AARST_Radon_Reporter_Q32025_Single

28 | SEPTEMBER 2025 Only 13% of US counties had no radon test results greater than or equal to 4 picocuries/liter in 2008-2017. In 85% of these counties, less than 10 radon test results were reported. IT’S ALL ABOUT THE DATA Maximum Radon Levels Reported, US Counties, CDC EPHT, 2008-2017 Radon test data for the above map were provided for most states to CDC by radon labs - except KS and NJ, for which state agencies provided the data. EPHT’s Data Explorer is the online tool for accessing this and other radon test data. LESS THAN 4 pCi/L 403 ; 13% LESS THAN 4 pCi/L AND FEWER THAN 10 TESTS 336 ; 11% LESS THAN 4 pCi/L AND AT LEAST 10 TESTS 67 ; 2% GREATER THAN OR EQUAL TO 4 pCi/L 2382 ; 78% NO RADON TESTS 271 ; 9%