There is no magic formula that guarantees protection from acts of terrorism, but there are steps anyone can take to reduce the risks. The following basic guide is based on interviews with experts.

In General

• Do what you're told. If there is an announcement over TV or radio, or if a firefighter, police officer or other official tells you to do something, just do it. A crisis is no time to second-guess the one group of people with the expertise and equipment to know what's actually going on. Their specific instructions should take precedence over general guides such as this one.

If you're warned of an explosion

• Duck and cover. Get away from windows and behind something solid. Then curl up to protect your face and eyes.

If you're outside and you hear an explosion, or if you see people choking or collapsing

• Cover your nose and mouth. The big danger with most toxic substances is inhaling them. Even thin fabrics-a handkerchief, scarf, or shirt-will reduce your chance of inhaling radioactive particles, many chemical and biological agents, and the choking dust that ordinary bombs produce.
• Move away at an angle. If you're downwind of the attack, something dangerous may be drifting toward you. Since you can't outrun the wind, the way to get out of its path is to go sideways to the direction that it's blowing. Going around a corner will also put a building between you and the source of danger.
• Get inside. Find an intact, sturdy building and go in it. Modern buildings are fairly airtight and will keep out most toxic substances for some time.
• Strip and shower. If you actually were exposed to something toxic, most of it will have settled on your outer layer of clothing. Carefully take your outer garments off (ideally, shower with your clothes on first so they are safer to handle) and put them where no one will touch them (ideally, sealed in a plastic bag). Then shower or have someone hose you down, thoroughly but gently, to get the residue off your skin.

EXCEPTION: A few toxic chemicals react dangerously with water; if anything strange happens, stop showering immediately.

If you're inside and the problem is outside

• Close up. Closing doors and windows-and turning off air conditioners or heaters -will make most modern buildings reasonably airtight. That will keep most toxic substances from drifting in. If the windows are broken (say, by an explosion) or your part of the building is otherwise leaky, find an intact room to shelter in.
• Move away from windows. Just in case there is a second explosion, or a release of highly penetrating (gamma) radiation, you want to be behind a nice, solid wall.
• Stay put and watch TV or listen to the radio. Keep an eye out for official announcements over television and radio. Unless there is something obviously wrong with the building you are in (e.g., it is right next to where a toxic cloud is being released, or the windows are blown out, or it is burning down), it's probably safer to stay put than to go outside. Wait for someone in authority to tell you when, how, and where to evacuate.

If you're inside and the problem is inside

• Get out. Because modern buildings are fairly airtight, a dangerous substance released inside one will stay dangerously concentrated. If people inside your building are choking and collapsing, or if the building is on fire, it's time to head for another, safer shelter.