Is Iron County, MO a radon risk area?

Iron County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally that's the 75th percentile for radon potential — Iron County outranks 75% of every county EPA has rated.

How Iron County compares

About 9,420 people live in Iron County, Missouri, spread over 550.267 square miles. That works out to roughly 17 people per square mile. Rank 782 by population within its EPA zone puts Iron County at the 27th percentile among zone peers. EPA's geology-based Region 7 groups Iron County with 411 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Iron County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. Being in Zone 1 raises the odds Iron County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.

Testing and mitigation in Iron County

Nothing about Iron County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Missouri's state radon program

Iron County's test kit answers today; a Airthings radon monitor keeps answering for Iron County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

More on how this number was built

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Iron County carries, the zone explainer covers what it does and doesn't tell you about any one house.