Because
of recent terrorist events, people have expressed concern about the possibility
of a terrorist attack involving radioactive materials, possibly through
the use of a “dirty bomb,” and the harmful effects of radiation from such
an event. The Centers for Disease Control and Prevention has prepared this
fact sheet to help people understand what a dirty bomb is and how it may
affect their health.
What
a “dirty bomb” is
A dirty bomb, or radiological dispersion device, is a bomb that combines conventional
explosives, such as dynamite, with radioactive materials in the form of powder
or pellets. The idea behind a dirty bomb is to blast radioactive material into
the area around the explosion. This could possibly cause buildings and people
to be exposed to radioactive material. The main purpose of a dirty bomb is
to frighten people and make buildings or land unusable for a long period of
time.
Dirty
bomb versus atomic bombs in Hiroshima and Nagasaki
The atomic explosions that occurred in Hiroshima
and Nagasaki were conventional nuclear weapons involving a fission
reaction. A dirty bomb is designed to spread radioactive material
and contaminate a small area. It does not include the fission products
necessary to create a large blast like those seen in Hiroshima
and Nagasaki.
Sources
of the radioactive material
There has been a lot of speculation about where
terrorists could get radioactive material to place in a dirty bomb.
The most harmful radioactive materials are found in nuclear power
plants and nuclear weapons sites. However, increased security at
these facilities makes obtaining materials from them more difficult.
Because of the dangerous and difficult aspects of obtaining high-level radioactive
materials from a nuclear facility, there is a greater chance that the radioactive
materials used in a dirty bomb would come from low-level radioactive sources.
Low-level radioactive sources are found in hospitals, on construction sites,
and at food irradiation plants. The sources in these areas are used to diagnose
and treat illnesses, sterilize equipment, inspect welding seams, and irradiate
food to kill harmful microbes.
Dangers
of a dirty bomb
If low-level radioactive sources were to be
used, the primary danger from a dirty bomb would be the blast itself.
Gauging how much radiation might be present is difficult when the
source of the radiation is unknown. However, at the levels
created by most probable sources, not enough radiation would be
present in a dirty bomb to cause severe illness from exposure to
radiation.
Past
use of dirty bombs
According to a United Nations report, Iraq tested
a dirty bomb device in 1987 but found that the radiation levels
were too low to cause significant damage. Thus, Iraq abandoned
any further use of the device.
What
people should do following an explosion
Radiation cannot be seen, smelled, felt, or tasted by humans. Therefore, if
people are present at the scene of an explosion, they will not know whether
radioactive materials were involved at the time of the explosion. If people
are not too severely injured by the initial blast, they should:
- Leave
the immediate area on foot. Do not panic. Do not take public or private
transportation such as buses, subways, or cars because if radioactive
materials were involved, they may contaminate cars or the public transportation
system.
- Go
inside the nearest building. Staying inside will reduce people's exposure
to any radioactive material that may be on dust at the scene.
- Remove
their clothes as soon as possible, place them in a plastic bag, and seal
it. Removing clothing will remove most of the contamination caused by
external exposure to radioactive materials. Saving the contaminated
clothing would allow testing for exposure without invasive sampling.
- Take
a shower or wash themselves as best they can. Washing will reduce the
amount of radioactive contamination on the body and will effectively
reduce total exposure.
- Be
on the lookout for information. Once emergency personnel can assess the
scene and the damage, they will be able to tell people whether radiation
was involved.
Even if people
do not know whether radioactive materials were present, following these simple
steps can help reduce their injury from other chemicals that might have been
present in the blast.
Taking
potassium iodide (KI)
Potassium iodide, also called KI, only protects
a person's thyroid gland from exposure to radioactive iodine. KI
will not protect a person from other radioactive materials or protect
other parts of the body from exposure to radiation. It must be
taken prior to exposure (for example, if people hear that a radioactive
cloud is coming their way) or immediately after exposure to be
effective. Since there is no way to know at the time of an incident
whether radioactive iodine was used in the explosive device, taking
KI would probably not be beneficial.Also, KI can be dangerous to
some people. Taking KI is not recommended unless there is a risk
of exposure to radioactive iodine.
If
radioactive materials were involved
Keep televisions or radios tuned to local news networks. If a radioactive material
was released, people will be told where to report for radiation monitoring
and blood tests to determine whether they were exposed to the radiation as
well as what steps to take to protect their health.
Risk
of cancer from a dirty bomb
Some cancers can be caused by exposure to radiation. Being at the site where
a dirty bomb exploded does not guarantee that people were exposed to the radioactive
material. Until doctors are able to check people's skin with sensitive radiation
detection devices, it will not be clear whether they were exposed. Just because
people are near a radioactive source for a short time or get a small amount
of radioactive material on them does not mean that they will get cancer. Doctors
will be able to assess risks after the exposure level has been determined.
More information:
For more information
about medical response to detonation of a dirty bomb, see the following:
For
more information about radiation and emergency response, see the Centers
for Disease Control and Prevention's website at http://www.bt.cdc.gov or
contact the following organizations:
The
Centers for Disease Control and Prevention (CDC) protects people's
health and safety by preventing and controlling diseases and injuries;
enhances health decisions by providing credible information on critical
health issues; and promotes healthy living through strong partnerships
with local, national, and international organizations.
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