Safety / Survival / Army Field Manuals / AFM 3-05.70
Survival In Man-Made Hazards
23-1. Prepare yourself to survive in a nuclear environment. Make sure you
know what to expect and how to react to a nuclear hazard.
EFFECTS OF NUCLEAR WEAPONS
23-2. The effects of nuclear weapons are classified as either initial or
residual. Initial effects occur in the immediate area of the explosion and are
hazardous in the first minute after the explosion. Residual effects can last for
days or years and cause death. The principal initial effects are blast and
23-3. Blast is the brief and rapid movement of air away from the explosion's
center and the pressure accompanying this movement. Strong winds accompany the
blast. Blast hurls debris and personnel, collapses lungs, ruptures eardrums,
collapses structures and positions, and causes immediate death or injury with
its crushing effect.
23-4. This effect is the heat and light radiation a nuclear explosion's
fireball emits. Light radiation consists of both visible light and ultraviolet
and infrared light. Thermal radiation produces extensive fires, skin burns, and
23-5. Nuclear radiation breaks down into two categories. The effects can be
initial radiation and residual radiation.
23-6. Initial nuclear radiation consists of intense gamma rays and neutrons
produced during the first minute after the explosion. This radiation causes
extensive damage to cells throughout the body. Radiation damage may cause
headaches, nausea, vomiting, diarrhea, and even death, depending on the
radiation dose received. The major problem in protecting yourself against the
initial radiation's effects is that you may have received a lethal or
incapacitating dose before taking any protective action. Personnel exposed to
lethal amounts of initial radiation may well have been killed or fatally injured
by blast or thermal radiation.
23-7. Residual radiation consists of all radiation produced after 1 minute
from the explosion. It has more effect on you than initial radiation. A
discussion of residual radiation takes place in a subsequent paragraph.
TYPES OF NUCLEAR BURSTS
23-8. There are three types of nuclear bursts: subsurface burst, airburst,
and surface burst. The type of burst directly affects your chances of survival.
A subsurface burst occurs completely underground or underwater. Its effects
remain beneath the surface or in the immediate area where the surface collapses
into a crater over the burst's location. Subsurface bursts cause you little or
no radioactive hazard unless you enter the immediate area of the crater.
23-9. An airburst occurs in the air above its intended target. The airburst
provides the maximum radiation effect on the target and is, therefore, most
dangerous to you in terms of immediate nuclear effects.
23-10. A surface burst occurs on the ground or water surface. Large amounts
of fallout result, with serious long-term effects for you. This type of burst is
your greatest nuclear hazard.
23-11. Most injuries in the nuclear environment result from the initial
nuclear effects of the detonation. These injuries are classed as blast, thermal,
or radiation injuries. Further radiation injuries may occur if you do not take
proper precautions against fallout. Individuals in the area near a nuclear
explosion will probably suffer a combination of all three types of injuries.
23-12. Blast injuries produced by nuclear weapons are similar to those caused
by conventional high-explosive weapons. Blast overpressure can collapse lungs
and rupture internal organs. Projectile wounds occur as the explosion's force
hurls debris at you. Large pieces of debris striking you will cause fractured
limbs or massive internal injuries. Blast overpressure may throw you long
distances, and you will suffer severe injury upon impact with the ground or
other objects. Substantial cover and distance from the explosion are the best
protection against blast injury. Cover blast injury wounds as soon as possible
to prevent the entry of radioactive dust particles.
23-13. The heat and light the nuclear fireball emits cause thermal injuries.
First-, second-, or third-degree burns may result. Flash blindness also occurs.
This blindness may be permanent or temporary depending on the degree of exposure
of the eyes. Substantial cover and distance from the explosion can prevent
thermal injuries. Clothing will provide significant protection against thermal
injuries. Cover as much exposed skin as possible before a nuclear explosion.
First aid for thermal injuries is the same as first aid for burns. Cover open
burns (second- or third-degree) to prevent the entry of radioactive particles.
Wash all burns before covering.
