Why 40% of Pennsylvania Homes Fail Radon Tests

PA DEP estimates about 40% of Pennsylvania homes have radon above EPA’s 4.0 pCi/L action level. This video traces the geological forces behind that estimate—from the billion-year-old Reading Prong granite belt to Marcellus Shale deposits—and explains why certain regions face dramatically elevated risk. Learn what radon testing protocols exist, when mitigation is required, and how DEP-certified professionals assess and address elevated levels.

Source for the estimate: PA DEP, Radon Action Month release, January 12, 2026.