With the BEIR VI model, the main health effect (nearly 75% of the death toll) is to be found at low radon concentration exposures, because most of the population (about 90%) lives in the 0–200 Bq/m3 range.[90] Under this modeling, the best policy is obviously to reduce the radon levels of all homes where the radon level is above average, because this leads to a significant decrease of radon exposure on a significant fraction of the population; but this effect is predicted in the 0–200 Bq/m3 range, where the linear model has its maximum uncertainty. From the statistical evidence available, a threshold exposure cannot be excluded; if such a threshold exists, the real radon health effect would in fact be limited to those homes where the radon concentrations reaches that observed in mines—at most a few percent. If a radiation hormesis effect exists after all, the situation would be even worse: under that hypothesis, suppressing the natural low exposure to radon (in the 0–200 Bq/m3 range) would actually lead to an increase of cancer incidence, due to the suppression of this (hypothetical) protecting effect.