With the recent threats of terrorism, many
Californians have expressed concern about the likelihood and effects of a
nuclear blast. This fact sheet was developed to describe what happens when a
nuclear blast occurs, the possible health effects and what you can do to protect
yourself in this type of emergency.
What Is a Nuclear
A nuclear blast, produced by the explosion of a
nuclear bomb (sometimes called a nuclear detonation), involves the joining or
splitting of atoms (called fusion and fission) to produce an intense pulse or
wave of heat, light, air pressure and radiation. The bombs dropped on Hiroshima
and Nagasaki, Japan, at the end of World War II produced nuclear blasts.
When a nuclear device is exploded, a large
fireball is created. Everything inside of this fireball vaporizes, including
soil and water, and is carried upwards. This creates the mushroom cloud that we
associate with a nuclear blast, detonation or explosion. Radioactive material
from the nuclear device mixes with the vaporized material in the mushroom cloud.
As this vaporized material cools, it becomes condensed and forms particles, such
as dust. The condensed radioactive material then falls back to the earth. This
is what is known as fallout. Because fallout is in the form of particles, it can
be carried long distances on wind currents and end up miles from the site of the
explosion. Fallout is radioactive and can cause contamination of anything on
which it lands, including food and water supplies.
What Are the Effects of
a Nuclear Blast?
The effects on a person from a nuclear blast will
depend on the size of the bomb and the distance the person is from the
explosion. Nuclear blasts would likely cause great destruction, death, injury
and have a wide area of impact.
In a nuclear blast, injury or death may occur as a
result of the blast itself or as a result of debris thrown from the blast.
People may experience moderate to severe skin burns, depending on their distance
from the blast site. Those who look directly at the blast could experience eye
damage ranging from temporary blindness to severe burns on the retina.
Individuals near the blast site would be exposed to high levels of radiation and
could develop symptoms of radiation sickness (called acute radiation syndrome,
or ARS). While severe burns would appear in minutes, other health effects might
take days or weeks to appear. These effects range from mild, such as skin
reddening, to severe effects such as cancer or death, depending on the amount of
radiation absorbed by the body (the dose), the type of radiation, the route of
exposure and the length of time of the exposure.
People may experience two types of exposure from
radioactive materials from a nuclear blast: external exposure and internal
exposure. External exposure would occur when people were exposed to radiation
outside of their bodies from the blast or its fallout. Internal exposure would
occur when people ate food or breathed air that was contaminated with
radioactive fallout. Both internal and external exposure from fallout could
occur miles away from the blast site. Exposure to very large doses of external
radiation may cause death within a few days or months. External exposure to
lower doses of radiation and internal exposure from breathing or eating food
contaminated with radioactive fallout may lead to an increased risk of
developing cancer and other health effects.
How Can I Protect My
Family and Myself During a Nuclear Blast?
In the event of a nuclear blast, a national
emergency response plan would be activated and would include federal, state and
local agencies. Following are some steps recommended by the World Health
Organization (WHO) if a nuclear blast occurs:
If You Are Near the
Blast When it Occurs
Turn away and close and cover your eyes to prevent damage
to your sight.
Drop to the ground face down and place your hands under
Remain flat until the heat and two shock waves have passed.
If You Are Outside
When the Blast Occurs
Find something to cover your mouth and nose, such as a
scarf, handkerchief or other cloth.
Remove any dust from your clothes by brushing, shaking and
wiping in a ventilated area - however, cover your mouth and nose while you do
Move to a shelter, basement or other underground area,
preferably located away from the direction that the wind is blowing.
Remove clothing since it may be contaminated. If possible,
take a shower, wash your hair and change clothes before you enter the shelter.
If You Are Already in
a Shelter or Basement
Cover your mouth and nose with a face mask or other
material (such as a scarf or handkerchief) until the fallout cloud has passed.
Shut off ventilation systems and seal doors or windows
until the fallout cloud has passed. After the fallout cloud has passed, unseal
the doors and windows to allow for some air circulation.
Stay inside until authorities say it is safe to come out.
Listen to the local radio or television for information and
advice. Authorities may direct you to stay in your shelter or evacuate to a
safer place away from the area.
If you must go out, cover your mouth and nose with a damp
Use stored food and drinking water. Do not eat local fresh
food or drink water from open water supplies.
Clean and cover any open wounds on your body.
If You Are Advised to
Listen to the radio or television for information about
evacuation routes, temporary shelters and procedures to follow.
Before you leave, close and lock windows and doors and turn
off air conditioning, vents, fans and furnace. Close fireplace and dampers.
Take disaster supplies with you (such as a flashlight and
extra batteries, battery-operated radio, first aid kit and manual, emergency
food and water, non-electric can opener, essential medicines, cash, credit cards
and sturdy shoes).
Remember your neighbors may require special assistance,
especially infants, elderly people and people with disabilities.
Is a Nuclear Bomb the
Same as a Suitcase Bomb?
The “suitcase” bombs that have been described in
news stories in recent years are small nuclear bombs. A suitcase bomb would
produce a nuclear blast that is very destructive, but not as great as a nuclear
weapon developed for military purposes.
Is a Nuclear Bomb the
Same as a Dirty Bomb?
A nuclear blast is different than a dirty
bomb. A dirty bomb, or radiological dispersion device, is a bomb that uses
conventional explosives such as dynamite to spread radioactive materials in the
form of powder or pellets. It does not involve the splitting of atoms to produce
the tremendous force and destruction of a nuclear blast, but rather spreads
smaller amounts of radioactive material into the surrounding area. The main
purpose of a dirty bomb is to frighten people and contaminate buildings or land
with radioactive material.
Would an Airplane Crash
into a Nuclear Power Plant Have the Same Effect as a Nuclear Blast?
While a serious event such as a plane crash into a
nuclear power plant could result in the release of radioactive material into the
air, a nuclear power plant would not explode like a nuclear weapon. There may be
a radiation danger in the surrounding areas, depending on the type of the
incident, the amount of radiation released and the current weather patterns.
Radiation would be monitored to determine the potential danger, and people in
the local area would be evacuated or advised on how to protect themselves.
Do I Need to Take
Potassium Iodide (KI) If There is a Nuclear Blast?
Local emergency management officials will tell
people when to take KI. If a nuclear incident occurs, officials will have to
find out which radioactive substances are present before recommending that
people take KI. If radioactive iodine is not present, then taking KI will not
protect people. If radioactive iodine is present, then taking KI will help
protect a person’s thyroid gland from the radioactive iodine. Taking KI will not
protect people from other radioactive substances that may be present along with
the radioactive iodine.