23-14. Neutrons, gamma radiation, alpha radiation, and beta radiation cause
radiation injuries. Neutrons are high-speed, extremely penetrating particles
that actually smash cells within your body. Gamma radiation is similar to X rays
and is also highly penetrating radiation. During the initial fireball stage of a
nuclear detonation, initial gamma radiation and neutrons are the most serious
threat. Beta and alpha radiation are radioactive particles normally associated
with radioactive dust from fallout. They are short-range particles. You can
easily protect yourself against them if you take precautions. See "Bodily
Reactions to Radiation," below, for the symptoms of radiation injuries.
23-15. Residual radiation is all radiation emitted after 1 minute from the
instant of the nuclear explosion. Residual radiation consists of induced
radiation and fallout.
23-16. This term describes a relatively small, intensely radioactive area
directly underneath the nuclear weapon's fireball. The irradiated earth in this
area will remain highly radioactive for an extremely long time. You should not
travel into an area of induced radiation.
23-17. Fallout consists of radioactive soil and water particles, as well as
weapon fragments. During a surface detonation, or if an airburst's nuclear
fireball touches the ground, large amounts of soil and water are vaporized along
with the bomb's fragments, and forced upward to altitudes of 25,000 meters
(82,000 feet) or more. When these vaporized contents cool, they can form more
than 200 different radioactive products. The vaporized bomb contents condense
into tiny radioactive particles that the wind carries until they fall back to
earth as radioactive dust. Fallout particles emit alpha, beta, and gamma
radiation. Alpha and beta radiation are relatively easy to counteract, and
residual gamma radiation is much less intense than the gamma radiation emitted
during the first minute after the explosion. Fallout is your most significant
radiation hazard, provided you have not received a lethal radiation dose from
the initial radiation.
BODILY REACTIONS TO RADIATION
23-18. The effects of radiation on the human body can be broadly classed as
either chronic or acute. Chronic effects are those that occur some years after
exposure to radiation. Examples are cancer and genetic defects. Chronic effects
are of minor concern insofar as they affect your immediate survival in a
radioactive environment. On the other hand, acute effects are of primary
importance to your survival. Some acute effects occur within hours after
exposure to radiation. These effects result from the radiation's direct physical
damage to tissue. Radiation sickness and beta burns are examples of acute
effects. Radiation sickness symptoms include nausea, diarrhea, vomiting,
fatigue, weakness, and loss of hair. Penetrating beta rays cause radiation
burns; the wounds are similar to fire burns.
23-19. The extent of body damage depends mainly on the part of the body
exposed to radiation and how long it was exposed, as well as its ability to
recover. The brain and kidneys have little recovery capability. Other parts
(skin and bone marrow) have a great ability to recover from damage. Usually, a
dose of 600 centigrays (cGy) to the entire body will result in almost certain
death. If only your hands received this same dose, your overall health would not
suffer much, although your hands would suffer severe damage.
External and Internal Hazards
23-20. An external or internal hazard can cause body damage. Highly
penetrating gamma radiation or the less penetrating beta radiation that causes
burns can cause external damage. The entry of alpha or beta radiation-emitting
particles into the body can cause internal damage. The external hazard produces
overall irradiation and beta burns. The internal hazard results in irradiation
of critical organs such as the gastrointestinal tract, thyroid gland, and bone.
A very small amount of radioactive material can cause extreme damage to these
and other internal organs. The internal hazard can enter the body either through
consumption of contaminated water or food or by absorption through cuts or
abrasions. Material that enters the body through breathing presents only a minor
hazard. You can greatly reduce the internal radiation hazard by using good
personal hygiene and carefully decontaminating your food and water.
23-21. The symptoms of radiation injuries include nausea, diarrhea, and
vomiting. The severity of these symptoms is due to the extreme sensitivity of
the gastrointestinal tract to radiation. The severity of the symptoms and the
speed of onset after exposure are good indicators of the degree of radiation
damage. The gastrointestinal damage can come from either the external or the
internal radiation hazard.
