In most cases however, radon entering the home through water is a small risk compared to radon entering your home through the soil. Radon is a cancer-causing, radioactive gas. The radioactive decay products of radon gas, can attach themselves to lung tissue when radon gas is inhaled. Since radon has a 3.8 day half-life, it is likely that when a radon atom is inhaled it will be exhaled again before it decays. However, as the radon concentrations increase, the quantity of radon gas that has the potential to decay while still inside your lungs also increases, thereby resulting in a greater health risk.
Alpha radiation emitted during the decay process presents the most significant risk to humans.
The energy released by alpha particles can cause permanent damage to DNA tissue in the lungs. Most of this damage can prevent further cell division, and eventually the cell will die. Small children are especially at risk. The level at which action should be taken to reduce radon levels in your home is in dispute, in some circles. Whichever side of the debate you find to be more credible, t here can be no argument that high radon levels pose a significant health risk .