Radiation Emergency Checklist: The First Hour at Home

If you are told there has been a radiation emergency near you, the single most useful thing you can do in the first hour is get inside a building and stay there. Official advice is to go in, stay in and tune in: close doors and windows, keep away from external walls, and follow local radio, television or official online updates¹. You may need to stay indoors for one to two days².

Radiation is not like smoke or a chemical cloud. It cannot be seen, heard, smelt, tasted or felt, so everything will look normal outside even when something serious has happened². That is why the instruction to shelter matters more than your own senses, and why you should act on the warning rather than wait for evidence.

This checklist sets out what to do in order, what to have ready, how to strip contamination from clothes and skin, and when stable iodine tablets are, and are not, the right step. It is written for ordinary households, including those living near a nuclear site or naval base where these warnings are most likely.

The first-hour checklist

Work through this in order. The first three items are the ones that matter most, and they take minutes.

1. Get inside the nearest safe building. Go in as soon as you can, close doors and windows, and stay as far from external walls as possible³. Vehicles and tents do not provide sufficient shelter from significant radiation, so a car is not a substitute for a building¹.
2. Stay in. Do not go out to fetch children, shop or check on the street. You may need to stay indoors for one to two days².
3. Tune in. Use local radio, television or official sources online for public information and advice from the emergency responders². Keep listening for updates and wait for the all clear announcement before you change anything⁷.
4. Take off outer clothing if you may have been exposed. Simply taking off your outer clothing can remove around 90% of the contamination⁸. Put it in a plastic bag and tie it, and keep it away from people and pets until you are told what to do with it.
5. Wash if asked. You might be asked to decontaminate yourself, and the UK Health Security Agency publishes advice on how to remove radioactive material from skin and clothes safely².
6. Wait for instructions on iodine tablets. Do not take stable iodine unless you are told to. It is issued and timed for a reason, and a late dose can do more harm than good¹.
7. Check your emergency kit while you wait. A plan with contact numbers, a torch with spare batteries, a first aid kit, bottled water and ready-to-eat food are the basics⁹. Add any regular medicines and a note of the doses¹⁰.
8. Keep the phone for essentials. Rely on radio and official online updates for information rather than a stream of calls, and write down the contact details of anyone who might need checking on¹⁰.

Radiation looks normal: you will not see, smell or feel it

The hardest part of a radiation emergency for an ordinary household is that nothing looks wrong. Official guidance is blunt about it: with radiation everything will look normal and you will not see, smell or feel anything different³. Radiation cannot be seen, heard, smelt, tasted or felt, so it is important to follow the advice given to you, even if you cannot tell that anything has happened².

There are three ways radiation from a release can reach you: breathing in radioactive materials, direct exposure to material carried in the air or deposited on surfaces, clothing or skin, and eating or drinking contaminated food or water¹. Sheltering indoors addresses the first two, which is why it is the headline action. Food and water restrictions, where they are needed, come later and are announced officially.

This is also why you should not go outside to investigate, and why the advice to stay put applies even if the street looks entirely ordinary. If you are not involved in the incident but are close by or believe you may be in danger, the usual advice is go in, stay in, tune in⁵.

There is one important exception. There are always going to be particular occasions when you should not go in to a building, for example if there is a fire⁵. If your home is on fire or structurally unsafe, get away from it and follow the instructions being broadcast. The rule is to shelter from the radiation, not to shelter inside a danger.

Removing outer clothing takes off around 90% of contamination

If you were outside when a release happened, or you are not sure, the simplest decontamination step is also the most effective. Studies show that simply taking off your outer clothing can remove around 90% of the contamination¹. The UK Health Security Agency puts it as up to 90% of radioactive material removed by taking off the outer layer of clothing⁴.

Do it carefully:

• Take off outer layers first. Coat, jacket, shoes and outer garments come off before anything else⁴.
• Avoid pulling clothing over your head where you can, as this can spread material onto your face and hair⁸.
• Bag it and set it aside. Keep removed clothing away from children and pets until you are told how to dispose of it.
• Do not pull off clothing stuck to skin. If clothing is stuck, leave it and seek advice⁸.
• Wash with simple soap or a mild shampoo. Do not use conditioner when washing your hair, as this can bind contamination to hair¹.
• Do not smoke, eat or drink while you are contaminated or handling contaminated clothing⁸.

If you have a burn, remove clothing and jewellery near the burn unless it is melted or firmly stuck to the skin¹¹. Do not improvise treatment beyond basic first aid. For the fuller process, see Remove, Remove, Remove: What to Do After Contact With a Harmful Substance.

Stable iodine tablets: when to take them and how much

Stable iodine tablets are not a general radiation pill. They work on one specific hazard: radioactive iodine released from a faulty operating nuclear reactor, which can deliver a dose to the thyroid gland¹². Taking stable iodine at the right time blocks the absorption of radioactive iodine by the thyroid gland and speeds up the body's ability to remove it, but it does not protect against other sources of radiation¹.

Timing decides whether they help or harm:

A single dose provides protection for 24 hours¹. Doses differ by age, and the booklet issued with the tablets is the authority for your household:

Read the patient information leaflet before taking stable iodine tablets¹. Do not take them if you are allergic to iodine or have rare conditions including hypocomplementaemic vasculitis, dermatitis herpetiformis, or stage 4 or 5 kidney failure, and pregnant women with thyrotoxicosis should not take them¹⁵. If you are allergic to iodine or any of the other ingredients, or have one of those rare conditions, consult your doctor before taking them¹⁴.

