---
title: Nuclear accident and iodine tablets: what to do — InCaseMap
description: What to do after a nuclear accident in Lithuania: what the 3-minute siren means, how to shelter indoors, when and how many potassium iodide tablets to take by age, and where to get them.
url: https://incasemap.com/en/nuclear-accident-and-iodine-tablets
updated: 2026-10-16
language: en
publisher: InCaseMap
---

> Index of all pages on this site: https://incasemap.com/en/llms.txt — start there to find other pages.

# Nuclear accident and potassium iodide tablets: what to do

Guide · Radiation safety

The nuclear power plant closest to Lithuania is Astravets (Ostrovets) in Belarus. 17 municipalities, including Vilnius, lie within 100 km of it, and their residents are given potassium iodide tablets in advance.

Prepared by the [InCaseMap team](https://incasemap.com/en/about) · Updated 16 October 2026

>  **In short:** if you hear a 3-minute pulsing siren, the “Attention everyone” signal, turn on LRT radio or TV and follow the instructions. In a radiation emergency people are usually told to stay indoors: close windows and doors, switch off ventilation. Take potassium iodide tablets only when the Ministry of Health tells you to, never in advance: for an adult that is 2 tablets of 65 mg. Iodine tincture and supplements do not protect the thyroid.

## Radiation accident: what to do

### How you are warned

Warnings come through sirens (“Attention everyone”), the voice message “Radiation danger”, text messages, radio and television.

1. Go inside a building as quickly as possible and stay inside.
2. Close windows, doors, window vents and chimney dampers, cover ventilation openings. Plastic windows do not need extra sealing.
3. Switch off ventilation, air conditioning and warm-air heating.
4. A sealed basement is best. If there is none – stay in the middle of the building, away from the outer walls and the roof.
5. Bring animals inside; keep food and water in tightly closed containers.
6. Follow the messages on radio and television, prepare for a possible evacuation.
7. If you were outdoors – once inside, carefully take off your outer clothes, do not shake them, put them in a plastic bag, tie it, keep it away from you; wash under running water with soap for no less than 10 minutes.
8. Take potassium iodide tablets only when the Ministry of Health recommends it.

### Outdoors

Cover your nose and mouth with a cloth; do not touch objects or debris; go to the nearest building with undamaged windows and walls.

### Potassium iodide (65 mg tablet)

Adults and children from 12 years, pregnant and breastfeeding women – 2 tablets; 3–12 years – 1; from 1 month to 3 years – ½; newborns under 1 month – ¼. One dose protects for 24 hours. If your thyroid has been removed – not needed. The tablets protect only the thyroid.

### What not to do

- Do not take iodine solution, iodine sprays or dietary supplements with iodine – they do not protect, and alcoholic iodine solution is poisonous.
- Do not take potassium iodide without the Ministry of Health’s instruction.
- Do not go back home until officials say it is safe.

Based on: Radiation Protection Centre of Lithuania (RSC), Ministry of National Defence of Lithuania, Fire and Rescue Department of Lithuania (PAGD). Translated from the Lithuanian text that InCaseMap checked against the sources on 5 October 2026.

## How you will find out

Lithuania would learn about an accident abroad through international organisations and would warn residents with sirens, alerts on mobile phones, radio and TV. **A 3-minute pulsing siren** means “Attention everyone”: turn on LRT radio or TV as quickly as you can and listen for information. More on the signals — [sirens and air raid alerts](https://incasemap.com/en/sirens-and-air-raid-alerts).

The Radiation Protection Centre stresses three rules:

1. Spend as little time as possible in a contaminated area.
2. Try not to breathe in radioactive substances or take them in with food or water.
3. Stay as far as possible from the source of radiation or the contaminated area.

