Before and After a Nuclear Incident

The advice below applies primarily to a nuclear detonation with fallout, a nuclear power plant accident, or a radiological release.

Before a Nuclear Incident

1. Have a Shelter Plan

The most effective protection against fallout is putting dense material between yourself and the radioactive particles outside.

Best shelters:

1. Basement of a sturdy concrete building
2. Underground shelter
3. Subway or underground parking structure
4. Interior room of a large concrete or brick building
5. Center of a multi-story building away from exterior walls

Avoid:

• Vehicles
• Mobile homes
• Tents
• Wooden sheds
• Buildings with large windows

Know in advance where you would go if authorities ordered immediate sheltering.

2. Maintain Emergency Supplies

Prepare enough supplies for at least 72 hours; one to two weeks is preferable.

Recommended supplies:

Water

Store:

• Minimum 4 liters (1 gallon) per person per day
• Ideally 14 days of water

Use sealed containers.

Food

Choose foods that:

• Require little or no cooking
• Have long shelf lives
• Are sealed against contamination

Examples:

• Canned foods
• Energy bars
• Dried foods
• Rice
• Pasta
• Peanut butter

Medical Supplies

Include:

• Prescription medications
• First-aid kit
• Spare glasses
• Basic pain relievers

Other Essentials

• Battery-powered radio
• Flashlights
• Spare batteries
• Power banks
• Hygiene supplies
• Blankets
• Important documents

3. Understand Potassium Iodide (KI)

Potassium iodide protects the thyroid from radioactive iodine.

Important points:

• It does not protect against most radioactive materials.
• It does not protect against external radiation.
• It should only be taken when recommended by public health authorities.

Having KI tablets available is reasonable in areas near nuclear facilities.

Common products include Potassium Iodide tablets.

4. Learn Local Emergency Information Sources

Know how authorities will communicate:

• Emergency alerts
• Radio broadcasts
• Government websites
• Mobile phone alerts

A battery-powered or hand-crank radio remains valuable if power and internet services fail.

5. Prepare Your Home

Consider:

• Plastic sheeting and tape for temporary sealing
• Spare air filters
• Fire extinguishers
• Backup power for communications

Know how to:

• Shut off ventilation systems if instructed
• Close windows and doors quickly

During a Nuclear Incident

1. Get Indoors Immediately

If you see a bright flash:

• Do not look directly at it.
• Drop to the ground.
• Cover exposed skin.
• Protect your eyes.

After the shock wave passes:

• Move immediately to the nearest substantial building.
• Do not attempt to watch events outdoors.

Every minute matters because fallout can begin arriving within minutes to hours.

2. Get to the Best Available Shelter

The priorities are:

1. Distance from fallout
2. Dense shielding
3. Time spent sheltered

Move to:

• Basement if available
• Center of building
• Lowest practical level

Stay away from:

• Windows
• Exterior walls
• Roofs

3. Stay Sheltered

A common rule of thumb:

• First 24 hours are critical.
• Fallout radiation decreases rapidly with time.

The "7-10 rule" is useful:

• After 7 hours, radiation falls to roughly 10% of the initial level.
• After 49 hours (7×7), roughly 1%.
• After 14 days, much lower still.

Do not leave shelter unless absolutely necessary or instructed by authorities.

4. Prevent Contamination

If you may have been outside during fallout:

Remove Outer Clothing

This alone can remove a large percentage of contamination.

Place clothing:

• In a sealed plastic bag
• Away from living areas

Shower

Use:

• Warm water
• Soap

Do not:

• Scrub aggressively
• Use hair conditioner (can bind particles to hair)

If no shower is available:

• Wipe exposed skin thoroughly

5. Protect Air, Food, and Water

Consume:

• Sealed food
• Bottled water

Avoid:

• Rainwater
• Open containers
• Fresh produce exposed outdoors
• Unprotected livestock products

Until authorities determine contamination levels.

After the Incident

1. Continue Following Official Instructions

Authorities may issue:

• Shelter-in-place orders
• Evacuation instructions
• Food restrictions
• Water advisories

Conditions can vary dramatically by location.

2. Monitor Radiation Information

Pay attention to:

• Radiation measurements
• Contamination maps
• Restricted zones

Some areas may remain safe while others require long-term controls.

3. Avoid Contaminated Areas

Stay away from:

• Dusty outdoor areas
• Debris fields
• Fallout hotspots

Radioactive particles can be inhaled or ingested long after the initial release.

4. Manage Food and Water Carefully

Only consume food and water that:

• Authorities have cleared
• Was sealed before contamination
• Comes from verified safe sources

Agricultural contamination can persist for weeks or months depending on the radionuclides involved.

5. Seek Medical Evaluation if Needed

Seek medical attention if you experience:

• Severe nausea and vomiting shortly after exposure
• Unusual fatigue
• Burns without obvious heat injury
• Unexplained bleeding
• Significant contamination concerns

Most people outside the immediate disaster zone are unlikely to receive radiation doses high enough to cause acute radiation sickness.

Key Priorities to Remember

In order of importance:

1. Get inside a substantial building.
2. Get to the deepest, most central location available.
3. Stay sheltered for at least 24 hours unless instructed otherwise.
4. Remove contaminated clothing and wash if exposed.
5. Use sealed food and water.
6. Follow official guidance before evacuating.
7. Take potassium iodide only when public health authorities recommend it.

For most nuclear incidents, effective sheltering during the first day provides the greatest reduction in radiation dose and is often more important than evacuation during the early fallout period.