You’re near an explosion. You should cover your nose and mouth with a cotton T-shirt or dust mask right away. Covering your nose and mouth can help avoid exposure to toxic particles or radioactive dust.
A dirty bomb is an explosive device that spread radioactive materials over a specific area. As with any bomb, people will likely be killed by the initial blast, and some will develop radiation sickness, but how dangerous the bomb is and whether buildings are contaminated depends on how much radioactive material was used.
If there is an explosion that may be a dirty bomb or other radiological incident, the best shelter is Low down in a basement or cellar. Being sheltered by a thick wall and being below ground offers more protection. Your best option is a window-less room you can seal off, with enough air for several hours. Close windows and doors, and shut down ventilation systems.
After the attack, if you know the direction of the prevailing winds which are likely to carry nuclear fallout, plan an evacuation route perpendicular to the prevailing winds, getting you out of that zone as soon as possible.
Decontaminate by removing clothing and showering.
IF ONLY A ‘Dirty Bomb’ Attack (Not the vastly more devastating nuclear weapon blasts with fallout) You can expect localized and downwind contamination from the explosion and dispersed radioactive materials. If you are near enough to see or hear any local bomb blast, assume that it includes radiological or chemical agents. You should move away from the blast area as quickly as possible. If the wind is blowing toward you from the direction of the blast, travel in a direction that is crosswise or perpendicular to the wind as you move away from the blast area. If possible cover your face with a dust mask or cloth to avoid inhaling potentially radioactive dust. Upon reaching a safe location, remove your outer clothing outside and shower as soon as possible.
If close to a target, your first indication of a nuclear detonation may be with its characteristic blinding bright flash. The first effects you may have to deal with before radioactive fallout arrives, depending on your proximity to it, are blast and thermal energy. Promptly employing the old “Duck & Cover” strategy, immediately upon the first indication of the flash, will save many from avoidable flying debris injuries and minimize thermal burns. Those very close will soon experience tornado strength winds and should quickly dive behind or under any solid object, away from or below windows. Even in the open, laying flat, reduces by eight fold the odds of being hit by any debris. A very large 500 kiloton blast, 2.2 miles away, will arrive about 8 seconds after the detonation flash with a very strong three second wind blast. That delay is even greater further away. That is a lot of time to duck & cover IF alert and you should stay down for 2 minutes. If not near any target ‘ground zero’ you will only, like the vast majority, have to deal with the fallout later.
Avoid radioactive fallout and evacuate the fallout zone quickly. If it is not possible to move out of the path of the radioactive fallout cloud, take shelter as far underground as possible. Try and put as many walls as possible between you and the nuclear radiation coming down as fallout and carried by the shockwave. Find ways to cover skin, nose, and mouth. Decontaminate as soon as possible by removing clothing and showering.
Even if outside the fallout area, still take shelter to avoid any residual radiation. If you’re caught outside when a nuclear weapon is detonated, dive into a ditch or shallow depression in the ground, if you happen to be near one. The shockwave — when it hits a few seconds later — will travel right over the top of you.
The warning signs of chemical attack include people suddenly becoming violently ill, choking or passing out. If you see this, Leave the area as fast as possible. Unlike in an explosion with debris, dust masks or cotton T-shirts won’t protect you in a chemical attack.
Unlike an explosion, a biological attack may not immediately be obvious when germs or other substances that can make you sick are released. You can become sick by inhaling, eating or touching a biological agent. If you see signs of unusual illness, or a biological attack is reported, the safest place to seek shelter is High up in a building. Biological agents will settle on the ground – so the higher up you can get, the better.
If possible, get upwind or seal yourself in a room. Use a gas mask or NBC gear.
BURIED UNDER DEBRIS
In the event of an explosion (or a natural disaster such as a tornado or earthquake), you may become trapped under debris. Tap on a pipe or wall to alert rescuers.