How do you decontaminate yourself after radioactive fallout?

Short answer. Get inside a building first. Then carefully take off your outer layer of clothing, which can remove up to 90% of radioactive material, and seal it in a plastic bag away from people and pets ¹. Shower with warm water, soap and shampoo, without conditioner, which can make radioactive material stick to hair ²⁶. Do not scrub your skin. Stay inside and follow official instructions ³.

What is the first thing to do if fallout may be coming down?

Get inside, stay inside and stay tuned. That is the core message of U.S. agencies ³⁴. The CDC advises getting inside a building right away. It notes that cars do not provide good protection from radioactive material ³. Because radioactive materials become weaker over time, the CDC says that staying inside for at least 24 hours can protect you and your family until it is safe to leave the area ³. Do not go back outside to collect relatives: the CDC warns that this could expose both you and them to dangerous levels of radiation ³.

Canada gives the same order: go inside the nearest building, at its centre or in its basement, away from doors and windows, and do not leave until local authorities tell you to ⁸. The UK Health Security Agency (UKHSA) calls going inside and staying inside with doors and windows closed "the most important thing you can do", and tells people to tune in to news updates ⁶.

Decontamination comes once you are inside. The CDC says it lowers your exposure to harmful radioactive material and should start as soon as possible ¹³.

How do you remove contaminated clothing safely?

Clothing is the main barrier between fallout dust and your skin. That is why taking it off is the biggest single step.

• Take off the outer layer. The CDC ¹, UKHSA ⁶ and Ready.gov ⁴ all state that removing the outer layer of clothing can remove up to 90% of radioactive material. UKHSA and the German BfS add your shoes ⁶⁷.
• Do not shake anything. Shaking can release radioactive dust that you could breathe in ¹⁴.
• Avoid pulling clothes over your head. UKHSA advises cutting clothing off where necessary, and avoiding touching the outside of the clothes with your skin ⁶. If a clean face mask or face covering is at hand, put it on first ⁶.
• Bag it. Put clothing in a plastic bag or other sealable container and store it far away from people and pets ¹. Germany's Federal Office for Radiation Protection (BfS) advises storing the sealed bag outside the dwelling ⁷.
• Do not put contaminated clothes back on. Put on clean clothes that were stored indoors ⁶.

"Up to 90%" is a maximum, not a guarantee. How much comes off depends on how much was deposited and where. Washing removes much of what remains on uncovered skin and hair.

How should you shower after radiation exposure?

The CDC ¹² and UKHSA ⁶ give nearly identical instructions:

1. Take a warm shower and wash gently with plenty of soap ¹. UKHSA also specifies warm water ⁶.
2. Wash your hair with shampoo or soap ¹. Do not use conditioner: the CDC says it will cause radioactive material to stick to your hair ², and UKHSA says it may fix contaminants to your hair ⁶. REMM, the U.S. medical reference, explains that conditioners can bind radioactive material to hair protein ⁵.
3. Do not scald, scrub or scratch your skin ¹.
4. Keep cuts and abrasions covered so radioactive material does not get into open wounds ¹.
5. Keep your mouth and eyes closed when washing your hair and face ⁶. The BfS adds that no water should get into the mouth, nose or eyes ⁷.

Tap water is fine. The CDC says that even if officials recommend bottled water for drinking, you can still use tap water for decontamination ¹. UKHSA says mains water from the shower or taps is safe to use ⁶.

What if you cannot shower?

Wash at a sink. Clean your hands, face and other uncovered parts with soap and plenty of water ¹. Without a sink, use a moist wipe, clean wet cloth or damp paper towel, paying special attention to hands and face ¹. Gently blow your nose and wipe your eyelids, eyelashes and ears ¹. UKHSA adds that you should wipe outwards, away from the nose and mouth ⁶.

Ready.gov notes two limits: household cleaning wipes should not be used on skin, and hand sanitizer does not protect against radioactive material ⁴.

Place used wipes, cloths and towels in a sealable bag, away from people and pets ¹.

How do you decontaminate pets?

The CDC says that if you are told to stay inside, pets should be inside too ³. Ready.gov advises cleaning any pet that was outside after the radioactive dust arrived. Brush its coat gently, then wash it with soap and water if available ⁴. The BfS recommends doing this in a separate room, away from the people sheltering, and wearing an FFP2 or FFP3 mask if one is available ⁷.

