Now I am become Death, the destroyer of worlds. - J. Robert Oppenheimer
A nuclear blast is an explosion with intense light and heat, a damaging pressure wave, and widespread radioactive material that can contaminate the air, water, and ground surfaces for miles around. The energy produced by a nuclear explosive is millions of times more per gram and the temperatures reached are in the tens of megakelvins than a conventional explosion. A nuclear device can range from a weapon carried by an intercontinental missile launched by a hostile nation or terrorist organization, to a small portable nuclear devise transported by an individual.
The danger of a massive strategic nuclear attack on the United States is predicted by experts to be less likely today. However, the possibility remains that a terrorist could obtain access to a nuclear weapon. Called improvised nuclear devices (IND), these are generally smaller, less powerful weapons.
The extent, nature and arrival time of these hazards are difficult to predict. The geographical dispersion of hazard effects will be defined by the following:
- Size of the device. A more powerful bomb will produce more distant effects.
- Height above the ground the device was detonated. This will determine the extent of blast effects.
- Nature of the surface beneath the explosion. Some materials are more likely to become radioactive and airborne than others. Flat areas are more susceptible to blast effects.
- Existing meteorological conditions. Wind speed and direction will affect arrival time of fallout; precipitation may wash fallout from the atmosphere.
A nuclear weapon detonated in or above the earth's atmosphere can create an electromagnetic pulse (EMP). An EMP can seriously damage electronic devices connected to power sources or antennas. The damage could range from a minor interruption to actual burnout of components. Most electronic equipment within 1,000 miles of a high-altitude nuclear detonation could be affected. Battery-powered radios with short antennas generally would not be affected. Although an EMP is unlikely to harm most people, it could harm those with pacemakers or other implanted electronic devices.
Before a Nuclear Blast
- To begin preparing, you should build an emergency kit and make a family communications plan.
- Find out from officials if any public buildings in your community have been designated as fallout shelters. If none have been designated, make your own list of potential shelters near your home, workplace and school. These places would include basements or the windowless center area of middle floors in high-rise buildings, as well as subways and tunnels.
- If you live in an apartment building or high-rise, talk to the manager about the safest place in the building for shelDuring periods of heightened threat increase your disaster supplies to be adequate for up to two weeks.
- Keep your car tank at least half full because gas stations rely on electricity to power their pumps.
Taking shelter during a nuclear blast is absolutely necessary. There are two kinds of shelters - blast and fallout. The following describes the two kinds of shelters:
- Blast shelters are specifically constructed to offer some protection against blast pressure, initial radiation, heat and fire. But even a blast shelter cannot withstand a direct hit from a nuclear explosion.
- Fallout shelters do not need to be specially constructed for protecting against fallout. They can be any protected space, provided that the walls and roof are thick and dense enough to absorb the radiation given off by fallout particles.
The three factors for protecting oneself from radiation and fallout are distance, shielding and time.
- Distance - the more distance between you and the fallout particles, the better. An underground area such as a home or office building basement offers more protection than the first floor of a building. A floor near the middle of a high-rise may be better, depending on what is nearby at that level on which significant fallout particles would collect. Flat roofs collect fallout particles so the top floor is not a good choice, nor is a floor adjacent to a neighboring flat roof.
- Shielding - the heavier and denser the materials - thick walls, concrete, bricks, books and earth - between you and the fallout particles, the better.
- Time - fallout radiation loses its intensity fairly rapidly. In time, you will be able to leave the fallout shelter. Radioactive fallout poses the greatest threat to people during the first two weeks, by which time it has declined to about 1 percent of its initial radiation level.
During a Nuclear Blast
- Listen for official information and follow the instructions provided by emergency response personnel. Based on what is known about the threat, you may be asked to take shelter, go to a specific location or evacuate the area.
- If an attack warning is issued, take cover as quickly as you can, below ground if possible, and stay there until instructed to do otherwise. Find the nearest building, preferably built of brick or concrete, and go inside to avoid any radioactive material outside. If better shelter, such as a multi-story building or basement can be reached within a few minutes, go there immediately. Go as far below ground as possible or in the center of a tall building. The goal is to put as many walls and as much concrete, brick and soil between you and the radioactive material outside.
- Radiation levels are extremely dangerous after a nuclear detonation but the levels reduce rapidly. Expect to stay inside for at least 24 hours unless told otherwise by authorities.
If you are caught outside and unable to get inside:
- Do not look at the flash or fireball - it can blind you.
- Take cover behind anything that might offer protection. Lie flat on the ground and cover your head. If the explosion is some distance away, it could take 30 seconds or more for the blast wave to hit.
- Take shelter as soon as you can, even if you are many miles from ground zero where the attack occurred - radioactive fallout can be carried by the winds for hundreds of miles.
- If you were outside during or after the blast. Remove your clothing to keep radioactive material from spreading. Removing the outer layer of clothing can remove up to 90% of radioactive material. If practical, place your contaminated clothing in a plastic bag and seal or tie the bag. Place the bag as far away as possible from humans and animals so that the radiation it gives off does not affect others.
- Get clean as soon as possible, to remove radioactive material that may have settled on your body. When possible, take a shower with lots of soap and water to help remove radioactive contamination. Do not scrub or scratch the skin. Wash your hair with shampoo or soap and water. Do not use conditioner in your hair because it will bind radioactive material to your hair, keeping it from rinsing out easily.
- Gently blow your nose and wipe your eyelids and eyelashes with a clean wet cloth. Gently wipe your ears.
After a Nuclear Blast
Keep listening to the radio and television for news about what to do, where to go and places to avoid.
Decay rates of the radioactive fallout are the same for any size nuclear device. However, the amount of fallout will vary based on the size of the device and its proximity to the ground. Blasts that occur near the earth's surface create much greater amounts of fallout than blasts that occur at higher altitudes. Therefore, it might be necessary for those in the areas with highest radiation levels to shelter for up to a month.
The heaviest fallout would be limited to the area at or downwind from the explosion and 80 percent of the fallout would occur during the first 24 hours.
Nuclear radiation cannot be seen, smelled, or otherwise detected by normal senses. Radiation can only be detected by radiation monitoring devices. Monitoring can project the fallout arrival times, which will be announced through official warning channels. However, any increase in surface build-up of gritty dust and dirt should be a warning for taking protective measures.
