Radiological Dispersion Device
Radiological Dispersion Device (RDD) combines a conventional explosive device — such
as a bomb — with radioactive material. It is designed to scatter dangerous and
sub-lethal amounts of radioactive material over a general area.
RDDs appeal to terrorists because they require limited technical knowledge to
build and deploy compared to a nuclear device. The size of the affected area
and the level of destruction caused by an RDD would depend on the
sophistication and size of the conventional bomb and other factors. The area
affected could be placed off-limits to the public for several months during
Before a Radiological Dispersion Device Event
There is no way of knowing how much warning time there will
be before an attack by terrorists using a Radiological Dispersion Device (RDD),
so being prepared in advance and knowing what to do and when is important. To
prepare for an RDD event, you should do the following:
The following describes
the two kinds of shelters:
- Build an Emergency
Supply Kit with the addition of duct tape and scissors.
- Make a Family
- 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, such as basements, subways, tunnels, or the windowless center area
of middle floors in high-rise buildings.
- 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.
- Taking shelter during an RDD event is absolutely necessary.
There are two kinds of shelters - blast and fallout.
- 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 an Radiological Dispersion Device Event
While the explosive blast will be immediately obvious, the
presence of radiation will not be known until trained personnel with
specialized equipment are on the scene. If the explosion or radiological release occurs inside, get
out immediately and seek safe shelter. Otherwise, if you are:
- Seek shelter indoors immediately in the nearest undamaged
- If appropriate shelter is not available, cover your nose and
mouth and move as rapidly as is safe upwind, away from the location of the
explosive blast. Then, seek appropriate shelter as soon as possible.
- Listen for official instructions and follow directions.
- If you have time, turn off ventilation and heating systems,
close windows, vents, fireplace dampers, exhaust fans, and clothes dryer vents.
- Retrieve your disaster supplies kit and a battery-powered
radio and take them to your shelter room.
- Seek shelter immediately, preferably underground or in an
interior room of a building, placing as much distance and dense shielding as
possible between you and the outdoors where the radioactive material may be.
- Seal windows and external doors that do not fit snugly with
duct tape to reduce infiltration of radioactive particles. Plastic sheeting
will not provide shielding from radioactivity nor from blast effects of a
- Listen for official instructions and follow
After an Radiological Dispersion Device Event
After finding safe shelter, those who may have been exposed
to radioactive material should decontaminate themselves. To do this, remove and
bag your clothing (and isolate the bag away from you and others), and shower
thoroughly with soap and water. Seek medical attention after officials indicate
it is safe to leave shelter.
Contamination from an RDD event could affect a wide area,
depending on the amount of conventional explosives used, the quantity and type
of radioactive material released, and meteorological conditions.
Follow these additional guidelines after an RDD event:
- Continue listening to your radio or watch the television for
instructions from local officials, whether you have evacuated or
- Do not return to or visit an RDD incident location for any
Description of Radiation Hazard Scale Categories
Category 5 means that radiation doses are dangerously high and
High doses of radiation
can cause massive damage to organs of the body and kill the person. The exposed
person loses white blood cells and the ability to fight infections. Diarrhea
and vomiting are likely. Medical treatment can help, but the condition may
still be fatal in spite of treatment. At extremely high doses of radiation, the
person may lose consciousness and die within hours.
Category 4 means that radiation doses are dangerously high and can
make people seriously ill. Radiation doses are not high enough to cause death,
but one or more symptoms of radiation sickness may appear.
Radiation sickness, also known
as Acute Radiation Syndrome (ARS), is caused by a high dose of radiation. The
severity of illness depends on the amount (or dose) of radiation. The earliest
symptoms may include nausea, fatigue, vomiting, and diarrhea. Symptoms such as
hair loss or skin burns may appear in weeks.
Category 3 means that radiation doses are becoming high enough
where we may expect increased risk of cancer in the years ahead for people who
Leukemia and thyroid cancers can appear in as few as 5 years after
exposure. Other types of cancer can take decades to develop. Studies have shown
that radiation exposure can increase the risk of people developing cancer. This
increased risk of cancer is typically a fraction of one percent. The lifetime
risk of cancer for the population due to natural causes is approximately 40%.
The increase in risk of cancer from radiation depends on the amount (or dose)
of radiation, and it becomes vanishingly small and near zero at low doses of
Category 2 means that radiation levels in the environment are
higher than the natural background radiation for that geographic area. However,
these radiation levels are still too low to observe any health effects.
When radiation levels are
higher than what we normally have in our natural environment, it does not
necessarily mean that it will cause us harm.
Category 1 means that radiation levels in the environment are
within the range of natural background radiation for that geographic area.
Low amounts of radioactive
materials exist naturally in our environment, food, air, water, and
consequently in our bodies. We are also exposed to radiation from space that
reaches the surface of the Earth.These conditions are natural, and this
radiation is called the natural background radiation.