COUNTERMEASURES AGAINST PENETRATING EXTERNAL RADIATION
23-22. Knowledge of the radiation hazards discussed earlier is extremely
important in surviving in a fallout area. It is also critical to know how to
protect yourself from the most dangerous form of residual
radiation—penetrating external radiation.
23-23. The means you can use to protect yourself from penetrating external
radiation are time, distance, and shielding. You can reduce the level of
radiation and help increase your chance of survival by controlling the duration
of exposure. You can also get as far away from the radiation source as possible.
Finally, you can place some radiation-absorbing or shielding material between
you and the radiation.
23-24. Time is important, in two ways, when you are in a survival situation.
First, radiation dosages are cumulative. The longer you are exposed to a
radioactive source, the greater the dose you will receive. Obviously, spend as
little time in a radioactive area as possible. Second, radioactivity decreases
or decays over time. This concept is known as radioactive half-life.
Thus, a radioactive element decays or loses half of its radioactivity within a
certain time. The rule of thumb for radioactivity decay is that it decreases in
intensity by a factor of ten for every sevenfold increase in time following the
peak radiation level. For example, if a nuclear fallout area had a maximum
radiation rate of 200 cGy per hour when fallout is complete, this rate would
fall to 20 cGy per hour after 7 hours; it would fall still further to 2 cGy per
hour after 49 hours. Even an untrained observer can see that the greatest hazard
from fallout occurs immediately after detonation, and that the hazard decreases
quickly over a relatively short time. You should try to avoid fallout areas
until the radioactivity decays to safe levels. If you can avoid fallout areas
long enough for most of the radioactivity to decay, you enhance your chance of
23-25. Distance provides very effective protection against penetrating gamma
radiation because radiation intensity decreases by the square of the distance
from the source. For example, if exposed to 1,000 cGy of radiation standing 30
centimeters (12 inches) from the source, at 60 centimeters (24 inches), you
would only receive 250 cGy. Thus, when you double the distance, radiation
decreases to (0.5)2 or 0.25 the amount. While this formula is valid
for concentrated sources of radiation in small areas, it becomes more
complicated for large areas of radiation such as fallout areas.
23-26. Shielding is the most important method of protection from penetrating
radiation. Of the three countermeasures against penetrating radiation, shielding
provides the greatest protection and is the easiest to use under survival
conditions. Therefore, it is the most desirable method. If shielding is not
possible, use the other two methods to the maximum extent practical.
23-27. Shielding actually works by absorbing or weakening the penetrating
radiation, thereby reducing the amount of radiation reaching your body. The
denser the material, the better the shielding effect. Lead, iron, concrete, and
water are good examples of shielding materials.
Special Medical Aspects
23-28. The presence of fallout material in your area requires slight changes
in first aid procedures. You must cover all wounds to prevent contamination and
the entry of radioactive particles. You must first wash burns of beta radiation,
then treat them as ordinary burns. Take extra measures to prevent infection.
Your body will be extremely sensitive to infections due to changes in your blood
chemistry. Pay close attention to the prevention of colds or respiratory
infections. Rigorously practice personal hygiene to prevent infections. Cover
your eyes with improvised goggles to prevent the entry of particles.
23-29. As stated earlier, the shielding material's effectiveness depends on
its thickness and density. An ample thickness of shielding material will reduce
the level of radiation to negligible amounts.
23-30. The primary reason for finding and building a shelter is to get
protection against the high-intensity radiation levels of early gamma fallout as
fast as possible. Five minutes to locate the shelter is a good guide. Speed in
finding shelter is absolutely essential. Without shelter, the dosage received in
the first few hours will exceed that received during the rest of a week in a
contaminated area. The dosage received in this first week will exceed the dosage
accumulated during the rest of a lifetime spent in the same contaminated area.
