Nuclear Blast
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. 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. All nuclear devices cause deadly
effects when exploded, including blinding light, intense heat (thermal radiation), initial
nuclear radiation, blast, fires started by the heat pulse, and secondary fires caused by the

Hazards of Nuclear Devices
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
• Existing meteorological conditions. Wind speed and direction will affect arrival time of
fallout; precipitation may wash fallout from the atmosphere.

Radioactive Fallout
Even if individuals are not close enough to the nuclear blast to be affected by the direct
impacts, they may be affected by radioactive fallout. Any nuclear blast results in some
fallout. Blasts that occur near the earth’s surface create much greater amounts of fallout
than blasts that occur at higher altitudes. This is because the tremendous heat produced
from a nuclear blast causes an up-draft of air that forms the familiar mushroom cloud.
When a blast occurs near the earth’s surface, millions of vaporized dirt particles also are
drawn into the cloud. As the heat diminishes, radioactive materials that have vaporized
condense on the particles and fall back to Earth. The phenomenon is called radioactive
fallout. This fallout material decays over a long period of time, and is the main source of
residual nuclear radiation.
Fallout from a nuclear explosion may be carried by wind currents for hundreds of miles if
the right conditions exist. Effects from even a small portable device exploded at ground
level can be potentially deadly.
Nuclear radiation cannot be seen, smelled, or otherwise detected by normal senses.
Radiation can only be detected by radiation monitoring devices. This makes radiological
emergencies different from other types of emergencies, such as floods or hurricanes.
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.

Radioactive Fallout
In addition to other effects, a nuclear weapon detonated in or above the earth’s
atmosphere can create an electromagnetic pulse (EMP), a high-density electrical field. An
EMP acts like a stroke of lightning but is stronger, faster, and shorter. An EMP can
seriously damage electronic devices connected to power sources or antennas. This
includes communication systems, computers, electrical appliances, and automobile or
aircraft ignition systems. 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.
How can I protect myself from a nuclear blast?
• Protection from a nuclear blast
• What to do before a nuclear blast
• What to do during a nuclear blast
• What to do after a nuclear blast

Protection from a Nuclear Blast
The danger of a massive strategic nuclear attack on the United States is predicted by
experts to be less likely today. However, terrorism, by nature, is unpredictable.
If there were threat of an attack, people living near potential targets could be advised to
evacuate or they could decide on their own to evacuate to an area not considered a likely
target. Protection from radioactive fallout would require taking shelter in an underground
area or in the middle of a large building.
In general, potential targets include:
• Strategic missile sites and military bases.
• Centers of government such as Washington, DC, and state capitals.
• Important transportation and communication centers.
• Manufacturing, industrial, technology, and financial centers.
• Petroleum refineries, electrical power plants, and chemical plants.
• Major ports and airfields.
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.
Remember that any protection, however temporary, is better than none at all, and the
more shielding, distance, and time you can take advantage of, the better.

Before a Nuclear Blast
To prepare for a nuclear blast, you should do the following:
• 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
• If you live in an apartment building or high-rise, talk to the manager about the safest
place in the building for sheltering and about providing for building occupants until it is
safe to go out.
• During periods of increased threat increase your disaster supplies to be adequate for up
to two weeks.
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

During a Nuclear Blast
The following are guidelines for what to do in the event of a nuclear explosion.
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.
• Listen for official information and follow instructions.
If you are caught outside and unable to get inside immediately:
• 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.
Remember the three protective factors: Distance, shielding, and time.

After a Nuclear Blast
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. 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.
People in most of the areas that would be affected could be allowed to come out of shelter
within a few days and, if necessary, evacuate to unaffected areas.
Remember the following when returning home:
• Keep listening to the radio and television for news about what to do, where to go, and
places to avoid.
• Stay away from damaged areas. Stay away from areas marked “radiation hazard” or
“HAZMAT.” Remember that radiation cannot be seen, smelled, or otherwise detected by
human senses.
How Much Radiation Can You Take
We all know radiation is dangerous and can have severe effects on the body; we only need to look at the
aftermath of the Chernobyl disaster or the atomic bombs dropped over Hiroshima and Nagasaki to see their horrific
effects. But how much radiation can a body take? Can you recover? And what are the signs and symptoms of
radiation poisoning?
The first thing you have to understand about radiation is you can’t see it, smell it or taste it. The only time it will be
visible is the fallout after a nuclear blast. This dust will have the appearance of dusty snow. Apart from that you
won’t have any idea your in a radioactive zone without proper detection equipment.

So just how much radiation can the human body withstand? Here is a list giving you a basic idea of what to expect
at what levels. All measurements here are calculated in RADS which is short for radiation absorbed dose.

5 RADS and under - No visible symptoms

5 to 50 RADS - Temporarily decreased red blood cell count (you’ll survive but will fee pretty ill)

50 to 100 RADS - Decreased production of immunity cells, you will be susceptible to infections, nausea, headache,
and vomiting are common. With treatment you will survive.

150 to 300 RADS - Up to 35 percent of those who are exposed to radiation up to this level will die within 30 days.
They will suffer nausea, vomiting and will lose all their hair

300 to 400 RADS - At this point your chances drop to 50/50 fatality rate after 30 days. Like the last level all the
same symptoms will happen but with the addition of uncontrollable bleeding in the mouth, under the skin, and the

400 to 600 RADS - You have a 60 percent fatality rate after 30 days, symptoms like those at the 150 to 300 level
starts to become visible in a couple hours after exposure

600 to 1000 RADS - Almost 100 percent fatality rate after 14 days. Your intestinal tissue will be severely damaged
and almost all bone marrow will be destroyed

1200 to 2000 RADS - 100 percent fatality with immediate symptoms after exposure

2000 RADS and over - Symptoms set in instantly upon contact then will cease for several days, giving the victim a
“false hope” that they are recovering. Suddenly gastrointestinal cells are destroyed and death will begin with
delirium since the brain can’t function normally and starts to shut down.