EPA has published guidance that is available free to schools throughout the country. Call your state radon office for more information. Even if your school does fail the radon test, the problem can be corrected. Proven techniques are available that will lower radon levels and lower the risks of lung cancer from radon exposure. Radon enters homes most commonly through cracks in foundations, openings around pumps and drains, construction joints, and cracks in walls.
Radon is most concentrated in the lowest level of the home.
Radon may also be present in well water and can be released into the air in your home when water is used for showering and other household uses. Radon entering homes through water may be a small risk compared to radon entering through the soil. Whatever level it's a risk, but the lower the radon the less the risk. 4 and above is action level. Only in an enclosed area.