Studies of miners exposed to radon and its decay products provide a direct basis for assessing their lung cancer risk. The BEIR VI report, entitled Health Effects of Exposure to Radon,[1] reported an excess relative risk from exposure to radon that was equivalent to 1.8% per megabecquerel hours per cubic meter (MBq·h/m3) (95% confidence interval: 0.3, 35) for miners with cumulative exposures below 30 MBq·h/m3.[41] Estimates of risk per unit exposure are 5.38×10−4 per WLM; 9.68×10−4/WLM for ever smokers; and 1.67×10−4 per WLM for never smokers.[5]