The Nuclear Bombs at Hiroshima and Nagasaki, Japan
The August 1945 bombings of Hiroshima and Nagasaki have been the only use or detonation of nuclear weapons except for testing purposes.The Hiroshima bomb was approximately a 16-kiloton uranium bomb; the Nagasaki bomb was approximately a 21-kiloton plutonium bomb. Both were detonated in the air at an altitude of approximately 1,600 feet. The bomb at Hiroshima destroyed buildings over roughly 4 square miles of the city, and about 60,000 people died immediately from the blast, thermal effects, and fire. Within 2-4 months of the bombings, a total estimated 90,000 to 140,000 deaths occurred in Hiroshim and about 60,000 to 80,000 deaths occurred in Nagasaki,mostly as a result of the immediate effects of the bomb and not to fallout. In a group of 87,000 survivors exposed to radiation who were followed in health studies over the past 60 years,* there were about 430 more cancer deaths than would be expected in a similar but unexposed population (there were 8,000 cancers from all causes compared to an expected 7,600). The additional cancer deaths are attributable to radiation. Nearly half of the people in those studies are still alive.
*The mean dose of those survivors was 16 rad.
The three basic ways people can reduce exposure to radiation are through time, distance, and shielding:
- Time: Decrease the amount of time spent in areas where there is radiation.
- Distance: Increase your distance from a radiation source. Doubling your distance from a point source divides the dose by four. If sheltered in a contaminated area, keep your distance from exterior walls and roofs.
- Shielding: Create a barrier between yourself and the radiation source with a building or vehicle. Buildings—especially those made of brick or concrete—provide considerable shielding from radiation. Exposure is reduced by about 50% inside a one-story building and by about 90% a level below ground.
If there is advanced warning of an impending nuclear attack, people should listen to authorities about whether to evacuate the area or to seek shelter underground as soon as possible.
People outside when a blast occurs should:
- Lie face down on the ground and protect exposed skin (i.e., place hands under the body), and remain flat until the heat and shock waves have passed.
- Cover the mouth and nose with a cloth to filter particulates from the inhaled air.
- Evacuate or find shelter:
- Evacuation: If a cloud of debris is moving toward them, leave the area by a route perpendicular to the path of the fallout.
- If a cloud is not visible or the direction of the fallout is unknown, seek shelter. A basement or center of a high-rise building away from windows or doors would be best.
- If possibly exposed to contaminated dust and debris, remove outer clothing as soon as is reasonable; if possible, shower, wash hair, and change clothes before entering a shelter. Do not scrub harshly or scratch skin.
- Listen for information from emergency responders and authorities.
People sheltering-in-place should:
- Go as far below ground as possible. Shut off ventilation systems and seal doors or windows until the fallout cloud has passed, generally a matter of hours.
- Stay inside until authorities say it is safe to come out.
- Use stored food and drinking water.
- Listen to the local radio or television for official information. Broadcasts may be disrupted for some time as a result of power outages.
For those in the path of the fallout who have survived the initial effects of the explosion, protection from fallout radiation is the most important life-saving measure. Because the material can travel high into the atmosphere, the fallout dispersal pattern cannot be accurately predicted using surface winds. Authorities will advise people to either shelter-in-place or to evacuate.
People advised to evacuate should:
- Listen for information about evacuation routes, temporary shelters, and procedures to follow.
- If there is time before leaving, close and lock windows and doors and turn off air conditioning, vents, fans, and furnace in order to keep radioactive material from being sucked inside.
Medical treatment would be provided to people with burns and injuries and to those suffering from radiation sickness. Treatment for acute radiation syndrome would include the prevention and treatment of infections, stem cell and platelet transfusions, psychological support, and careful observation of skin injury, weight loss, and fever. Exposed and contaminated people can be safely handled by trained responders and medical personnel. If peopleingest or inhale fallout, treatment could include the use of various diluting or mobilizing agents that help rid thebody of radioactive elements. Potassium iodide or KI pills are not a general cure-all; they are only effective in blocking the uptake of inhaled or ingested radioactive iodine into the thyroid gland if taken before or just after inhalation or ingestion. (Radioactive iodine can cause thyroid cancer and disease.)