Sheltering In Place: Nuclear & Radiological Events

Preparation Steps

• Identify the best shelter room in your building: a basement or an interior room with no or few windows provides the most protection; concrete and brick construction provides significantly more shielding than wood.
• Pre-position at least 3 days of water (1 gallon/person/day), sealed non-perishable food, medications, a battery-powered radio, and a flashlight in your designated shelter room.
• Store duct tape and plastic sheeting to seal gaps around doors and windows rapidly.
• Know how to shut off your HVAC system at the main control so you can stop outside air from entering.
• Discuss the plan with all household members so everyone can act without confusion during an emergency.

Immediate Actions

• Go inside a solid building immediately — the more mass (concrete, brick, earth) between you and the outside, the better.
• Move to the innermost room or the basement, staying as far from exterior walls and windows as possible.
• Close and lock all windows and doors.
• Turn off all fans, air conditioning, and HVAC systems — these draw outside air that may carry radioactive particles.
• Seal visible gaps under doors and around windows with damp towels, duct tape, and plastic sheeting.
• Tune to an emergency broadcast station for official instructions; stay sheltered for at least 24 hours unless told to evacuate — radioactive fallout levels drop by roughly 90% in the first 7 hours and continue to drop sharply.

What to Avoid

• Do not go outside during the first 24 hours after a nuclear detonation — this is the peak fallout period and outdoor exposure is most dangerous.
• Do not assume outside is safe because you cannot see or smell anything — radiation is completely invisible and odorless.
• Do not open windows for fresh air under any circumstances until the official all-clear is issued.
• Avoid excessive mobile phone use — preserve your battery for receiving emergency alerts.
• Do not drink tap water or eat food that was outside and exposed until authorities confirm it is uncontaminated.

Supplies Needed

• 3-day supply of water (at least 1 gallon per person per day) in sealed containers.
• Sealed non-perishable food for 3 days.
• Battery-powered or hand-crank emergency radio.
• Prescription medications for all household members.
• KI (potassium iodide) tablets if pre-distributed by local authorities.
• Duct tape and plastic sheeting for sealing the shelter room.

Recovery Steps

• Wait for an official all-clear from emergency authorities before leaving your shelter — do not exit based on assumptions.
• Before leaving the shelter, remove your outer clothing and seal it in a bag; shower with soap and water.
• Discard any food, water, or beverages that were stored outside or in an unsealed container during the event.
• Seek medical evaluation, especially if you were exposed before reaching shelter.
• Follow all further official instructions regarding safe zones, water safety, and decontamination procedures.