Devices capable of detecting the radioactive gas have yet to be activated in thousands of homes
Hundreds of thousands of homes have not activated devices for protection against cancer-causing radon gas.
It has emerged that radiation experts and the Environmental Protection Agency (EPA) asked the Department of Housing to make activation mandatory two years ago.
That followed studies and a live trial that showed that adding a €125 attachment to enable the device to work would massively reduce the risk of radon entering homes.
Researchers said the move had “the potential to result in a significant reduction in the number of radon-related lung cancers in Ireland”.
The Department of Housing says it received the trial results and is reviewing the issue but that further research is needed.
“The department is continuing to engage with the EPA and industry stakeholders as part of this review,” a spokesperson said.
The Irish Cancer Society said it would welcome a change to the building regulations to provide further protections.
“The Irish Cancer Society wants to reduce people’s exposure to radon because radon is a serious, cancer-causing gas and exposure to it can cause lung cancer,” it said.
Radon is linked to around 350 lung-cancer deaths in Ireland each year and is the chief cause of lung cancer in non-smokers.
The naturally occurring radioactive gas is associated with underlying ground conditions in many parts of the country but it can become a health hazard in homes where concentrations are high.
Since 1998, building regulations have required new builds to have an under-floor membrane to help stop the gas rising into the property, along with a standby sump.
The sump is a pipe running from the foundations up to the footpath and is capped with a lid where it meets the surface.
Householders are meant to test their house for radon and, if necessary, activate the sump by removing the lid and attaching a pipe to roof level with a cowl on top, an addition priced at €125 in 2021.
The rate of household testing is low, however. In 2019, when the EPA ceased its centralised testing service, just over 60,000 homes had been tested in the previous decade.
Test kits cost €50-€60 and take three or four months to return a result. The kits are now offered by private firms, but there are no reliable figures for how many householders avail of them.
The EPA runs occasional awareness campaigns urging people to consult its online radon maps to see if they are in a high-radon area and, if so, to get their home tested.
However, the building regulations warn: “Houses with high concentrations of radon gas are not confined to these areas and can occur in individual dwellings in any part of the country.”
A trial was run by the EPA, University College Dublin and a private testing firm in a new housing estate in Wexford in 2020.
It found that activating the sump with the addition of an external vertical pipe alone reduced radon levels by 65pc.
Adding a cowl, which helps draw up the gas more effectively, cut the level by 75pc. It also reduced to zero the number of cases where levels exceeded the generally accepted safe limit of 200 becquerels per square metre.
The research team wrote that activating the sump in this way was a “highly effective, simple-to-install, low-cost and zero-maintenance method of reducing radon exposure in new Irish dwellings with the potential to result in a significant reduction in the number of radon-related lung cancers in Ireland”.
They compared the €125 outlay with the cost of alternative approaches.
“Testing a dwelling typically costs €50, while remediating a dwelling by installing an active sump typically costs €1,000,” they said.
“In contrast, a review prepared for the Geological Survey of Ireland estimated that in 2016 the economic cost of radon-related lung cancers was just under €350m.”
The EPA said it had advised the Department of Housing of its research and recommendations and was continuing to engage with officials.
Around 600,000 houses have been built in Ireland since 1998. Most older homes have less protection against radon.