Rn and non-Rn doses in U mines

In my previous posting (earlier today), I alluded to doses received by U miners from sources other than Rn progeny and their role in a systematic overestimation of radon risk. I have just been notified that I can quote my paper "Is the radon risk overestimated? Neglected doses in the estimation of the risk of lung cancer in uranium underground miners", which has just been accepted for publication in Radiation Protection Dosimetry. It will probably be published in Radiation Protection Dosimetry Vol 98 No 3 in March 2002. I tried to show that radon progeny contribute sometimes as little as 25% of the total lung dose and rarely contribute more than 50 or 60%. Rn risk is systematically overestimated, once by neglecting lung non-Rn lung doses - which can be, in some mines, estimated numerically, and once more by neglecting doses received in mines other than that considered in each specific cohort, which much more difficult to estimate numerically by can be many-fold when the duration of employment is of the order of the year. Both neglected non-Rn doses and other-mine doses contribute to overestimating Rn risk. This should be taken into account by those who extrapolate risk down to zero exposure.