Nuclear explosions have intense light and heat, a damaging pressure wave, and widespread radioactive material that can contaminate the air, water, and ground for miles around. The blast causes deadly effects when detonated, including blinding light, intense heat (thermal radiation), initial nuclear radiation, fires started by the heat pulse and secondary fires caused by the destruction.
A nuclear device can range from a weapon carried by a missile, to a small portable device transported by an individual. Improvised nuclear devices (INDs) are generally smaller, less powerful weapons. Regardless of size, a nuclear weapon is a device that uses a nuclear reaction to create an explosion.
Fallout is radioactive dirt and debris that can fall to the earth and cause sickness to those who come into contact with it.
Fallout is most dangerous in the first few hours after the detonation when it is giving off the highest levels of radiation. It takes time for fallout to arrive back to ground level, often more than 15 minutes for areas outside of the immediate blast damage zones. This is enough time for you to be able to prevent significant radiation exposure by following a few simple steps.
While experts may predict that a nuclear attack is less likely than other potential disasters, it is still important to know the lifesaving actions that you can take to protect yourself in the event of a nuclear explosion.
- Build an emergency go kit, which includes items like non-perishable food, water, a battery-powered or hand-crank radio, extra flashlights and batteries. You may want to prepare a kit for your workplace and a portable kit to keep in your car in case you are told to evacuate. If possible, store supplies for three or more days.
- Make a family communication plan. Your family may not be together when disaster strikes, so it is important to know how you will contact one another, how you will get back together and what you will do in case of an emergency.
Know the factors for protecting yourself from radiation: 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.
- 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. 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. Identify the best shelter location near where you spend a lot of time, such as home, work and school. The best locations are underground and in the middle of larger buildings.
- If warned of an imminent attack, immediately get inside the nearest building and move away from windows. This will help provide protection from the blast, heat and radiation of the detonation. Listen for official information and follow the instructions provided by emergency response personnel.
- If you are outdoors when a detonation occurs take cover from the blast behind anything that might offer protection. Lie face down to protect exposed skin from the heat and flying debris. If you are in a vehicle, stop safely, and duck down within the vehicle. Do not look at the flash or fireball—it can blind you. After the shock wave passes, get inside the nearest, best shelter location for protection from potential fallout. You will have 10 minutes or more to find an adequate shelter.
- Be inside before the fallout arrives. The highest outdoor radiation levels from fallout occur immediately after the fallout arrives and then decrease with time. Put as many walls and as much concrete, brick and soil between you and the radioactive material outside
- Stay where you are, even if you are separated from your family. Inside is the safest place for all people in the impacted area. It can save your life.
- Stay tuned for updated instructions from emergency response officials. If advised to evacuate, listen for information about routes, shelters, and procedures.
- Expect to stay inside for at least 24 hours unless told otherwise by authorities.
- If you have evacuated, do not return until you are told it is safe to do so by local officials.
- Take cover behind anything that might offer protection.
- Radiation levels are extremely dangerous after a nuclear explosion, but the levels reduce rapidly.
- Radiation cannot be seen, smelled, or otherwise detected by human senses.
Immediately after you are inside shelter, if you may have been outside after the fallout arrived:
- Remove your outer layer of contaminated clothing to remove fallout and radiation from your body. Removing the outer layer of clothing can remove up to 90 percent of radioactive material.
- Take a shower or wash with soap and water to remove fallout from any skin or hair that was not covered. If you cannot wash or shower, use a wipe or clean wet cloth to wipe any skin or hair that was not covered. Do not scrub or scratch the skin or use conditioner because it will bind radioactive material to your hair.
- Clean any pets that were outside after the fallout arrived. Gently brush your pet’s coat to remove any fallout particles and wash your pet with soap and water, if available.
- It is safe to eat or drink packaged food items or items that were inside a building. Do not consume food or liquids that were outdoors uncovered and may be contaminated by fallout.