there a case to argue that they didn't know it would do that? And it's all very unfortunate, but we didn't know there was going to be all these radiation problems. I mean, I think you could, of course, say we certainly knew a lot less then about radiation and radioactivity than we do now.

20:05But I think at the same time, it was clear that there was a lot of information was kept from all these people long after there was more awareness of the scientific and health consequences of nuclear bombs and nuclear testing. Yeah. And the point is that weeks and even years before the bombs were dropped on Hiroshima and Nagasaki, we already had these serious health impacts around the world. Right. And as you said earlier, the Japanese term for the survivors of the atomic bomb, hibakusha. And we often tend to think of those hibakusha as being primarily Japanese. But in fact, there are also others such as many Korean hibakusha.

20:51Yeah. I mean, I went to Hiroshima once and I learned there that the Koreans in Japan, I mean, they've faced a lot of discrimination and straight out racism from the Japanese for years. But what I learned that was really shocking was that the memorial to the Korean hibakusha in Hiroshima, at first it wasn't inside the official peace park. They put it outside and there was a lot of bad feeling about this. And there was a sense that the Korean hibakusha were less important than the Japanese ones. And eventually that memorial was relocated and now it's in the sort of official peace park. But I can see that there has been this discrimination for years.

21:33Yeah, no, thank you for sharing that. I mean, I think that really is a legacy of the fact that if we go back to World War II, and even before then, there were hundreds of thousands of Koreans living in Japan because Japan had seized and colonized Korea in 1910. So then basically, there were many Koreans working as forced laborers in the cities of Hiroshima and Nagasaki when the atomic bombs fell. And, you know, the very conservative estimates suggest at least 20 ,000 Koreans maybe died into bombings, if not more. But that also meant there were like tens of thousands of Korean survivors who eventually returned to their homeland after the war.

22:12So what happened to the Korean Hibakusha and their descendants? Well, it was unfortunately a really difficult time right after World War II. Not only were they grappling with all these long-term health problems of radiation exposure that we've talked about without really getting any government assistance or recognition. They were living through just really tumultuous times. Korea was divided by the Allies right after World War II into South Korea and North Korea. And that set the stage for the Korean War in 1950, which was incredibly devastating. Civil War effectively killed millions of Koreans.

22:46But there ended up eventually being basically three communities of these Korean atomic bomb survivors. So basically a smaller number that stayed in Japan. some in North Korea, and the largest concentration in South Korea. And this community in South Korea is called the Hiroshima of Korea, right? That's right. And that's because an estimated 70 % of the Korean survivors of the Hiroshima bombing originally came from this one area called Hapjong County, which is primarily a rural farming community in modern day South Korea. And so naturally, many of those people returned to Hopjong County after World War II, and the remaining living survivors and many of their descendants are still there today.

23:31It does seem like things are slowly getting better in terms of recognition because the vice governor of Hiroshima Prefecture recently visited that community in Korea. So it's maybe getting slightly better, but as you say, it's really important to recognize that there is a much wider group of people that were affected by those first two bombs. For sure. And as all these stories that we've covered, these are really just a few of the stories of the total human cost of making the first nuclear weapons. I think you obviously see a lot of these stories, unfortunately, replicated over and over again when you look at other countries' nuclear programs.

24:10Yeah, you do. We were talking about this in the office, and one of the editors, Jacqueline Kwan, she pointed out there's been four epidemiological studies looking at mortality rates among UK nuclear test veterans. And most of those were exposed to very high levels of radiation during weapons testing in the Pacific and in Australia. Right. And those UK nuclear tests also exposed a lot of indigenous peoples and local civilians to radioactive fallout, which is similar to what we've seen happen during the US nuclear tests at Bikini Atoll and other locations in the Pacific, as we've talked about. I mean, the human toll is this enduring, horrendous legacy of the development of nuclear weapons as well as the deployment of them.

24:56And we're seeing, as you're saying, we're still seeing survivors and descendants worldwide bearing the consequences decades and generations later. Yes. And I think just looking back on all that, that human cost is really worth keeping in mind, even today, as we're seeing many countries modernize or expand their nuclear weapons arsenals, essentially, or ramping up nuclear fuel production, even for, say, nuclear power plant expansions. Thanks, Jeremy. I do feel that people have forgotten or neglected this wider human cost. And on that note, on the expansion of nuclear weapons programs that we're starting to see or fear, I think people have also forgotten the real absolute knife edge of danger that we're still on.

25:47And it's called a hair trigger in the military, this hair trigger to be able to launch a full scale nuclear exchange. And I was reminded of this last year when I was reading Annie Jacobson's book, Nuclear War, which is this really reported out description scenario of what would happen if the US faced a first strike and they detected incoming nuclear weapons. Did either of you read that book? I have to say, I read our review of it and thought that sounds fascinating, but maybe too terrifying. I've got enough anxiety in my life. Exactly. I just couldn't quite face picking it up before bedtime each night.

26:25I don't blame you. It's an incredible piece of work. And I asked Annie about it on this 80th anniversary for her thoughts on nuclear weapons now. And here she is. The atomic bomb is a mass-killing machine. It's been called the most destructive, inhumane, and indiscriminate weapon ever created. And yet today we have even more monstrous nuclear weapons, ones the scientists involved called the super. The thermonuclear bomb is a two-stage mega-weapon. It's a nuclear bomb within a nuclear bomb. A thermonuclear weapon actually uses an atomic bomb inside of itself as a triggering mechanism, as an explosive internal fuse.

27:22An atomic bomb will kill tens of thousands of people, as did the ones dropped on Hiroshima and Nagasaki. A thermonuclear bomb, if detonated on a city like New York or Washington or Paris or Seoul, will kill millions of people in a superheated flash. Nuclear weapons are insane. Nuclear war is insane. Every person I interviewed for my book, Nuclear War, A Scenario, knows this to be true. The whole premise of using nuclear weapons is madness. It is irrational. And yet, here we are. On the 80th anniversary of the atomic bombings of Hiroshima and Nagasaki, I think it's a perfect time to think about how we must all pull back from the brink.

28:26That was Annie Jacobson on basically the madness as well as the horror of nuclear weapons. We're going to try and end on a note of hope though after all that. We did already mention the word in Japanese that refers to people who survived the bombs, the hibikusha. And hibiku means bombed, shy as person as I said. But there's a word I've only just learned called hibaku jumoku, which means bombed tree or survivor tree. And this refers to trees that survived the atomic bombs. How on earth can a tree survive a nuclear bomb? Yeah, I know. You can see in archive photos of Hiroshima, you can see the peace dome there.

29:04Everything else is flattened. And there are a few trees, remarkably, just right by the hypercentre that survived the bomb. But what people have done now is to gather seeds from these survivor trees and send them around the world. Such a nice idea. What do they do with the seeds once they're disseminated? So they grow them in various gardens around the world, grow these descendants of survivor trees. And the idea is build a message of peace and resilience, ecological living, and hope for a nuclear-free world. It's through a volunteer organisation called Green Legacy Hiroshima. And we have some of these survivor trees now in the UK.