What is the level of radon in which the EPA states to take action?

The Environmental Protection Agency (EPA) has established that a radon level of 4 picocuries per liter (pCi/L) is the threshold at which action should be taken. This standard is based on extensive research demonstrating that prolonged exposure to radon at or above this level significantly increases the risk of developing lung cancer. Mitigation measures, such as improving ventilation or sealing pathways, are recommended once radon levels reach or exceed this guideline to protect public health. Consequently, when considering radon assessment and safety measures, a concentration of 4 pCi/L is crucial for initiating further precautions and potential remedial actions.