Very young babies, under three months, and women more than six months pregnant should take the tablets as directed in the leaflet issued with them, but should afterwards be seen by their GP, who will arrange any necessary checks by a paediatrician¹⁵. For the full picture on supply, doses and local arrangements, see Stable Iodine Tablets: When to Take Them, Doses and Where to Get Them.

Who gets iodine tablets, and who does not

Stable iodine can only be prescribed and issued to individuals as part of nuclear off-site planning if there is evidence of a threat to health that requires this protective action¹⁶. That condition is not met everywhere. At Hinkley Point B in Somerset, the council reports that radioactive iodine levels have been declining since generation ended in August 2022 and are now at negligible levels, so stable iodine tablets are no longer recommended as a protective action there¹⁶.

Around naval bases, the picture is different. In Southampton, most residential properties receive tablets from Royal Navy personnel or council staff distributing to the door, and if you are out when they call, the tablets are left with a leaflet telling you what to do¹⁴. Legislation requires people living up to 1.5km from an operational berth to be given prior information about a nuclear emergency¹⁴. Portsmouth's booklet runs to July 2027, and Southampton's to July 2027⁷.

Schools and nurseries inside these arrangements hold tablets for the children in their care. In Southampton, named schools and nurseries just outside the incident area hold stable iodine tablets for all children and staff¹⁴. In Portsmouth, St George's Primary School, Portsmouth Grammar School and Top Tots Day Nursery in the John Pounds Centre hold tablets for all children and staff and will look after children in an incident⁷.

If you live near a site and have not received a booklet or tablets, do not assume you need them. Check with your council's emergency planning team, and read Living Near a Nuclear Site: Emergency Planning Zones and Information Booklets and Radiation Emergency Plans at Portsmouth, Devonport and Southampton.

Leave children at school: they will be cared for there

The instinct to drive to the school gate is strong and, in a radiation emergency, usually wrong. Portsmouth's resident guidance is explicit: going to collect your children may expose you and them to radiation, and the school will look after them and contact you when it is safe for children to leave⁷. Warwickshire's advice is the same: do not collect children from school unless you have been told to do so, because they will be properly cared for⁵.

Schools have plans for this. If a school needs to be evacuated, children will be taken to a safe place nearby and the school will contact you to let you know what to do¹⁷. In the Portsmouth area, schools more than 1.5km from the naval base will be told about incidents by the council and will look after pupils living within the 1.5km zone whose parents cannot collect them⁷. Southampton operates a similar arrangement for pupils whose parents live within the zone¹⁴. Schoolchildren are treated as a priority group, looked after either at the school or at a safe place by school staff and those responding to the emergency¹⁵.

What you should do instead is make sure the school can reach you. Check that your child's school has the correct contact numbers for you, and that it has plans for emergencies such as severe weather, loss of utilities and fire¹⁰. Do that now, before anything happens. For the detailed reasoning, see Should You Collect Children From School in a Radiation Emergency?.

Getting help and asking about tablets

If you have a question about whether to take stable iodine tablets, or any other health concern during an incident, the route is NHS 111. Council booklets tell residents to contact the NHS helpline on 111 with any queries about taking the tablets⁷, and Portsmouth's guidance says to call 111 or go to www.111.nhs.uk for health issues¹³.

NHS 111 online can be reached at 111.nhs.uk or through the NHS App on a smartphone or tablet, and there is British Sign Language access through SignVideo and text relay on 18001 111¹⁸. Easy read and large print guides to NHS 111 are available if you need them¹⁹. In Scotland the non-emergency number is NHS 24 on 111²⁰.

For households that need extra help, such as older or disabled residents or people who rely on medical equipment, plan now for who checks on them and how. Write down contact details of anyone who might need checking on, and a list of any regular medication and doses¹⁰. The Extra Help in an Emergency: Older, Disabled and Medically Dependent Households guide covers this in more detail.

Keeping the checklist ready before you need it

A checklist is only useful if the things on it are already in the house. The core kit for sheltering is modest: your household emergency plan with contact numbers, a battery torch with spare batteries or a wind-up torch, a first aid kit, important documents, bottled water and ready-to-eat food that will not go off, spare keys, spare glasses or contact lenses, toiletries and details of important medicines, a pencil and paper, a penknife and whistle, and pet supplies²². A first aid kit should include waterproof plasters, bandages, a thermometer, antiseptic, eyewash solution, sterile dressings and gloves, medical tape and tweezers¹⁰.

If you have a baby, add infant formula milk, disposable nappies and nappy sacks⁹. If you have pets, add pet food and treats⁹. Keep toiletries, hand sanitiser and wet wipes for hygiene²³.

If you are ever told to evacuate rather than shelter, the packing list is different: get your family and pets together, pack warm clothing and bedding, medicines or special food, baby food, clothes, nappies, toys and books, and private documents and valuables such as bank books and passports, make sure fires are out and appliances are switched off and unplugged, then lock up and leave¹³. For the choice between the two, see Radiation Emergency: Should You Shelter or Evacuate?.