Assessment of Risks from Radon in Homes

The Agency has updated the estimates of lung cancer risks from indoor radon based on the National Academy of Sciences (NAS) latest report on radon, the Biological Effects of Ionizing Radiation (BEIR) VI Report (1999).  EPA worked closely with the Science Advisory Board (SAB), an independent panel of scientific experts, to determine how best to apply the risk models developed by the BEIR VI committee.  The SAB's advice and recommendations were incorporated modifying and extending the methods and approaches used in BEIR VI to construct a single model yielding results midway between the results obtained using the two models preferred by the BEIR VI committee.  The Agency's updated calculation of a best estimate of annual lung cancer deaths from radon is about 21,000 (with an uncertainty range of 8,000 to 45,000), which is consistent with the estimates of the BEIR VI Report.  A single risk model also permitted the Agency to calculate a numerical estimate of the risk per unit exposure [lung cancer deaths per working level month (WLM)] which will be used to update estimated lung cancer risks from radon in various publications.

The following is an updated chart of the lifetime risk of lung cancer death per person from radon exposure in homes (excerpted from the updated radon risk assessment).

Figure 187: UPDATED chart of lifetime risk of lung cancer death per person from home radon exposure.

Radon Level (a)

Lifetime Risk of Lung Cancer Death (per person) from Radon Exposure in Homes (b)


Never Smokers

Current Smokers (c)

General Population

20 pCi/L

36 out of 1,000

26 out of 100

11 out of 100

10 pCi/L

18 out of 1,000

15 out of 100

56 out of 1,000

8 pCi/L

15 out of 1,000

12 out of 100

45 out of 1,000

4 pCi/L

73 out of 10,000

62 out of 1,000

23 out of 1,000

2 pCi/L

37 out of 10,000

32 out of 1,000

12 out of 1,000

1.25 pCi/L

23 out of 10,000

20 out of 1,000

73 out of 10,000

0.4 pCi/L

73 out of 100,000

64 out of 10,000

23 out of 10,000

(a) - Assumes constant lifetime exposure in homes at these levels.
(b) - Estimates are subject to uncertainties as discussed in Chapter VIII of the risk assessment.
(c) - Note: BEIR VI did not specify excess relative risks for current smokers.