In the event of a chemical or biological incident or attack, it may become necessary to take refuge in a sealed room if evacuation is not practical. If the room has ten square feet of floor space per person, it should provide enough air for up to five hours.
In order to successfully seal a room the following measures should be taken:
- Select a room or an upstairs floor with the least number of windows and doors.
- Choose a large room with access to a bathroom and a telephone.
- Close and lock all windows and doors.
- Seal all cracks around the window and door frames with wide tape.
- Cover the windows and exterior doors with plastic sheets and seal with pressure-sensitive adhesive tape.
- Seal all openings in windows and doors (cracks, keyholes, gaps under doorways) with cotton wool or wet rags and duct tape.
- Shut down all window and central air units.
- Shut down all heaters and water heaters since they can draw in outside air and can create carbon monoxide if deprived of air. (Note: This can cause loss of life if not performed.)
The room should also be stocked with bottled water, food, medicine, emergency light, radios, batteries, a fire extinguisher and other essentials. Do not leave the room until you get instructions from the Emergency Broadcast System to do so.
During Gulf War II, the Israeli Ministry of Civil Defense called on all citizens to transform one room into a sealed room.
Since its creation, the Department of Homeland Security has also released guidelines regarding instructions on sealing rooms in case of a terrorist attack.