As the atom bomb exploded it created a fireball that was as hot as the centre of the sun. On the ground it created a firestorm which burned uncontrollably for six hours. Everything within two kilometres that could burn, including people, burnt. Anyone out in the open as far away as three and a half kilometres had their skin burnt. The fire raged, and people burnt, and there was no one to put out the fire. Even if there had been, they would have been helpless. The explosion had destroyed all the water pipes.
Buildings disintegrated from the shock wave that followed the heat. Almost nothing was left standing. Half a kilometre away from the explosion even the strongest buildings collapsed, their walls crushed by the shock wave. Even as far away as two and a half kilometres all the buildings were so smashed up that they were unusable. The city, now only rubble, became its own map.
The firestorm and the blast could have been produced by conventional bombs. It would have taken about 300 tonnes of high explosives and nearly a thousand tonnes of incendiary bombs. But what these bombs could not have done was produce radiation. This killed people immediately; there was nausea and then vomiting, loss of appetite, fever, diarrhoea and spontaneous bleeding. Hair started to fall out, and the bleeding increased, blood seeped form every orifice of the body. Death, when it came, was a relief. There was no way to treat these living dead. No one knew how to treat such radiation injuries. There were no hospitals where they could have been treated. There were few doctors left alive and able to take care of themselves, never mind patients – the patients already in hospitals died. The complete destruction of the city's administration meant that there was no one to count the dead.
The radiation from the explosion meant that people kept on dying. It was a slow lingering death. Radiation made the bones of the living radioactive and killed them from the inside. Among the survivors, the number of people with leukaemia increased gradually, reaching a peak nearly 10 years after the bomb was used. Other cancers also increased; especially cancer of the thyroid, breast and lung.