FAQs on radiation exposure and health

  • What is radiation?

    Radiation is energy that is transmitted in the form of waves or particles. Scientists divide radiation into two broad categories –ionising radiation, and non-ionising radiation. 

    Ionising radiation is a proven hazard because it has enough energy to break apart molecules such as DNA which may, in time, lead to cancer. Non-ionising radiation does not have enough energy to cause such damage. 

  • Where are we likely to come across ionising radiation?

    We encounter ionising radiation constantly.  It occurs naturally in rocks and soil, in the food and water we eat and drink, and bombards the earth’s atmosphere from outer space.  It is produced artificially, and widely used in medicine, industry and research.  It is used in X-rays, in radiotherapy to treat cancers, in smoke detectors, and in many industrial processes.  The production of electricity from nuclear power generates ionising radiation as a by-product.

  • Where do we come across non-ionising radiation?

    Non-ionising radiation is generated by everyday energy sources, including light, heat, TV and radio signals, mobile phone signals, microwaves, and electro-magnetic fields associated with power lines.  The Department of the Environment, Climate and Communications are currently responsible for the health effects of non-ionising radiation including electromagnetic fields. 

  • Can ionising radiation be avoided?

    Ionising radiation has been with us since the birth of the universe.  Even if we could avoid artificially created radiation, we would still be exposed continuously to natural sources of ionising radiation.  Because it is present in the soil, we consume it in our food and water.  One type of natural radionuclide is radon gas that rises up from the ground  and we inhale it from the air when we breathe. We cannot avoid exposure to ionising radiation – but we can minimise our exposure to excessive dose from it. 

  • How does ionising radiation affect the human body?

    Ionising radiation transfers some of its energy to the atoms and molecules of the body, liberating electrons and so breaking molecular bonds. The effects of ionising radiation on the human body depend on the quantities of ionising radiation received. 

    High doses  destroy human cells at a faster rate than they can be replaced by natural regeneration in the body. This is called necrosis and can cause radiation sickness leading to serious illness and death, but it can also be applied to small volumes in the body to kill diseased cells such as cancers. Radiation sickness has been observed in workers exposed by accident to industrial sources, and people who spent time close to the site of nuclear accidents, such as the fire-fighters in the Chernobyl accident - Low doses above background levels increase the risk of cancer. The chemical changes caused by ionisation damage tissues, which do not always repair themselves properly. In time, poorly repaired tissue may become cancerous. For most people, estimating increased risk of cancer from radioactivity is difficult to distinguish from other sources of risk such as chemical pollution. 

    Where people are known to have been exposed to greater levels of radioactivity, their history of exposure may be used to estimate the increased risk cancer decades later. This has been applied to accident survivors, historic nuclear workers, and people exposed to elevated levels of radon either in their workplaces or homes 

  • Is there a proven link between ionising radiation and cancer?

    Yes, there is a scientific consensus that ionising radiation can trigger changes in human tissue that can, in some circumstances, mutate into cancer.  The risk rises in line with increased exposure to ionising radiation, in the same way that the risk of skin cancer grows with increased exposure to the sun’s rays. 

  • Is natural radiation less harmful than radiation from artificial sources?


    No. For a given amount of radiation, there is no difference between the harm caused by natural or artificial radiation.



  • What are the health risks from radon? 

    Radon is the second biggest cause of lung cancer in Ireland and worldwide after tobacco smoking.  Radon is responsible for around 300 lung cancer cases in Ireland every year. 

  • Does smoking increase the risk from radon-linked lung cancer?

    Yes.  Like tobacco smoke, radon is classified as a Class A carcinogen.  The combination of tobacco and radon magnifies the risk of lung cancer. Smokers account for approximately nine out of ten radon-linked lung cancer cases in Ireland.  The radon risk to an active smoker is 25 times greater than to a lifelong non-smoker. 

  • Are X-rays dangerous?

    X-rays are a vital tool in medicine, ensuring the precise diagnosis of certain illnesses.  The radiation dose from a simple X-ray is extremely small and therefore the risk is correspondingly small. 

