He survived the nuclear explosion in Nagasaki, then spent his life treating victims

Some 190,000 survivors of the World War II nuclear attacks— the ‘hibakusha’ — still carry with them memories of death and destruction, radiation-induced diseases and social stigma. Three of them accepted to recount their story: Masao Tomonaga, Sadao Yamamoto and Yoshiro Yamawaki dig into the darkest reminiscences of their past in the hope that today’s world becomes free of the nuclear threat.

Humanitarian Law & Policy
6 min readMar 28, 2017


A man suffering serious burns is being treated in a Hiroshima hospital, in the aftermath of the nuclear explosion in August 1945. © ICRC Archives

This interview with Dr Tomonaga was conducted in February 2015 in Nagasaki by Vincent Bernard, Editor-in-Chief of the International Review of the Red Cross, and Hitomi Homma, Communication Officer, ICRC Tokyo.

Dr Masao Tomonaga survived the detonation of the second atomic bomb in Nagasaki on 9 August 1945. He graduated from Nagasaki University Medical School, specializing in internal medicine and haematology. He was previously the Director of the Japanese Red Cross Nagasaki Atomic Bomb Hospital, and researched the after-effects of atomic bomb radiation on human health. He is now Chairman of the Nagasaki Global Citizen’s Assembly for the Elimination of Nuclear Weapons and directs a clinic attached to the Atomic Bomb Survivors Nursing Home.

What was your personal experience of the atomic bombing and its immediate aftermath?

At the time of the bombing, I was two years and two months old. That morning, I was sleeping on the second floor of our Japanese-style wooden house in a Japanese-style bed, when suddenly the blast from the atomic bomb crushed our house. Fortunately I was not harmed, maybe because I was protected by the bed itself and the ceiling of the house did not hit me directly.

After the blast, my mother, who had been preparing food, searched for me in the rubble of what had been my bedroom, and found I was still sleeping in the bed. She got me out of the ruins of our house, which burned to the ground ten to fifteen minutes after the initial blast. These are the dual physical effects of an atomic bomb: first the blast and then the fire.

Harsh medical consequences such as severe burns and fractures and other bodily injuries, for example due to broken glass, were typical effects of the atomic bomb blast. Some people were struck by so many shards of broken glass that some of the glass had to be left inside their bodies.

Burn victims from the nuclear explosion are being treated in a Hiroshima hospital, August 1945. © ICRC Archives

People near the blast itself suffered burns. People who were much further away from the hypocentre at the time of the blast suffered other injuries. A British Navy research team came to Nagasaki and observed the hibakusha. One officer wrote that each victim was killed three times: once by the blast, once by the heat, and once by the radiation. If an individual was closer to ground zero, her whole body became charcoal. Those terribly burned victims received a lethal dose of radioactivity as well as heat radiation, and also fractures.

As a doctor and a scientist, you specialized in the effects of radiation. What are some important findings on the health consequences of the atomic bomb?

Research shows that “short-distance survivors” — those who were located within 1.5 km of the hypocentre of the blast — have an average rate of leukaemia about fifty times higher than the average rate of leukaemia occurrences among distant survivors. This was the first finding of an atomic bomb radiation-induced disease, leukaemia.

The initial leukaemia peak disappeared after about fifteen years, but to my surprise a second leukaemia peak is now appearing, this time among the survivors who were children younger than ten years old at the time of the bombing. They are now approximately 85 years old. These survivors develop a special type of leukaemia, called myelodysplastic syndrome (MDS), which occurs in the elderly.

Seventy years after the atomic bombings of Hiroshima and Nagasaki, Red Cross hospitals are still treating thousands of survivors and identifying new links between radiation exposure and fatal illnesses. Warning: some of these images could be distressing.

It is very clear that the atomic bomb affects the human body for a lifetime, which means that the atomic bomb radiation affected survivors’ DNA. Double-strand DNA is the driver of the cells that make up the human body. Radiation from the atomic bomb injured these double-strand DNA and, while still hot from the radiation, the damaged DNA erroneously re-coupled, developing malignant genes, or abnormal gene fusions that cause various cancers, including this second type of leukaemia, MDS.

What other non-medical consequences were caused by the atomic bombing?

Nagasaki University doctors performed extensive psychological research in 1995, on the occasion of 50th anniversary of the atomic bombing. We found that about 7,000 survivors showed a very high incidence of depression and post-traumatic stress disorder after fifty years, a very large-scale psychological consequence. They suffer from flashbacks to the memory of the bombing, causing their mental health to deteriorate. This was the first data about psychological research. I showed this data (.pdf) at the first Conference on the Humanitarian Impact of Nuclear Weapons, held in Oslo in 2013.

There are also other non-medical effects. First of all, there were financial or economic problems. Most of the survivors lost their houses and belongings and became destitute. In the first five to almost ten years, no economic help was provided by the Japanese government. Because of this, survivors united to protest to the government, asking for hospital and medical care as well as economic support.

That was the beginning of the survivors’ movement, whose long history of protest still continues today. Survivors want the government to admit that their present condition, physically, mentally and socially, is due to the atomic bombing.

How were the survivors regarded by the rest of the Japanese people?

There was some social stigma. Some people could not get married in the very early recovery phase, in the 1950s and early 1960s. Many people who were not exposed to the atomic bomb were hesitant to allow their sons or daughters to get married to atomic bomb survivors. That was a kind of social discrimination.

But gradually this segregation disappeared and many survivors could have a normal family life. It took almost ten years to reach an understanding of the effects of the atomic bomb. Some people were heavily affected — those who were located a short distance from the centre of the blast — but those who were some distance away seemed fine. Once this was widely recognized, there was no more of such discrimination in allowing marriage with survivors.

With more than seventy years of life experience in and around Nagasaki, what are the main lessons you draw from your experience treating and interacting with survivors?

I have unique viewpoint in two ways: as a survivor myself, and as a scientist, a medical doctor who can see the effects at the DNA level. By combining these two points of view, I see that we as human beings are facing very serious questions about nuclear technology.

Human civilization developed nuclear fission technology, which became, on the one hand, nuclear weapons, and on the other hand, nuclear power stations. This innovation brought a very meaningful energy source as well as a very destructive and inhumane weapon that has horrific effects on the human body. These are the two faces of nuclear technology.

The outcome of my seventy years of observation is that the Japanese population, as well as the rest of the world’s citizens, need to seek a way towards world peace, without nuclear weapons.

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