## What to do if you are told to stay indoors

1. Go inside — home or the nearest building you can seal.
2. Close windows, vents, doors, chimneys and ventilation ducts. Switch off ventilation, air conditioning and heating that draw in outside air.
3. Stay in the centre of the building or in the basement: radioactive substances settle on the outside of buildings, so it is safest as far as possible from outer walls and the roof.
4. If you were outdoors, take off your outer clothes by the door, put them in a bag and shower, or at least wash your face and hands.
5. Drink water and eat food that were in closed packaging or indoors. Don’t eat fruit and vegetables from your own garden until the authorities say it is safe.
6. If you must go out, cover your nose and mouth with a respirator or at least a cloth.
7. Listen to LRT and stay indoors until you are told you can go out or need to evacuate.

You can turn on the “Background radiation” layer on the InCaseMap map, but decisions on protective measures are made and announced by the authorities.

## Potassium iodide tablets: when and how many

The tablets protect only the thyroid and only against radioactive iodine. They do not stop other radioactive substances such as caesium or strontium — so staying indoors is still what matters most.

- **Take them only when the Ministry of Health recommends it** — on radio, TV or in a phone alert. Don’t take them in advance: this can harm your health.
- Best taken less than 24 hours before possible exposure or within 2 hours after it. Later they help less, and more than 8 hours after exposure they do little.
- Take them after a meal. For children, a tablet can be dissolved in water or liquid food and given straight away.
- One dose protects the thyroid for 24 hours.

| Age | Dose | 65 mg tablets |
| --- | --- | --- |
| Newborns under 1 month | 16 mg | ¼ |
| 1 month to 3 years | 32 mg | ½ |
| 3 to 12 years | 65 mg | 1 |
| Over 12 and adults | 130 mg | 2 |

Newborns, pregnant and breastfeeding women and people over 60 should take only one dose. For others, only the authorities may recommend a second dose, for example if the release goes on. Read the leaflet in the pack in advance, and if you have a thyroid condition, talk to your doctor.

- **Never drink iodine tincture**, not even diluted in water: it is for the skin only and is poisonous.
- Iodine solutions, sprays and supplements do not protect the thyroid — they contain too little stable iodine.
- Don’t give potassium iodide to animals: the State Food and Veterinary Service does not recommend it.

## Where to get the tablets

For residents of the 17 municipalities within 100 km of the Astravets plant, tablets are handed out through the municipalities and the pharmacies they name. Your municipality and the Ministry of Health announce the exact procedure. Keep the tablets where you can find them quickly, for example with your [72-hour kit](https://incasemap.com/en/72-hour-preparedness), and check the expiry date.

## Frequently asked questions

### Should I take iodine tablets in advance?

No. Potassium iodide tablets are taken only when radioactive iodine has spread and the Ministry of Health recommends it. Taking them in advance can harm your health.

### How many potassium iodide tablets should an adult take?

Two 65 mg tablets (130 mg) once, when the authorities recommend it. Children aged 3 to 12 take one tablet, from 1 month to 3 years half a tablet, newborns a quarter.

### Can iodine tincture replace potassium iodide tablets?

No. Iodine tincture is for the skin only and is poisonous; it must not be swallowed, even diluted. Iodine supplements do not protect the thyroid either.

### Is Vilnius within the Astravets nuclear plant zone?

Yes. Vilnius is within 100 km of the Astravets plant, the zone where thyroid blocking with potassium iodide may be needed after an accident. 17 municipalities are in this zone.

### Can radiation spread from person to person?

A person who was exposed to radiation but not contaminated does not emit radiation. Radioactive contamination on clothes and skin can spread by contact, so take off outer clothes and wash after being outdoors.

