About 1 in 3 Ohio radon tests come back high. Map by ZIP

About 1 in 3 radon tests in Ohio homes since 2010 came back above 4 picocuries per liter, the level at which the U.S. EPA recommends fixing a home: 34.7% of 505,420 tests. In 147 ZIP codes, at least half of the tests did. These are homes somebody chose to test, before any fix, not a random sample, so the only way to know your own home is to test it.

Have you tested yours? What did it read?

Radon is one of dozens of things Cracked Buckeye maps for every Ohio ZIP code: tap water, schools, housing, broadband, hospitals, history and more.

Sources: Ohio Department of Health, radon test results by ZIP code, 2010 to 2026, before mitigation, reported by Ohio-licensed radon professionals; U.S. EPA, A Citizen's Guide to Radon (the 4 pCi/L action level).