Radon was discovered by the German physicist Friedrich Ernst Dorn in 1900.
It is a colourless and odourless gas formed by the decay of radium that is naturally present in the ground, sometimes in ground water and in a much lower concentration in the air.
Although it is a carcinogen (a substance that causes cancer), exposure to radon is only harmful in high concentrations. In fact, some people claim that exposure to low concentrations of radon is actually beneficial to one’s health.
The most likely scenario is that exposure to low concentrations of radon gas is negligible, while exposure to a high concentration can be fatal.