23-31. The thickness required to weaken gamma radiation from fallout is far
less than that needed to shield against initial gamma radiation. Fallout
radiation has less energy than a nuclear detonation's initial radiation. For
fallout radiation, a relatively small amount of shielding material can provide
adequate protection. Figure 23-1 shows the thickness of
various materials needed to reduce residual gamma radiation transmission by 50
Figure 23-1. Materials to Reduce Gamma Radiation
23-32. The principle of half-value layer thickness is useful in
understanding the absorption of gamma radiation by various materials. According
to this principle, if 5 centimeters (2 inches) of brick reduce the gamma
radiation level by one-half, adding another 5 centimeters (2 inches) of brick
(another half-value layer) will reduce the intensity by another half, namely, to
one-fourth the original amount. Fifteen centimeters (6 inches) will reduce gamma
radiation fallout levels to one-eighth its original amount, 20 centimeters (8
inches) to one-sixteenth, and so on. Thus, a shelter protected by 1 meter (3
feet) of dirt would reduce a radiation intensity of 1,000 cGy per hour on the
outside to about 0.5 cGy per hour inside the shelter.
23-33. Terrain that provides natural shielding and easy shelter construction
is the ideal location for an emergency shelter. Good examples are ditches,
ravines, rocky outcropping, hills, and riverbanks. In level areas without
natural protection, dig a fighting position or slit trench.
23-34. When digging a trench, work from inside the trench as soon as it is
large enough to cover part of your body thereby not exposing all your body to
radiation. In open country, try to dig the trench from a prone position,
stacking the dirt carefully and evenly around the trench. On level ground, pile
the dirt around your body for additional shielding. Depending upon soil
conditions, shelter construction time will vary from a few minutes to a few
hours. If you dig as quickly as possible, you will reduce the dosage you
23-35. While an underground shelter covered by 1 meter (3 feet) or more of
earth provides the best protection against fallout radiation, the following
unoccupied structures (in order listed) offer the next best protection:
Caves and tunnels covered by more than 1 meter (3 feet) of earth.
Storm or storage cellars.
Basements or cellars of abandoned buildings.
Abandoned buildings made of stone or mud.
23-36. It is not mandatory that you build a roof on your shelter. Build one
only if the materials are readily available with only a brief exposure to
outside contamination. If building a roof would require extended exposure to
penetrating radiation, it would be wiser to leave the shelter roofless. A roof's
sole function is to reduce radiation from the fallout source to your body.
Unless you use a thick roof, a roof provides very little shielding.
23-37. You can construct a simple roof from a poncho anchored down with dirt,
rocks, or other refuse from your shelter. You can remove large particles of dirt
and debris from the top of the poncho by beating it off from the inside at
frequent intervals. This cover will not offer shielding from the radioactive
particles deposited on the surface, but it will increase the distance from the
fallout source and keep the shelter area from further contamination.
Shelter Site Selection and Preparation
23-38. To reduce your exposure time and thereby reduce the dosage received,
remember the following factors when selecting and setting up a shelter:
Where possible, seek a crude, existing shelter that you can improve. If
none is available, dig a trench.
Dig the shelter deep enough to get good protection, then enlarge it as
required for comfort.
Cover the top of the fighting position or trench with any readily
available material and a thick layer of earth, if you can do so without
leaving the shelter. While a roof and camouflage are both desirable, it is
probably safer to do without them than to expose yourself to radiation
outside your fighting position.
While building your shelter, keep all parts of your body covered with
clothing to protect it against beta burns.
Clean the shelter site of any surface deposit using a branch or other
object that you can discard. Do this cleaning to remove contaminated
materials from the area you will occupy. The cleaned area should extend at
least 1.5 meters (5 feet) beyond your shelter's area.
Decontaminate any materials you bring into the shelter. These materials
include grass or foliage that you use as insulation or bedding, and your
outer clothing (especially footgear). If the weather permits and you have
heavily contaminated outer clothing, you may want to remove it and bury it
under a foot of earth at the end of your shelter. You may retrieve it later
(after the radioactivity decays) when leaving the shelter. If the clothing
is dry, you may decontaminate it by beating or shaking it outside the
shelter's entrance to remove the radioactive dust. You may use any body of
water, even though contaminated, to rid materials of excess fallout
particles. Simply dip the material into the water and shake it to get rid of
the excess water. Do not wring it out, this action will trap the particles.
