Radon is the second leading cause of lung cancer in Ireland. It has no smell, no colour, and no taste. You will not know it is there unless you test.

The Environmental Protection Agency estimates that radon is responsible for approximately 250 lung cancer deaths in Ireland every year. That is not a worst-case projection. That is the working figure. The gas seeps up through soil and rock, enters through gaps in floors and foundations, and accumulates indoors. A draughty old farmhouse can have lower levels than a well-insulated modern build, because airtight construction traps radon more effectively. Efficiency and exposure can go hand in hand.

Ireland sits on geology that produces radon at above-average rates compared to most of Europe. Granite-heavy areas are particularly prone. This is not a niche problem for remote rural houses. It affects suburban estates, offices, schools, and workplaces across the country.

Which Areas Are High Risk

The EPA publishes a radon map of Ireland that shows radon risk by area. High-radon areas include significant parts of Carlow, Galway, Kilkenny, Laois, Offaly, Sligo, Tipperary, Waterford, and Wexford. Parts of Wicklow, Clare, and Mayo also have elevated readings.

The map gives you a probability figure, not a guarantee. A house in a low-risk area can still have high radon levels, and a house in a high-risk area might test clean. The geology matters, but so do the specific construction details of your building. There is only one way to find out what is actually happening inside your home.

How EPA Radon Testing Works

The standard approach uses long-term passive detectors, sometimes called radon detectors or alpha track detectors. The EPA supplies these through its national radon measurement programme. You order them online, place them in two rooms in your home (one living area and one bedroom), leave them in place for at least three months, then post them back for laboratory analysis. Results come back in writing.

Three months is the minimum. Radon levels vary with seasons, weather, and ventilation patterns. A short-term test gives you a snapshot. A long-term test gives you a meaningful average. The EPA recommends testing over the winter months when windows are closed more often, which reflects real living conditions more accurately.

The cost is modest, around 50 euro for two detectors through the EPA programme. Given that the alternative is not knowing, it is not a difficult decision to justify.

The reference level in Ireland is 200 becquerels per cubic metre. Above that, you are expected to act. The EPA advises that any level above 100 Bq/m³ should be taken seriously in a home where people spend significant time. The average Irish home sits around 80 Bq/m³. Homes in high-radon areas routinely come back at 400, 600, or over 1000 Bq/m³.

What Happens if Your Levels Are High

Remediation is not complicated, and in most cases it is not expensive. A radon sump is the standard fix. A contractor drills through the floor, installs a pipe with a small fan, and draws radon out from beneath the building before it can enter. A properly installed sump can reduce radon levels by 80 to 95 percent. Most systems cost between 800 and 1500 euro for a typical home.

Other measures include:

Positive pressurisation systems. A fan draws clean air from the roof space and pushes it into the house, keeping air pressure slightly positive and preventing radon from being drawn upward through the floor. These work well in certain building types.

Sealing entry points. Gaps around pipes, cable entries, and sumps in suspended floors can be sealed. This is rarely sufficient on its own for high levels but supports other measures.

Natural ventilation improvements. Increasing underfloor ventilation in older suspended timber floor houses can make a difference. Modern builds with airtight construction need active solutions.

After any remediation work, you retest. Leave the detectors in place for another three months and confirm the levels have dropped. If the first round of work has not brought you below 200 Bq/m³, a second measure is added. There is no situation where remediation options run out.

Radon in the Workplace

This is not only a domestic issue. The Safety, Health and Welfare at Work Act 2005 and associated regulations place a legal duty on employers to assess radon risk in workplaces. If your premises is in a high-radon area or below ground level, testing is not optional, it is a compliance requirement. The HSA can inspect for this. Workplaces that test above the occupational reference level of 400 Bq/m³ must take action.

Basements, ground floor offices, school classrooms, and agricultural buildings are all relevant. If you run a business from a converted outbuilding or an older commercial property in a radon-risk county, this applies to you.

The Grant Scheme

SEAI and the EPA have at various points offered grant support for radon remediation works. Check the current position directly with both bodies, as schemes open and close. SEAI's home energy grants have been broadened over time, and radon remediation has been included under some schemes as an ancillary works category. Even without a grant, the cost of a sump installation is a fraction of what long-term radon exposure costs.

The gas accumulates over years. Lung cancer from radon typically takes decades to develop. That delay is exactly why people do not treat it as urgent. It is the same logic that allows people to ignore asbestos in Irish buildings until someone starts drilling. The harm is invisible and deferred. The action required is not.

Test first. Remediate if needed. Retest to confirm. The EPA makes this as straightforward as any health intervention in Ireland.

If you are in a high-risk county and you have never tested, that is your next step. The detectors cost less than a restaurant meal for two.