reproductive outcomes. This chapter updates the BEIR IV report's coverage of outcomes other than lung-cancer.

Interpretation of the epidemiologic findings on effects of radon other than in the lungs needs to be based on an understanding of the dosimetry of radon and its progeny. Dosimetric models used for this purpose have extended beyond deposition of progeny in the lung to distribution to and absorption in other organs. Although there has been little work on this aspect of radon dosimetry, the models suggest potentially important doses to skin and lymphocytes.

Table 4-1 shows estimated annual absorbed doses to various adult tissues from Rn-222 and its short-lived daughters, for a domestic concentration of 20 Bqm^-3 (0.54 pCiL^-1). The estimated dose for the basal cells in exposed skin depends heavily on assumed deposition velocity. The upper estimates are comparable with lung doses and might be responsible for a substantial number of skin cancers, most of which would be nonfatal. With assumptions of 125 µGy y^-1 to exposed skin of the face and neck, 7.5 µGy y^-1 to skin of all other regions, an RBE of 5 for alpha-