If possible and without leaving the shelter, wash your body thoroughly
with soap and water, even if the water on hand may be contaminated. This
washing will remove most of the harmful radioactive particles that are
likely to cause beta burns or other damage. If water is not available, wipe
your face and any other exposed skin surface to remove contaminated dust and
dirt. You may wipe your face with a clean piece of cloth or a handful of
uncontaminated dirt. You get this uncontaminated dirt by scraping off the
top few inches of soil and using the "clean" dirt.
Upon completing the shelter, lie down, keep warm, and sleep and rest as
much as possible while in the shelter.
When not resting, keep busy by planning future actions, studying your
maps, or making the shelter more comfortable and effective.
Don't panic if you experience nausea and symptoms of radiation sickness.
Your main danger from radiation sickness is infection. There is no first aid
for this sickness. Resting, drinking fluids, taking any medicine that
prevents vomiting, maintaining your food intake, and preventing additional
exposure will help avoid infection and aid recovery. Even small doses of
radiation can cause these symptoms, which may disappear in a short time.
23-39. The following timetable provides you with the information needed to
avoid receiving a serious dosage and still let you cope with survival problems:
Complete isolation from 4 to 6 days following delivery of the last
A very brief exposure to get water on the third day is permissible, but
exposure should not exceed 30 minutes.
One exposure of not more than 30 minutes on the seventh day.
One exposure of not more than 1 hour on the eighth day.
Exposure of 2 to 4 hours from the ninth day through the twelfth day.
Normal operation, followed by rest in a protected shelter, from the
thirteenth day on.
In all instances, make your exposures as brief as possible. Consider only
mandatory requirements as valid reasons for exposure. Decontaminate at every
23-40. The times given above are conservative. If forced to move after the
first or second day, you may do so. Make sure that the exposure is no longer
than absolutely necessary.
23-41. In a fallout-contaminated area, available water sources may be
contaminated. If you wait at least 48 hours before drinking any water to allow
radioactive decay to take place and select the safest possible water source, you
will greatly reduce the danger of ingesting harmful amounts of radioactivity.
23-42. Although many factors (wind direction, rainfall, sediment) will
influence your choice in selecting water sources, consider the following
Safest Water Sources
23-43. Water from springs, wells, or other underground sources that undergo
natural filtration will be your safest sources. Any water found in the pipes or
containers of abandoned houses or stores will also be free from radioactive
particles. This water will be safe to drink, although you will have to take
precautions against bacteria in the water.
23-44. Snow taken from 15 centimeters (6 inches) or more below the surface
during the fallout is also a safe source of water.
Streams and Rivers
23-45. Water from streams and rivers will be relatively free from fallout
within several days after the last nuclear explosion because of dilution. If
possible, filter such water before drinking to get rid of radioactive particles.
The best filtration method is to dig sediment holes or seepage basins along the
side of a water source. The water will seep laterally into the hole through the
intervening soil that acts as a filtering agent and removes the contaminated
fallout particles that settled on the original body of water. This method can
remove up to 99 percent of the radioactivity in water. You must cover the hole
in some way to prevent further contamination. See Figure
6-9 for an example of a water filter.
23-46. Water from lakes, pools, ponds, and other standing sources is likely
to be heavily contaminated; though most of the heavier, long-lived radioactive
isotopes will settle to the bottom. Use the settling technique to purify this
water. First, fill a bucket or other deep container three-fourths full with
contaminated water. Then take dirt from a depth of 10 centimeters (4 inches) or
more below the ground surface and stir it into the water. Use about 2.5
centimeters (1 inch) of dirt for every 10 centimeters (4 inches) of water. Stir
the water until you see most dirt particles suspended in the water. Let the
mixture settle for at least 6 hours. The settling dirt particles will carry most
of the suspended fallout particles to the bottom and cover them. You can then
dip out the clear water. Purify this water using a filtration device.
