How long do I need to stay inside during a radiation emergency?

At least 24 hours, unless there is an immediate danger like fire or structural damage, or officials tell you it is safe to leave sooner. Radiation levels decrease rapidly and become significantly less dangerous during the first 24 hours.

How much time would I have to find shelter after a nuclear detonation?

If you have warning, you typically have 10 minutes or more before fallout begins arriving in areas outside the immediate blast zone. That is enough time to reach a sturdy building, ideally one with a basement or a center room away from windows.

What should I do to decontaminate after possible exposure?

Once inside, remove your outer layer of clothing, which removes a large share of surface contamination, and place it away from people and pets. Shower or wash exposed skin and hair with soap and water. If you cannot shower, wipe uncovered skin and hair with a clean, wet cloth.

Is it normal to feel distressed after a radiation emergency?

Yes. CDC guidance specifically notes that radiation emergencies can be stressful, and encourages talking with someone you trust or a counselor if you are feeling upset. Monitoring your own wellbeing after the event matters as much as the physical safety steps.

Radiation Emergency Checklist — Before, During & After

Phase 1

Before a radiation emergency. Three steps cover nearly all of it.

Get inside, stay inside, stay tuned applies whether the source is a nuclear power plant accident, a transportation incident, or a detonation. Knowing your shelter location ahead of time is what makes those three steps fast when it matters.

Shelter Safety

Know the get inside, stay inside, stay tuned steps. The basement or center of a sturdy building, away from windows, offers the best protection for the first 24 hours

Home Protection

Precut plastic sheeting and tape for doors, windows, and vents, so you can seal an interior room quickly

Water

Store 1 gallon per person per day for at least 3 days, including pets

Food

Build a 3-day supply of shelf-stable food per person that needs no cooking

Power and Lighting

Get LED lanterns or flashlights for every main room
Get a power bank for each phone in your household
Keep spare batteries stocked and grouped by size

Medical

Get a complete first aid kit and check expiration dates yearly
If you take daily medication, ask your doctor or pharmacist about an early refill to build a 7-day buffer

Communications

Turn on Wireless Emergency Alerts on every phone in your household
Get a battery-powered or hand-crank NOAA weather radio, one of the best ways to stay tuned

Documents

Get a waterproof, fireproof container for document copies, plus offline digital backups

Evacuation

Pack a 72-hour bag for each person in your household: medication, a change of clothes, document copies, water, and a phone charger
Identify your household meeting point and one out-of-area contact

Phase 2

During a radiation emergency. Get inside. Stay inside. Stay tuned.

Putting walls and distance between yourself and the outside is the single most protective action available. Everything else is about waiting it out and getting good information.

Get Inside

If you see a bright flash, take cover immediately behind anything solid. If you're outside with no shelter, lie face down to protect exposed skin
Move to the nearest sturdy building as quickly as possible. You typically have 10 minutes or more before fallout arrives
Choose the basement or center of the building, away from windows, putting as many walls as you can between you and the outside
If you're driving, stop and go inside the nearest sturdy building rather than trying to outrun the fallout

Stay Inside, Stay Tuned

Stay in your shelter location for at least 24 hours unless there's an immediate danger, or officials say it's safe to leave
Turn off fans, air conditioning, and forced-air heating that draws in outside air. Close windows, doors, and fireplace dampers
Keep pets inside with you
Listen to your NOAA weather radio, TV, or phone for updates, and follow instructions on when and how to evacuate

Phase 3

After a radiation emergency. Clean up, then wait for the all-clear.

Removing surface contamination is straightforward and effective. After that, patience and good information matter more than any single action.

Decontamination

Once inside, remove your outer layer of clothing and place it in a sealed bag away from people and pets
Shower or wash exposed skin and hair with soap and water. If you can't shower, wipe uncovered skin with a clean, wet cloth
Gently clean any pets that were outside after fallout arrived

Recovery

Don't leave your shelter until local officials say it's safe, unless you have a life-threatening condition
If you evacuated, don't return home until officials confirm it's safe
A radiation emergency can be stressful. Talking with someone you trust, or a counselor if you'd find that helpful, is a reasonable next step

Gear

Still need to get equipped? Start here.

A shelter kit, a radio, and a few days of supplies do most of the work here. These are the items worth having ready.

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Radiation Emergency Checklist. Before, during, and after.