to Shelter-in-Place (Chemical
applies to several types of terrorist attacks, but details will vary.
For example, you would use duct tape and plastic sheeting to seal an
internal room against chemical agents. For sheltering against radiation
dispersed by a radiological dispersion device (RDD or “dirty
bomb”) or radioactive fallout particles after a nuclear
explosion, you would normally prefer a basement shelter to a higher
floor; duct tape and plastic would help keep radioactive dust out, but
primary protection from radioactive particles would be achieved by
applying the principles of mass, distance, and time. (See Factors
for Protection From Radioactive Fallout.)
If officials advise people in a specific area to shelter-in-place
because of a short-term chemical release,
households should have the following in the shelter-in-place room:
sheeting pre-cut to fit room openings. (Cut the plastic a minimum of 6
inches wider than each opening. The thickness of the plastic should be
4 to 6 mils or greater.)
tape and scissors. (The thickness of the duct tape should be 10
mils or greater.)
A shelter-in-place room should be an interior room, preferably one
without windows, that you can seal to block out air that may be
contaminated by the short-term release of hazardous chemical agents.
The room should be above the ground-level floor. In the case of a
chemical threat, an above-ground location is preferable because some
agents are heavier than air and may seep into basements even if the
windows are closed. Guidelines for sheltering-in-place are based on the
need to shelter for only a few hours— more than sufficient
time for a short-term release of airborne agents to dissipate. Ten
square feet of floor space per person will provide sufficient air to
prevent carbon dioxide build-up for up to five hours, assuming each
person is resting and breathing at a normal rate.
a Chemical Attack
following are guidelines for what you should do in a chemical attack.
you are instructed to remain in your home or office building, you
and lock all windows and exterior doors.
off all ventilation, including furnaces, air conditioners, vents, and
to shelter in an internal room and take your Disaster Supplies Kit. Be
sure you have a working battery-powered radio.
the room with duct tape and plastic sheeting. Use duct tape with a
minimum thickness of 10 mils and pre-cut plastic sheeting with a
thickness of 4 to 6 mils or greater to seal all cracks around doors,
windows, and vents, and all wall plugs, switch plates, and cables.
you are told there is danger of explosion, close the window shades,
blinds, or curtains.
your emergency contact. Ideally your room will have a hard-wired
telephone. Cellular telephone service may be overwhelmed or damaged
during an emergency. You will need a working phone if you have to
report a life-threatening emergency.
listening to your radio or television until you are told all is safe or
you are told to evacuate. Local officials may call for evacuation in
specific areas at greatest risk in your community.
the fireplace damper.
your pets with you, and be sure to bring additional food and water for
you are caught in an unprotected area, you should:
upwind of the contaminated area.
shelter as quickly as possible.
filters may be useful in biological
you have a central heating and cooling system in your home with a HEPA
filter, leave it on if it is running or turn the fan on if it is not
running. Moving the air in the home through the filter will help remove
the agents from the air.
If you have a portable HEPA filter, take it with you to the internal
room where you are taking shelter and turn it on. If you are in an
apartment or office building that has a modern central heating and
cooling system, the system’s filtration should provide a
relatively safe level of protection from outside biological
HEPA filters will not filter chemical agents.