The physical harm caused by the A-bomb included a complex combination of burns from the heat rays and fire (heat damage), broken bones and lacerations sustained from the blast (blast damage), and damage to skin and internal organs caused by radiation. Radiation also complicated the burns and external injuries, producing secondary effects and slowing the healing process during the first four to five months after the bombing. After these acute effects had subsided, a variety of disorders appeared that are now attributed to radiation.
Atomic Bomb Damage And Approximate
The burns resulting from the A-bomb can be classified as primary burns (from direct exposure to the heat rays emitted by the explosion) and secondary burns (from the fires ignited by those heat rays). Practically, the distinction is hard to draw. Many victims suffered both, and damage due to burns was widespread and severe.
Within about 1.2 km of the hypocenter, those exposed in the open to the direct heat rays were burned through the skin and into the tissues below. Internal organs were damaged. The vast majority died immediately or within a few days. Within 2.0 km direct exposure resulted in severe, incapacitating burns. Beyond 3.0 km the burns affected only the surface of the skin, but workers who had removed their shirts to escape the heat of summer were burned noticeably at distances of up to 3.5 km.
In the city, where nearly all standing structures were toppled, thousands were trapped under the debris. Unable to free themselves, they burned to death in the sea of fire ignited by the bomb.
Blast injuries can also be classified as primary injuries (caused by the blast itself) and secondary injuries (caused by collapsing structures). Thousands were hurled through the air, their clothes burned by heat rays and blown instantly to tatters. The skin of those who had been burned by the heat rays was peeled away or left hanging in strips. Glass windows were shattered, and large numbers of victims were covered with hundreds of glass fragments piercing their bodies. Decades later survivors still occasionally had such fragments surgically removed from deep in their flesh; some continue to live with fragments still embedded in them.
The radiation-related symptoms that appeared immediately after the bombing and subsided within approximately five months are called acute effects. Acute effects include digestive tract disorders (nausea, loss of appetite, diarrhea); nervous disorders (headache, delirium, insomnia); fatigue (loss of hair, loss of energy, weakness); bleeding (blood in vomit, blood in urine, blood in stool, purpura); infection (fever, stomatitis, skin infections); blood disorders (loss of red or white blood cells); and reproductive disorders (zoospermia, menstrual disorders).
Acute effects typically began with nausea and vomiting, extreme fatigue, fever, and diarrhea. After approximately two weeks, the victims began losing their hair, a symptom that persisted for one to two weeks. Bleeding and blood disorders were also conspicuous.
Cause of death for those A-bomb victims exposed within two kilometers of the hypocenter and dead by the end of December 1945 is classified according to the type of damage thought to have had the greatest effect. By this classification, about 60% died of heat injuries from the thermal rays and the fires, about 20% were killed by blast injuries, and the remaining 20% were killed by radiation. The thermal rays, blast, and radiation acted synergistically, and most victims died not from a single cause but from the combined effects. Many of those who died of heat(burns) and blast injuries before radiation effects appeared would have died of radiation poisoning.
Long after the acute effects of radiation had subsided, radiation damage continued to produce a wide range of physical problems. Aftereffects, including leukemia, cancer, and many others, appeared two, three, even ten years later. Exposure to radiation in 1945 continues to this day to threaten the health and well-being of the survivors.
Beginning in early 1946, scar tissue covering apparently healed burns began to swell and grow abnormally. Mounds of raised and twisted flesh, called keloids, were found in 50 to 60 percent of those burned by direct exposure to the heat rays within 2.0 km of the hypocenter. Keloids are believed to be related to the effects of radiation. They caused extreme pain, both physically and emotionally.
Leukemia is a malignancy of the blood. Young white blood cells reproduce uncontrollably to such an extent that their function is lost. The victim loses resistance to disease.
Rates of thyroid, breast, lung, salivary gland, and other cancers rose rapidly in the 1960s. Radiation was shown to be an important factor. In some cases, researchers have reported a direct correspondence between distance from hypocenter, probable radiation absorbed, and malignancy rates.
Exposure to the A-bomb had a variety of devastating effects on fetuses exposed in their mothers' womb. Some were born normally and apparently unaffected, but many died in the womb. Those who survived infancy continued to die at a higher rate than unexposed children. One common symptom was microcephaly, a smaller-than-normal skull. In severe cases this symptom is accompanied by mental retardation.
After the bombing, many feared that the radiation would cause genetic effects. Several surveys have as yet failed to discover any harmful influence on the children of survivors. Continued long-term observations and research, however, will be required to rule out such effects.