  • How many X-rays is it safe to receive?

    During a chest X-ray, the radiation dose received is comparable to two days normal background radiation exposure.  Therefore, the risk is very small and can be justified on the basis that an illness may go undiagnosed without the X-ray and may have a higher risk. 

  • What about more complex X-rays, such as CT scans? 

    The radiation dose from a chest CT scan is roughly the equivalent of that received from 250 chest X-rays.  Although substantially higher than the dose from a simple X-ray, the dose from a CT scan is still within acceptable risk limits.  The procedure will only be carried out if your consultant judges that the benefits outweigh any risk. 

  • Should I try to avoid X-rays?

    If the procedure is justified on medical grounds, the simple answer is no.  Pregnant women should be especially cautious, and should discuss the procedure in advance with a medical practitioner to ensure that any risk to the pregnancy is minimised. 

  • Is it dangerous to swim in the Irish Sea?

    Radioactivity has been monitored in the Irish Sea since 1982.  The levels found would have no significant health effect on the public whether sailing, swimming, or diving in the Irish Sea.  On-going monitoring has shown that discharges of radioactivity have diminished over time.  



  • Is it safe to eat seafood from the Irish Sea?

    Yes.  The consumption of fish and shellfish is the main way the Irish public are exposed to radiation from Sellafield.  EPA constantly monitors radioactivity in seafood from the Irish Sea. For people who eat very large quantities of fish and shellfish, we have calculated the radiation doses and found that they represent less than one four thousandth of the total annual average dose received by someone living in Ireland.  

  • Does air travel pose any radiation risk?

    The earth is permanently exposed to a stream of atomic particles, which originate from the solar system and beyond.  Frequent flyers, particularly airline crew on long-haul routes, can receive radiation doses comparable with those who work directly with ionising radiation.  Air operators are legally obliged to evaluate the risk to air crew. For casual flyers, any health risk from air travel is likely to be low. 

  • After Chernobyl, is it safe to visit Belarus or the Ukraine?

    Based on available dose assessments, it is generally safe to visit these countries.  In the area around Chernobyl itself, the more heavily contaminated areas have been sealed off to the public.  If you are in these countries for a prolonged stay it may be wise, as a precautionary measure, to avoid eating mushrooms, berries, fresh-water fish and game as these foodstuffs can concentrate radioactivity. 

FAQs on Radiation emergencies

  • What is Ireland’s plan for a nuclear emergency?

    There is a national plan in place to reduce the risk to the people in Ireland, following a nuclear emergency abroad. The plan is called the National Plan for Nuclear and Radiological Emergency Exposures and is known as the National Plan 

  • How would we know if the National Plan needed to be activated?

    Early Notification   

    There are two international early-warning systems in place. These are managed by the International Atomic Energy Agency and the European CommissionThese systems would quickly notify the Irish Government of any threat.   

    Ireland also has an agreement with the UK that the Department of Environment, Climate and Communications and the EPA would be informed directly in the event of a radiation emergency in Ireland or the UK.   

    The EPA has a 24-hour radiation monitoring network. This would automatically trigger an alarm if any unusual radiation levels are detected.   

    Assessing the risk   

    In the event of a nuclear emergency, Met Éireann would calculate wind speed and direction, and the likelihood of rainfall in any part of Ireland that the plume might reach. The EPA would use this information, along with all information available about the radioactivity that has been released, to assess the risk to people in Ireland.   

    The Department of the Environment, Climate and Communications will make the final decision on whether the National Plan needs to be activated.   

    Taking protective actions   

    The public will be alerted and advised through the media.  If there is a risk to the people in Ireland from the emergency, the most likely actions would be:   

    • Staying indoors until the radioactive cloud has passed over.   
    • Restricting the use of contaminated food, water and animal feed.   


  • How would the National Plan help?

    The National Plan would help to ensure that people in Ireland are provided with information about: 

    • what has happened, 
    • how they might be affected and 
    • what they need to do to protect themselves.  


