What are the danger zones for Tennessee for radon?

Answer 1

Radon is found in at least small quantities almost anywhere. The site below lists the areas of concentration in Tennessee.

Answer 2

The Environmental Protection Agency shows all counties in Tennessee listed as either Zone 1, 2, or 3. Zone 1 (>4pCi/L) is the where the highest potential risk is possible and Zone 3 (<2pCi/L) counties are where the lowest potential risk exists. To produce these risk Zones the EPA took random radon tests in most counties in the US to arrive at average expected results. So even in a county that is labeled a Zone 3 (average levels below 2pCi/L) there is always the potential to find some readings higher than 4pCi/L, which is currently the EPA's action level to mitigate a home for radon. The EPA also makes this statement about radon levels, "Because there is no known safe level of exposure to radon, EPA also recommends that Americans consider fixing their home for radon levels between 2 pCi/L and 4 pCi/L."

So all counties in Tennessee have the potential for high radon levels, although some will have fewer than others. The only sure way to know if you are out of the danger zone is to test your home.