Ordinary concentrations of radon in the atmosphere are unavoidable and likely do not pose any danger. The gas becomes a serious threat when high concentrations build up within the poorly ventilated enclosures. It is particularly dangerous to smokers who are exposed to high concentrations. Thousands of home and commercial buildings have been built on top of concrete slabs containing such aggregates. As we have mentioned, the decay process of radon gas creates products which are dangerous to human beings.
Particles can enter the lungs with air, dust or smoke and irradiate healthy tissues.
This can lead to the formation of cancer cells, and explains why miners who smoke are twenty times more likely to get lung cancer than those who don't smoke. Radon gas can build up in our homes in two ways. It can percolate upward from mine workings or it may be carried along by water flowing through pipes, to be released in showers, sinks, bathtubs and washing machines. If radon accumulates in underground caverns, it can contaminate drinking water supplies. Radon is the leading cause of lung cancer in non-smokers who live in houses with high levels of the gas.