EPA life time security requirements for carcinogens are established based upon a 1 in 100,000 risk of fatality. Most scientists concur that the threat of death for radon at 4 p Ci/L is around 1 in 100. At the 4 p Ci/L EPA radon action guid…

The best threat of radon direct exposure arises in buildings that are impermeable, insufficiently ventilated, and have foundation leakages that allow air from the dirt into basements and also house rooms. THAT presented in 2009 an advised …