3 Radon gas is a byproduct of naturally occurring uranium decay. Odorless, tasteless and invisible, it seeps into homes through cracks in foundations, pores in walls, floor drains or any areas exposed to the ground. Differences in pressure create a vacuum effect between buildings and the ground that draws radon into homes, where it can accumulate undiluted by outdoor air. The amount of radon in the soil beneath the house and the design of the house itself contribute to the variation of indoor radon levels. Knowing the radon level in a home is not possible without testing.
Levels can vary widely, even between houses directly adjacent to each other.
Information from reference 3. Radon may cause cancer in smokers and nonsmokers, but the risk to smokers is much greater. It is estimated that radon causes up to 30,000 deaths per year in the United States. The American Medical Association supports this recommendation. Millions of homes in the United States are estimated to have a high radon level.