23-47. As an additional precaution against disease, treat all water with
water purification tablets from your survival kit or boil it.
23-48. Obtaining edible food in a radiation-contaminated area is a serious
but not insurmountable problem. You need to follow a few special procedures in
selecting and preparing rations and local foods for use. Since secure packaging
protects your combat rations, they will be perfectly safe for use. Supplement
your rations with any food you can find on trips outside your shelter.
Abandoned buildings may have stores of processed foods. They are safe for use
after decontaminating them. Canned and packaged foods should have containers or
wrappers removed or washed free of fallout particles. These processed foods also
include food stored in any closed container and food stored in protected areas
(such as cellars). All such foods must be washed before eating or handling them.
23-49. If little or no processed food is available in your area, you may have
to supplement your diet with local food sources. Animals and plants are local
Animals—A Food Source
23-50. Assume that all animals, regardless of their habitat or living
conditions, were exposed to radiation. The effects of radiation on animals are
similar to those on humans. Thus, most of the wild animals living in a fallout
area are likely to become sick or die from radiation during the first month
after the nuclear explosion. Although animals may not be free from harmful
radioactive materials, you can and must use them in survival conditions as a
food source if other foods are not available. With careful preparation and by
following several important principles, animals can be safe food sources.
23-51. First, do not eat an animal that appears to be sick. It may have
developed a bacterial infection because of radiation poisoning. Contaminated
meat, even if thoroughly cooked, could cause severe illness or death if eaten.
23-52. Carefully skin all animals to prevent any radioactive particles on the
skin or fur from entering the body. Do not eat meat close to the bones and
joints as an animal's skeleton contains over 90 percent of the radioactivity.
However, the remaining animal muscle tissue will be safe to eat. Before cooking
it, cut the meat away from the bone, leaving at least a 3-millimeter (1/8-inch)
thickness of meat on the bone. Discard all internal organs (heart, liver, and
kidneys) since they tend to concentrate beta and gamma radioactivity.
23-53. Cook all meat until it is very well done. To be sure the meat is well
done, cut it into less than 13-millimeter-thick (4 1/2-inch-thick) pieces before
cooking. Such cuts will also reduce cooking time and save fuel.
23-54. The extent of contamination in fish and aquatic animals will be much
greater than that of land animals. This is also true for water plants,
especially in coastal areas. Use aquatic food sources only in conditions of
23-55. All eggs, even if laid during the period of fallout, will be safe to
eat. Completely avoid milk from any animals in a fallout area because animals
absorb large amounts of radioactivity from the plants they eat.
Plants—A Food Source
23-56. Plant contamination occurs by the accumulation of fallout on their
outer surfaces or by absorption of radioactive elements through their roots.
Your first choice of plant food should be vegetables such as potatoes, turnips,
carrots, and other plants whose edible portion grows underground. These are the
safest to eat once you scrub them and remove their skins.
23-57. Second, in order of preference, are those plants with edible parts
that you can decontaminate by washing and peeling their outer surfaces. Examples
are bananas, apples, tomatoes, prickly pears, and other such fruits and
23-58. Any smooth-skinned vegetable, fruit, or plant that you cannot easily
peel or effectively decontaminate by washing will be your third choice of
23-59. The effectiveness of decontamination by scrubbing is inversely
proportional to the roughness of the fruit's surface. Smooth-surfaced fruits
will lose 90 percent of their contamination after washing, but rough-surfaced
plants will lose only about 50 percent.
23-60. Eat rough-surfaced plants (such as lettuce) only as a last resort
because you cannot effectively decontaminate them by peeling or washing. Other
difficult foods to decontaminate by washing with water include dried fruits
(figs, prunes, peaches, apricots, pears) and soybeans.
23-61. In general, you can use any plant food that is ready for harvest if
you can effectively decontaminate it. However, growing plants can absorb some
radioactive materials through their leaves as well as from the soil, especially
if rains have occurred during or after the fallout period. Avoid using these
plants for food except in an emergency.