    This in turn would reduce the potential long-term health risks to the Irish population.

  • Who is involved with the National Plan?

    The National Plan is coordinated by the Department of the Environment, Climate and Communications and involves a number of other government departments and agencies working together, including the EPA, and the main TV and radio stations.  


    The EPA would play a key role in implementing the National Plan in the event of a nuclear emergency. 

  • How do we know the National Plan would be effective?

    Regular training exercises are carried out to test the plan.  

    In addition, every organisation involved with the plan conducts its own specific drills and exercises to ensure that each individual part of the plan would be carried out with efficiency, if it was activated.   

  • What would happen after the first few days of the emergency?

    The National Plan would continue to operate for as long as required. In the meantime, you should continue to follow government advice.  

    In the first few days after the emergency, samples of grass, crops, soil and other environmental materials from around the country would be tested for levels of different types of radioactivity.   

    Monitoring would continue for weeks, months, or longer if necessary. The public would be kept fully informed and advised of any action they need to take to reduce the risk of radiation exposure.   

    There would be close monitoring of livestock and crops. If necessary, controls and restrictions would be put in place to protect the public from buying or eating unsafe food.   

  • What happens if people were exposed to harmful radiation in this emergency?

    This is very unlikely. Any radioactive contamination in Ireland that causes higher radiation levels than normal could result in slight increases in certain types of cancer in the years and decades following a nuclear incident. However, it is unlikely that we could detect an increase in cancer rates.    

  • How do I know how serious a nuclear emergency this is?

    The international nuclear event scale (INES) is used to communicate the importance of nuclear and radiological events to the public.  

    The International Nuclear and Radiological Event Scale (INES) is a seven-point scale, with Level 1 being the least significant, and Level 7 the most significant. Where an event is classified as Level 0 or ‘below scale’, this means it has no nuclear or radiological safety significance.   

      (insert image INES)  

    INES is used to classify nuclear and radiological accidents and incidents by considering three areas of impact:  

    • People and the Environment: this  considers the radiation doses to people close to the location of the event and the widespread, unplanned release of radioactive material from an installation.  
    • Radiological Barriers and Control: this covers events without any direct impact on people or the environment and only applies inside major facilities. It covers unplanned high radiation levels and spread of significant quantities of radioactive materials confined within the installation.  
    • Defence-in-Depth: this also covers events without any direct impact on people or the environment, but for which the range of measures put in place to prevent accidents did not function as intended.  

    Information on recent events and their INES rating is available from IAEA NEWS service.  

  • Where can I find the National Plan?

    The plan is available to download at this link

  • What should I do in a nuclear emergency?

    The aim of nuclear emergency planning is to reduce the exposure of people to harmful radiation following a nuclear emergency. Even though the risk is very low, our message to people is clear:  

    Go in, stay in, tune in  

    Staying indoors is one way of reducing exposure to radiation following a nuclear emergency abroad and this could be recommended for a few hours as a precaution. This would not lead to a national shutdown. Essential service workers could continue to carry out their duties.  

    In the hours following the emergency, updates would be provided to the people of Ireland, including specific advice for certain groups e.g. farmers.   

    If the advice to ‘go in, stay in, tune in’ is given you should:  

    1. Go in. Going indoors to your home, workplace or another indoor location could protect you from exposure to radiation and reduce your long-term cancer risk.  
    1. Stay in. You should remain indoors until advised by the authorities that the radioactive plume has moved on. This may take a few hours, depending on the nature of the accident, and the weather.  
    1. Tune in. TV and radio stations – both state and commercial – will be kept fully briefed about the emergency. By keeping an eye on the TV or an ear on the radio, you will be kept updated with the latest news and advice, and informed if any actions such as remaining indoors are necessary. Information will also be made available via the website, www.emergencyplanning.ie and various social media channels.  
  • Should I take iodine tablets?

    There is absolutely no need to take iodine tablets.  

    Staying indoors and following the up-to-date advice of the Irish Government is by far the most effective way of reducing your risk of exposure. 

  • What to do after the emergency is lifted?

