Disaster Supplies Kit
Thunderstorms and lightning
Winter storms and extreme cold
Landslides and debris flow
Hazardous materials incidents
Household chemical emergencies
Nuclear power plant emergencies
Radiological dispersion device events
Recovering from Disaster
Health and safety guidelines
Seeking disaster assistance
Coping with disaster
Radiological Dispersion Device
Terrorist use of an RDD—often called “dirty nuke” or “dirty
bomb”—is considered far more likely than use of a nuclear
explosive device. An RDD combines a conventional explosive
device with radioactive material. It is designed to scatter
dangerous and sub-lethal amounts of radioactive material
over a general area.
The primary purpose of terrorist use of an RDD is to cause
psychological fear and economic disruption. Some devices
could cause fatalities from exposure to radioactive
materials. Depending on the speed at which the area of the
RDD detonation was evacuated or how successful people were
at sheltering-in-place, the number of deaths and injuries
from an RDD might not be substantially greater than from a
conventional bomb explosion.
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, the type of radioactive material
used, the quality and quantity of the radioactive material
and the local meteorological conditions—primarily wind and
precipitation. The area affected could be placed off-limits
to the public for several months during cleanup efforts.
Take Protective Measures
What can I do before a RDD Event occurs?
There is no way of knowing how much warning time there will
be before an attack by terrorists using an RDD, so being
prepared in advance and knowing what to do and when is
important. Take the same protective measures you would for
fallout resulting from a nuclear blast.
What do I do During a RDD 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.
Whether you are indoors or outdoors, home or at work, be
extra cautious. It would be safer to assume radiological
contamination has occurred—particularly in an urban setting
or near other likely terrorist targets—and take the proper
precautions. As with any radiation, you want to avoid or
limit exposure. This is particularly true of inhaling
radioactive dust that results from the explosion. As you
seek shelter from any location (indoors or outdoors) and
there is visual dust or other contaminants in the air, try
to avoid the area as breathing and proximity to it could
If the explosion or radiological release occurs inside, get
out immediately and seek safe shelter. Otherwise, if you
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 or from blast effects of a nearby explosion.
Listen for official instructions and follow directions.
Seek shelter indoors immediately in the nearest undamaged
If appropriate shelter is not available, move as rapidly as
is safe upwind and away from the location of the explosive
Then, seek appropriate shelter as soon as possible.
Listen for official instructions and follow directions.
What do I do After a RDD 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, isolate the bag away
from other inhabitants and shower thoroughly with soap and
water. Seek medical attention after officials indicate it is
safe to leave shelter.
Contamination from a 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. Thus, radiation dissipation rates
vary, but radiation from an RDD will likely take longer to
dissipate due to a potentially larger localized
concentration of radioactive material.
Follow these additional guidelines after a RDD event:
Continue listening to your radio or watch the television for
instructions from local officials, whether you have
evacuated or sheltered-in-place
Do not return to or visit an RDD incident location for any
Follow the instructions for recovering from a disaster in
Homeland Security Advisory System
The Homeland Security Advisory System was designed to
provide a national framework and comprehensive means to
broadcast information regarding the risk of terrorist acts
to the following:
Federal, state, and local authorities
The private sector
The American people
This system provides warnings in the form of a set of
graduated threat conditions that increase as the risk of the
threat increases. Risk includes both the probability of an
attack occurring and its potential gravity. Threat
conditions may be assigned for the entire nation, or they
may be set for a particular geographic area or industrial
sector. At each threat condition, government entities and
the private sector, including businesses and schools, would
implement a corresponding set of protective measures to
further reduce vulnerability or increase response capability
during a period of heightened alert.
There are five threat conditions, each identified by a
description and corresponding color. Assigned threat
conditions will be reviewed at regular intervals to
determine whether adjustments are warranted.
Threat Conditions and Associated Protective Measures
There is always a risk of a terrorist threat. Each threat
condition assigns a level of alert appropriate to the
increasing risk of terrorist attacks. Each threat condition
contains suggested protective measures that the government,
the private sector and the public can take.
In each case, as threat conditions escalate, protective
measures are cumulative to those already taken in lower
Citizen Guidance on the Homeland Security Advisory System
Develop a family emergency plan
Create an Emergency Supply Kit for your household
Know where to shelter and how to turn off utilities (power,
gas, and water) to your home
Examine volunteer opportunities in your community and donate
Consider completing an American Red Cross first aid, CPR
course or Community Emergency Response Team (CERT) course.
Complete recommended steps at level green
Review stored disaster supplies and replace items that are
Be alert to suspicious activity and report it to proper
Complete recommended steps at levels green and blue
Ensure disaster supplies are stocked and ready
Check telephone numbers in family emergency plan and update
Develop alternate routes to/from work or school and practice
Continue to be alert for suspicious activity and report it
Complete recommended steps at green, blue and yellow levels
Exercise caution when traveling
Pay attention to travel advisories
Review your family emergency plan and make sure all family
members know what to do
Check on neighbors or others that might need assistance in
Complete all recommended actions at green, blue, yellow and
Listen to local emergency management officials
Stay tuned to TV or radio for current information
Be prepared to shelter or evacuate, as instructed
Expect traffic delays, restrictions and searches
Provide volunteer services only as requested
Contact your school and business to determine status of work
*Developed with input from the American Red Cross.
To determine the current threat level visit Homeland
Security. Keep your family informed when changes in the
threat level occur and go over the personal actions you need