When helping another person or a pet, wear waterproof gloves and a face mask if possible. Keep cuts covered, bag the waste, then rewash your own hands, face and uncovered skin ²⁶.

What official agencies recommend

The core steps are the same everywhere: get inside, remove outer clothing, wash. The details differ.

Two differences matter in practice. First, Germany puts the undressing at the threshold and keeps the bag outside the home ⁷. The U.S. and UK steps start once you are inside ³⁶. Second, Canada's public page does not give a step-by-step method: it says to remove contaminated clothing and wash "if instructed to do so", and to follow officials' advice on how to decontaminate ⁸. In every country, instructions from local authorities during an actual event take priority over general guidance.

On water temperature, the CDC and UKHSA advise warm water for the public ¹⁶. REMM, written for medical teams, recommends tepid water and warns that cold water tends to close skin pores and trap contamination ⁵. REMM also cautions that vigorous decontamination can remove the skin's protective barrier ⁵. Both point the same way: comfortable water, gentle washing.

Frequently asked questions

Does removing clothes really remove 90% of the contamination?

The CDC, UKHSA and Ready.gov all say removing the outer layer can remove up to 90% of radioactive material ¹⁴⁶. REMM gives the same "up to 90%" figure for removal of all clothing in a medical setting ⁵. It is an upper figure. Washing exposed skin and hair is still needed afterwards.

Why should I not use hair conditioner?

Conditioner can bind radioactive material to the protein of the hair ⁵. The CDC says it will make radioactive material stick to your hair ², and UKHSA says it may fix contaminants there ⁶. Use shampoo or soap only.

Can I use tap water if the water supply may be contaminated?

Yes, for washing. The CDC says you can still use tap water for decontamination even if officials advise bottled water for drinking ¹. UKHSA says mains water is safe to use ⁶.

Is hand sanitizer enough?

No. Ready.gov states that hand sanitizer does not protect against radioactive material, and household cleaning wipes should not be used on skin ⁴. Use soap and water, or a moist wipe or wet cloth if no water is available ¹.

How long should I stay inside after decontaminating?

The CDC says staying inside for at least 24 hours can protect you until it is safe to leave ³. Canada says not to leave shelter until local authorities instruct you ⁸. Follow official broadcasts for your area.

Make it part of your plan

Decontamination works best when the steps are decided before an emergency: where to undress, where to keep the bags, which clothes stay indoors. The Phaenyx personal plan ($29 free for a limited time) brings the official guidance for your country together in one written household plan. Build your Phaenyx plan.

Sources

1. U.S. Centers for Disease Control and Prevention (CDC) — How to Self-Decontaminate after a Radiation Emergency — https://www.cdc.gov/radiation-emergencies/prevention/self-decontaminate.html (accessed 2026-10-20)
2. U.S. Centers for Disease Control and Prevention (CDC) — Decontamination for Yourself and Others — https://www.cdc.gov/radiation-emergencies/infographic/decontamination.html (accessed 2026-10-20)
3. U.S. Centers for Disease Control and Prevention (CDC) — Frequently Asked Questions about Radiation Emergencies — https://www.cdc.gov/radiation-emergencies/faq/index.html (accessed 2026-10-20)
4. Ready.gov (FEMA) — Radiation Emergencies — https://www.ready.gov/radiation (accessed 2026-10-20)
5. Radiation Emergency Medical Management (REMM), U.S. Department of Health and Human Services — Procedures for Radiation Decontamination — https://remm.hhs.gov/ext_contamination.htm (accessed 2026-10-20)
6. UK Health Security Agency (UKHSA) — Radiation self-decontamination guidance (2022) — https://assets.publishing.service.gov.uk/media/6565cb6e1524e6000da101c5/Radiation_self_decontamination_guidance__5_.pdf (accessed 2026-10-20)
7. Bundesamt für Strahlenschutz (BfS), Germany — Aufenthalt in Gebäuden — https://www.bfs.de/DE/themen/ion/notfallschutz/verhalten/aufenthalt-haus/aufenthalt-haus_node.html (accessed 2026-10-20)
8. Government of Canada — Radiological and nuclear emergencies – Get prepared — https://www.canada.ca/en/services/policing/emergencies/preparedness/get-prepared/hazards-emergencies/radiological/how-prepare.html (accessed 2026-10-20)