Nuclear & Radiological FAQs
Find answers to the most common questions about nuclear safety, radiation exposure, understanding fallout, potassium iodide, and how to shelter in place if the unthinkable happens — because when it comes to nuclear threats, knowing what to do in advance could save your life.
Common Questions
How do I survive a nuclear attack?
Get inside a building with thick walls (concrete, brick) immediately, move to a basement or interior room, and stay put for at least 24 hours. Keep a NOAA radio and follow ready.gov/nuclear-explosion guidance. Distance from the blast, shielding by dense materials, and time indoors all reduce radiation exposure. Also applies to nuclear bomb or nuke scenarios.
How do I prepare for World War 3 (WW3)?
Build a 3-month emergency supply: water (1 gallon per person per day), food, first aid, medications, and communications. Establish sheltering plans for nuclear, biological, or chemical events. Keep essential documents in a go-bag. See FEMA guidance at ready.gov/nuclear-explosion for WW3-scale preparedness. WW3 preparation is the same as preparing for any nuclear or large-scale war event.
How do I prepare for war at home?
Maintain a 3-month supply of water, food, first aid, and medications. Establish sheltering plans and multiple evacuation routes. Review FEMA guidance at www.ready.gov/radiation on nuclear, biological, and chemical sheltering. Keep essential documents accessible in a go-bag. Home war preparation also covers how to survive in a war zone when evacuation is not possible.
What is potassium iodide used for?
Potassium iodide (KI) tablets saturate the thyroid with stable iodine so it cannot absorb radioactive iodine released by a nuclear event. KI only protects the thyroid; it does not protect against other radiation exposure. Take only when directed by public health officials.
What is fallout and how does it work?
Fallout is radioactive dust and debris that falls to the ground after a nuclear explosion. Larger particles fall within hours; finer particles can travel hundreds of miles. Exposure causes radiation sickness. Shelter indoors with HVAC off, seal windows, and follow 72-hour sheltering guidance. Review FEMA guidance at www.ready.gov/radiation
How far away from a nuclear blast is safe?
Distance and shielding both matter. Dense materials (concrete, brick, earth) provide protection; wood-frame houses provide little. For immediate effects, 5+ miles from ground zero of a small tactical weapon may survive with sheltering; large weapons require 20+ miles. Inside basements with heavy walls is safest. Review FEMA guidance at www.ready.gov/radiation.