Is Cape Girardeau County, MO a radon risk area?

EPA places Cape Girardeau County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Rank it against the rest of the country and Cape Girardeau County lands in the 59th percentile for radon potential.

Where Cape Girardeau County sits nationally

About 83,658 people live in Cape Girardeau County, Missouri, spread over 578.517 square miles. That works out to roughly 145 people per square mile. Rank 228 by population within its EPA zone puts Cape Girardeau County at the 78th percentile among zone peers. Cape Girardeau County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

Neither at the 4 pCi/L action level nor down at the roughly 1.3 pCi/L national indoor norm, Cape Girardeau County's Zone 2 prediction lands in the gap between the two. Middle-of-the-pack doesn't mean risk-free for any one Cape Girardeau County address — a moderate county average still leaves individual homes to test either side of it.

Testing and mitigation in Cape Girardeau County

Nothing about Cape Girardeau 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

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

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed Cape Girardeau County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.