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Hiroshima: The first atomic bomb


On 6 August 1945, during the final stages of the Second World War, the United States (with the consent of the United Kingdom as laid out in the Quebec Agreement) dropped the world’s first deployed atomic bomb over the Japanese city of Hiroshima, instantly killing over 80,000 people and wounding, disfiguring and poisoning tens of thousands more.

Three days later, a second atomic bomb was dropped on the city of Nagasaki, causing the deaths of approximately 40,000. In the months following the attack hundreds of thousands more would die slow, painful deaths as a result of burns and radiation poisoning, further compounded by illness and malnutrition due to survivors being left without the necessary resources for farmland and food.

Although Japan unconditionally surrendered to the Allies on August 15 1945, the bombings’ role in the surrender and their ethical justification are still debated today. They remain the only use of nuclear weapons for warfare in history. 

The Manhattan Project

When US President Franklin D. Roosevelt died on 12 April 1945 and was succeeded by Harry S. Truman, the new president knew nothing of the ‘Manhattan Project’, the hugely expensive and highly secret American-led programme to develop a nuclear bomb. The project was so top secret that Roosevelt had not informed Truman, then Vice-President, that it existed and the Secretary of War, Henry Stimson only informed Truman about the new devastating weapon being developed by physicists in New Mexico after he was sworn in. 

Whilst negotiating the post-war settlement at the Potsdam Conference in July 1945, President Truman was informed of the success of ‘Operation Trinity’, the successful detonation of the first atom bomb in the desert at Alamogordo. Although the New Mexico bomb had worked, the consequences of exploding a nuclear device were unknown and there were still scientists who believed in the possibility of an unstoppable chain reaction in the atmosphere, not to mention that the dangers of the after-effects of radiation remained a mystery.

By the time of the Trinity test, Germany had already been defeated by the allies in Europe, but Japan vowed to fight to the bitter end in the Pacific. Six months of strategic and intense fire-bombing in 37 Japanese cities had done little to break Emperor Hirohito’s regime and Japan resolutely ignored the demands for unconditional surrender. On one hand, using an atom bomb would force Japan to surrender bringing an end to the war, especially as the alternative, an Allied invasion of the Japanese mainland, risked the loss of possibly a million or more Allied servicemen. On the other, casualties among the Japanese civilian population would be huge. Truman was faced with an unenviable decision that would alter not only the future of the war, but possibly the whole future of warfare. In the hopes of bringing the war to a quick end, Truman decided the bomb was the only option.

“We knew the world would not be the same. A few people laughed, a few people cried. Most people were silent. I remembered the line from the Hindu scripture...‘Now I am become Death, the destroyer of worlds.’ I suppose we all thought that, one way or another.”
J. Robert Oppenheimer, on witnessing the Trinity bomb test

‘Little Boy’

The first bombing target was selected as Hiroshima, a port and manufacturing city of just over 350,000 people and also the site of a major military headquarters. On the afternoon of Monday 5 August 1945 a 10 ft long, 4,440 kg cylinder was loaded into the bomb bay of a modified B-29 bomber named Enola Gay (after the mother of its pilot, Colonel Paul Tibbets). That cylinder was a uranium-235 bomb code-named ‘Little Boy’. The following day at 2:45am Col Tibbets lifted Enola Gay off the runway at the US base on the Pacific Island of Tinian. The B29 was joined by two more ‘superfortresses’ carrying photographers and observers over Iwo Jima (The Great Artiste and a then-nameless aircraft later called Necessary Evil) and at 06:07 am the three aircraft set course for Hiroshima. By 8:15am they were over the city and from just over 31,000 ft ‘Little Boy’ left the bomb bay of Enola Gay. It took little more than 44 seconds for the bomb to fall, detonating around 1,900 ft above the city with a loud boom and blinding flash. At alarming speed a glowing fireball began to rise rapidly, which continued to expand into a huge mushroom cloud nearly 30,000 ft high. At the core of the fireball the temperature was around 300,000 degrees Celsius and surface temperatures reached almost 7,000 degrees Celsius. Almost five square miles of the city were destroyed; over 80,000, a quarter of Hiroshima’s population, were killed instantly and 62,000 buildings were obliterated. These deaths were caused by the sheer power of the heat and explosion from the flash and blast, but in the longer term many more would die as a result of the radiation, an unseen, indiscriminate killer. 

The aftermath

The immediate aftermath of the bombing was the incredible death toll, hundreds of thousands of Japanese effectively vapourised within a matter of seconds as the nuclear shockwave tore through the city. Later investigations concluded that anyone within approximately 3 square miles from ground zero would have been killed instantly and those within 9.5 square miles would have likely have been casualties, many of whom died later from their severe injuries. Even ten miles from the epicentre the bomb had caused fatalities. Buildings were reduced to rubble and almost half of the land considered usable before the attack reduced to ashes, rendering the city unrecognisable. 

In 1945 very few people had any real idea of the long term effects of an atomic bomb explosion. Many believed that, because the bomb exploded above the ground rather than on impact, the radiation would rise upwards with the mushroom cloud. As a result of this misconception only days after the bomb had exploded rescue workers and scientific teams were all over the city oblivious to the potential harm that might strike them later. For months after the bombings, in addition to extensive burns, many survivors began to develop puzzling symptoms: fever, chronic fatigue, vomiting, diarrhoea, blood abnormalities, hair loss. These symptoms were termed ‘radiation sickness’ and ‘Acute Radiation Syndrome’ by the doctors treating them. Over 90 per cent of the victims’ burns were ‘flash’ burns, caused by the thermal energy released by the blast, the rest were ‘flame’ burns as a result of objects igniting and engulfing individuals. The burns were often deadly as radiation impairs the immune system, leaving victims open to infection. Most of the city’s hospitals were located in the area of Hiroshima that had been destroyed and over 90% of the city’s medical personnel became victims. Although make-shift relief stations were set up, essential medical supplies, bedding and trained personnel were in short supply – by the time medical help arrived it was often too late and many were unable to be saved.

In the months and years that followed the long-term effects also began to become apparent. In the first four months following the dropping of the Hiroshima bomb it is estimated that a further 25,000 people died from radiation poisoning and over the following decade cases of cancer, particularly leukaemia, increased. For survivors, ‘hibakusha’ (literally translated as ‘explosion-affected people’) the scars were inevitably both physical and mental. Although hibakusha now receive special state welfare provision and public attention, for many years they and their children were stigmatised. 

Yet, despite the most horrendous circumstances and in remarkable acts of courage and displays of resourcefulness, Hiroshima almost immediately started rebuilding its community. For a city that had, quite literally, been wiped off the map, it required rebuilding in every sense - physically, emotionally and psychologically. Reconstruction proceeded slowly, but in a civic effort, and with some outside help, a new city rose from the ashes. Although the events from that fateful day in August 1945 continue to cast shadows over Hiroshima, and it is unlikely to every fully escape its devastating history, the transformed city which exists today is one of peace and prosperity.

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