Table 1. Summary information of the radon exposures in the 11 miner cohort studies.
| Cohort | Metal type | Mean first year exposed | Mean duration (y) | Mean radon exposure (WLM)a, c | Mean concentration (WL)a, c | βradon, i (%) |
|---|---|---|---|---|---|---|
| China | Tin | 1955.6 | 12.9 | 286.0 | 1.7 | 0.16 |
| Czechoslovakia | Uranium | 1951.0 | 6.7 | 196.8 | 2.8 | 0.34 |
| Coloradob | Uranium | 1953.0 | 3.9 | 578.6 | 11.7 | 0.42 |
| Ontario | Uranium | 1963.8 | 3.0 | 31.0 | 0.9 | 0.89 |
| Newfoundland | Fluorspar | 1954.1 | 4.8 | 388.4 | 4.9 | 0.76 |
| Sweden | Iron | 1934.1 | 18.2 | 80.60 | 0.4 | 0.95 |
| New Mexico | Uranium | 1965.6 | 5.6 | 110.9 | 1.6 | 1.72 |
| Beaverlodge (Canada) | Uranium | 1962.6 | 1.7 | 21.2 | 1.3 | 2.21 |
| Port Radium (Canada) | Uranium | 1952.3 | 1.2 | 243.0 | 14.9 | 0.19 |
| Radium Hill (Australia) | Uranium | 1956.0 | 1.1 | 7.6 | 0.7 | 5.06 |
| France | Uranium | 1956.8 | 7.2 | 59.4 | 0.8 | 0.36 |
| Total | 1954.0 | 5.7 | 164.4 | 2.9 |
aWeighted by person-years; includes 5-year lag interval.
bExposures limited to < 3,200 WLM.
cOne working level (WL) is defined as any combination of short-lived radon progeny per liter of air that releases 1.3×105 million electron volts of alpha energy in decay. The ventilation was often poor in old uranium mines, and the radon progeny was approximately equilibrium with the radon itself. Under these conditions, each WL of radon progeny would correspond to 100 pCi/L of radon in air. Exposure to 1 working level (WL) for 170 h is defined as 1 working level months (WLM).