## Sources

- [Radiation Protection Centre — “What to do in a nuclear accident”, 2018](https://rsc.lrv.lt/uploads/rsc/documents/files/14_%20Plakatas%20Kaip%20elgtis%20branduolin%C4%97s%20avarijos%20atveju%202019-01-15%20(galut_).pdf) rsc.lrv.lt
- [Radiation Protection Centre — “Taking potassium iodide (KI) tablets after a nuclear accident”, 16 January 2025](https://rsc.lrv.lt/public/canonical/1737014693/517/KI%20lankstinukas_2025-01-16.pdf) rsc.lrv.lt
- [Ministry of National Defence — “What we need to know about preparing for emergencies and wartime: serious advice, light-hearted”, 2022](https://lt72.lt/wp-content/uploads/2022/07/Ka-turime-zinoti-rimti-patarimai-linksmai-2022-2.pdf) lt72.lt
- [PAGD, lt72.lt — “What to do in the event of a nuclear power plant accident”, 2024-05-16](https://lt72.lt/kaip-elgtis-jei-ivyktu-avarija-atomineje-elektrineje/) lt72.lt
- [What to know about taking potassium iodide tablets after a nuclear accident — Radiation Protection Centre (in Lithuanian)](https://rsc.lrv.lt/lt/dazniausiai-uzduodami-klausimai/gyventojams-1/branduoline-ar-radiologine-avarija/7-ka-reikia-zinoti-apie-kalio-jodido-tableciu-vartojima-ivykus-branduolinei-avarijai/) rsc.lrv.lt
- [What to do when you hear the 3-minute warning signal — Radiation Protection Centre (in Lithuanian)](https://rsc.lrv.lt/lt/dazniausiai-uzduodami-klausimai/gyventojams-1/branduoline-ar-radiologine-avarija/3-ka-daryti-isgirdus-3-minuciu-trukmes-ispejamaji-garsini-signala/) rsc.lrv.lt
- [Potassium iodide tablets and what to do in a radiation emergency — Vilnius City Municipality (in Lithuanian)](https://vilnius.lt/savivaldybe/saugus-miestas/civiline-sauga/informacija-apie-kalio-jodido-tabletes-ir-kaip-elgtis-radiacines-nelaimes-atveju) vilnius.lt
- [New potassium iodide tablets will be distributed to the public — Ministry of Health](https://sam.lrv.lt/en/during-the-visit-to-japan-the-focus-was-on-patient-safety/new-potassium-iodide-tablets-will-be-distributed-to-the-public) sam.lrv.lt
- [Belarusian nuclear power plant: frequently asked questions — Ministry of Health (in Lithuanian)](https://sam.lrv.lt/uploads/sam/documents/files/Veiklos_sritys/visuomenes-sveikatos-prieziura/Estremaliu%20situaciju%20valdymas/Da%C5%BEniausiai%20u%C5%BEduodami%20klausimai.pdf) sam.lrv.lt

This text summarises official guidance and does not replace instructions from the authorities. During an emergency, follow announcements from LRT and the authorities.

You may freely use this text and its data, commercially too — just add a link: `<a href="https://incasemap.com/en/nuclear-accident-and-iodine-tablets">InCaseMap</a>` ([more](https://incasemap.com/en/reuse-and-citation))

## Related

- [Sirens and air raid alerts](https://incasemap.com/en/sirens-and-air-raid-alerts): Heard sirens? Turn on LRT and follow official announcements. Air raid alert: go to the nearest shelter or an interior room away from windows. Step by step.
- [72-hour preparedness](https://incasemap.com/en/72-hour-preparedness): How to be self-sufficient for three days: water, food, medicines, a battery radio, cash, documents and a family plan. An emergency kit checklist.
- [Where to shelter at home](https://incasemap.com/en/where-to-shelter-at-home): Where to take cover if you can’t reach a shelter: the two-wall rule, the safest places in a flat and in a house, what to avoid and what a “Shelter” sticker really means.
- [Information without internet](https://incasemap.com/en/information-without-internet): Without internet, LRT radio still broadcasts official news and phone alerts arrive over the mobile network. What to prepare and how InCaseMap works offline.
- [Chemical accident](https://incasemap.com/en/what-to-do-chemical-accident): Chemical accident: turn on the radio, seal windows and doors, go up to the upper floors, do not hide in a basement. Based on PAGD and KAM.
- [Evacuation](https://incasemap.com/en/evacuation#ka-daryti-evakuacija): When an evacuation is announced: listen to the messages, take your documents, turn off water and gas, use only the designated roads. Based on the Ministry of National Defence and PAGD.
- [Air pollution and radiation](https://incasemap.com/en/air-pollution-map): Air pollution and background radiation