Attempting to retroactively seal foundations to keep radon from the ground out of a home is largely ineffective. As the number of homeowners obtaining needed repairs increases, significant lung cancer risk reduction is being achieved in a voluntary, non-regulatory setting. State and local public health programs in Wisconsin to reduce exposures to radon in indoor air began more than 10 years ago. The report is a comprehensive, significance-weighted review of all the evidence. Lung cancer is the only known health effect.
Tobacco smoke is a co-carcinogen with radon.
Although tobacco smoke is by far the predominant cause of lung cancer, radon control is a way for former smokers and never-smokers to reduce their lung cancer risks. Radon testing, and home remediation for those confirmed to have elevated radon, are continuing at a steady rate in Wisconsin. Congress is continuing funding for outreach by the states. Public skepticism continues in some quarters, as for other environmental health concerns, but seems to be diminishing. Although the data are not for randomly selected homes, the distribution by zip code in the map agrees, but with higher geographic resolution, with the distribution by county in the US EPA map 5 of radon zones in Wisconsin.