For some natural or technological disasters, you may be directed by local officials to go to a community shelter for safety purposes. For others, you might be told to shelter-in-place, which is intended to keep you safe while remaining indoors.
To shelter-in-place means to select a small, interior room with no or few windows and taking refuge there. An above-ground location is preferable because some chemicals are heavier than air and may seep into basements even if the windows are closed. Large storage closets, utility rooms, pantries, or copy and conference rooms without exterior windows work well. Use duct tape and plastic sheeting (heavier than food wrap) to seal all cracks around the door and any vents into the room. There is no need to seal off your entire home or office with duct tape and plastic sheeting.
It is important to remember that instructions to shelter-in-place mean for you to shelter for a few hours, not days or weeks. There is little danger that the room in which you are taking shelter will run out of oxygen and you will suffocate in less than a day. Keep listening to your radio or television until you are told all is safe.