The cancer-causing radioactive gas 'Radon' is becoming a concern for homeowners. More than 62,000 homes in Ireland have been tested for radon so far. Almost 8,800 homes have already been identified as having high levels of radon above the acceptable level - some homes have had extremely high levels. So what is Radon? It is a naturally occurring radioactive gas that comes from the natural breakdown of igneous rock. It is brought into the house via cracks in the floors, walls,