The Phase II committee should formally evaluate sources of exposure error in the miner cohorts and the consequence of these errors for risk estimation and risk assessment.
The Phase II committee should consider new evidence on arsenic, silica, and other factors that can modify or confound the risks estimated from miner studies.
Formal analysis of uncertainties in extending risk models from miners to the general population should be undertaken.
The Phase II committee should evaluate possible risks of cancer at sites other than lung, particularly with the data from the pooled analysis of the miner studies in progress.
The Phase II committee must evaluate and interpret the results of case-control and ecologic studies that have been reported and of the forthcoming studies, including evaluation of the limitations and uncertainties in these studies.
Results of case-control studies reported thus far have generally been consistent with estimates based on extrapolation from data on underground miners but have not provided enough precision to rule out the possibility of no risk or of risks that are substantially larger than those obtained through extrapolation. The Phase II committee should determine the potential role of current and future case-control studies for validating risk models based on miners and more generally for developing risk models of residential exposure to radon.
The Phase II committee should make recommendations regarding whether it is desirable to initiate new case-control or ecologic studies of residential radon.