    The biggest potential public health threat following the emergency would come from radioactive contamination of farming produce, particularly from leafy vegetables, meat and dairy products. If it were necessary the government would put controls and restrictions in place to protect the public from contaminated food.  

    The Department of Agriculture, Food and the Marine along with the EPA and the Food Safety Authority of Ireland would ensure that all foods available for sale are safe. If necessary, this could include destroying contaminated farm produce.  

  • Could drinking-water become radioactive?

    In the event of a nuclear emergency, drinking water would be monitored and analysed along with other foodstuffs. But it is highly unlikely that water supplies would be contaminated to levels that would require the government to restrict its use.  

  • Could I be evacuated during a nuclear emergency?

    No. Evacuation would not be necessary in Ireland as we are situated more than 100 km from the nearest nuclear power plant (on the west coast of the UK).

    Evacuation is only necessary in the immediate vicinity of a nuclear accident. 

  • Is a radiological emergency the same thing as a nuclear emergency?

    A radiological emergency is an incident or accident which has the potential to result in a person being exposed to elevated levels of harmful radiation known as ionising radiation.  

    While this could include a nuclear accident, the term radiological emergency is generally used for a more local issue. 

  • What kind of incidents might lead to a radiation emergency?

    Radiation incidents that could trigger an emergency can be broken down into three categories:

    1. An accident involving a radiation source regulated under licence by the EPA. Potentially dangerous incidents might include:
    • A fire 
    • A transport accident 
    • The collapse of a building 
    2. A deliberate criminal act or terrorist attack. This could include:
    • The detonation of a dirty bomb  
    • An arson attack on a building which contained a source of radioactivity 
    • The theft of a source of radioactivity 
    3. A major incident with widespread radiological consequences. Examples of such events might include:
    • An accident at a nuclear installation abroad 
    • The re-entry into the earth’s atmosphere of a nuclear-powered satellite 
    • An accident involving a nuclear-powered ship or submarine


  • What happens if a radiological emergency occurs?

    The scale of the response would depend upon the severity of the emergency and the level of potential danger to the public. 

    small-scale emergency, like a road traffic accident involving a radioactive source, could be managed locally by the emergency services, with advice from the EPA.  

    A severe radiological emergency could require the activation of the National Plan for Nuclear and Radiological Emergency Exposures. 

    An EPA Radiation Duty Officer rota is in place at all times (24 hours a day, 7 days a week), and ensures that a radiation expert is always available to advise emergency services or to advise the government on appropriate actions to deal with the emergency. The rota is circulated every month to An Garda Síochána and other relevant organisations. 

  • Who would be involved in tackling a major radiation emergency?

    A range of organisations would respond in the event of a major radiological emergency in Ireland. 

    These include: 

    • Government departments 
    • Local authorities 
    • Emergency services 
    • The Defence Forces 
    • Health Service Executive 
    • Met Éireann 
    • Food Safety Authority of Ireland 
    • EPA 
  • What would be the EPA’s role in a radiation emergency?

    The EPA would immediately be notified of any major incident involving radiation. Our broad responsibilities are: 

    • To provide advice to first responders at the site of the incident 
    • To assist with radiation monitoring 
    • To confirm the levels of radiation 
    • To assess the radiation risks posed 
    • To provide advice on protective measures and public safety 
    • To notify the relevant international organisations, if appropriate 

    While the chance of such an emergency occurring is very slight, there are plans in place to deal with them if they happen.  

    The EPA Nuclear and Radiological Emergency Plan sets out the EPA’s responsibilities under the National Plan.  It includes details on EPA’s preparedness arrangements, the EPA radiation emergency response structure and the roles of teams and individual staff members in responding to a radiological emergency.   

    For information regarding transport of radioactive material see:

    Transport of radioactive material  

    For information for Licensees see:

    Licensees planning for emergencies 

  • Where can I find further information?

    Check out other organisations involved in preparing for and managing nuclear and radiological emergencies. 

    Some of these organisations work with us here in Ireland. Others are based abroad.