What Is a Dangerous Radon Level?

https://whatisdangerousradonlevelworks.greyhavendaily.com/posts/what-is-a-dangerous-radon-level-a-homeowner-s-guide-to-understanding-the-risks

Radon is a radioactive gas that can seep into homes from the ground. The U.S. Environmental Protection Agency recommends taking action if your indoor radon level is 4 picocuries per liter (pCi/L) or higher. Levels below 2 pCi/L are considered low risk, while any level above 2 pCi/L is worth addressing to reduce potential health risks. Testing your home is the only way to know for sure.