)))epidemiological evidence shows a clear link between breathing high concentrations of radon and incidence of lung cancerRadon has been recognized as carcinogenic to humans at high concentrations, based on miners studies.With the BEIR VI model, the main health impact (nearly 75% of the death toll) is to be found at low radon concentration exposures, because most of the population (about 90%) lives in the 0-200 Bq/m3 range.http://en.wikipedia.org/wiki/Health_effects_of_radon#Beneficial_uses