Doses to Organs and Tissues >From Radon and its Decay Products
UK National Radiological Protection Board, Published in Journal of Radiological Protection (2002)

Under normal circumstances, the largest dose from radon and its decay products will be that to the lung, delivered by the decay products rather than radon gas. This suggests that, when considering the radiological impact of radon and its decay products, the conventional focus on the risk of lung cancer from inhaled radon decay products is appropriate.

Nevertheless, calculations suggest that the dose to the basal layers of the skin may also be high, with a consequent possible risk of skin cancer. Unless countermeasures are taken, a smaller number of people may also run a significant risk of stomach cancer from radon ingested in drinking water. Doses to other organs and tissues are smaller, though not necessarily negligible. The results presented here allow these risks to be quantified and compared.