Risk Estimates Copy

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The “known” (scientifically conclusive) health concern with radon is lung cancer. Recently revised EPA risks assessments estimate 21,000 Americans die annually from radon-induced lung cancer, 150% higher than the 1994 estimate. Research studies from around the world conclude that when inhaled, radon and its by-products damage the lung tissue, which can lead to lung cancer. However, several studies have produced preliminary findings that the health effects of radon may include other diseases such as Leukemia, Alzheimer’s, Parkinson’s, and thyroid cancer. [See References]

A number of uncertainties are associated with both the risk factor and the estimate of average residential radon exposure may be quantified in risk assessment. Examples of factors considered in the uncertainty analysis are:

  • The effect of age on radon risk.
  • Possible differences between homes and mines in terms of dose per unit exposure.
  • The effect of exposure-rate on radon risk.
  • The effect of mine exposures other than radon (silica dust, diesel fumes, etc.).
  • The relationship between radon risk and smoking.

Of these sources of uncertainty, the relationship between radon risk and smoking is often of the greatest concern because smoking is the leading cause of lung cancer. Although the data are presently limited, scientists at the National Academy of Sciences (NAS) assume that smoking multiplies the risk from radon exposure. Based on the EPA’s risks calculations, the risk of lung cancer from radon exposure is almost twenty times greater for a current smoker than for someone who has never smoked.

Figure 1-3
Risk Comparisons