What radon level does the federal EPA recommend taking remedial action?

The federal Environmental Protection Agency (EPA) recommends taking remedial action when radon levels are at or above 4 picocuries per liter (pCi/L). This threshold is based on substantial research indicating that radon exposure at this level increases the risk of lung cancer for individuals, particularly among smokers. The EPA recognizes that radon is a significant health risk and thus recommends steps to mitigate exposure when levels reach or exceed this guideline.

Lower levels of radon, such as 1 or 2 pCi/L, while still a potential health concern, are not deemed necessary for immediate remedial action, according to current EPA guidelines. The 6 picocuries per liter figure is above the established action threshold, indicating a higher risk but does not reflect the specific level at which the EPA advises intervention. Therefore, the 4 pCi/L level is the correct and widely accepted standard for initiating remedial measures.