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Radon in Ray County, Missouri

Ray County, Missouri, is in EPA radon Zone 2: predicted average indoor radon screening level from 2 to 4 pCi/L (moderate potential). Radon laboratories reported 82 building tests here for 2008 to 2017: median 2.5 pCi/L, with 38.9% at or above EPA's 4 pCi/L action level (Missouri 30.7%, US 36.5%).

Zone 2
EPA radon zone (1993 county map)
2.5
median lab test, pCi/L (2008-2017)
38.9%
of lab tests at or above 4 pCi/L
82
buildings tested by labs, 2008-2017

Radon test results in Ray County

Radon test results on file for Ray County, MO, with state and national comparison
Test resultsPeriodTestsTypical result4 pCi/L or more
Radon testing laboratories2008-201782median 2.5 pCi/L38.9%
Missouri radon program20237median 2.0 pCi/L28.6%
Missouri, all counties (labs)2008-201742,913n/a30.7%
United States (labs)2008-20171,408,802n/a36.5%

Test results describe buildings whose owners chose to test and whose results reached the lab or agency, not a random sample; small counts swing widely. State and US shares are computed from county counts and percents. The laboratory data comes from national radon testing laboratories and supplements EPA's zone map.

Radon in nearby counties

CountyEPA zoneLab tests4 pCi/L or more
Lafayette County, MOZone 214646.7%
Clay County, MOZone 12,79439.2%
Caldwell County, MOZone 2166.3%
Carroll County, MOZone 21733.3%
Jackson County, MOZone 14,93641.3%
Clinton County, MOZone 19438.1%

The six counties with the nearest centers.

What to do about radon in Ray County

Test the building. EPA recommends fixing a home at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, and says there is no known safe level of exposure. Missouri's state radon program can point you to testers and test kits.

Buying here? The Environmental Records Report lists this county's radon zone and test results with the flood zone, mapped faults, power lines and federal contamination records near the address.

Check one Ray County address

Environmental Records Report, $29. PDF and JSON, usually ready in about a minute.

Radon in Ray County: questions

What is the radon level in Ray County?

The median of the 82 laboratory tests reported for Ray County (2008 to 2017) was 2.5 pCi/L, and 38.9% of them were at or above 4 pCi/L. These are results of tested buildings; a single home can be far above or below them.

Is Ray County in radon Zone 1?

No. EPA's 1993 map puts Ray County in Zone 2 (predicted average indoor radon screening level from 2 to 4 pCi/L (moderate potential)). EPA says homes in every zone can have high radon and should be tested.

How does radon in Ray County compare with Missouri?

38.9% of laboratory tests in Ray County were at or above 4 pCi/L for 2008 to 2017, against 30.7% across Missouri (42,913 tests) and 36.5% nationally. 11 of Missouri's 115 counties are in Zone 1.

Should I test for radon in Ray County?

Yes. EPA recommends testing every home whatever its zone: "This map should not be used to determine if individual homes need to be tested." Fix the home at 4 pCi/L or more and consider a fix between 2 and 4 pCi/L; EPA says there is no known safe level of radon exposure.

More for Ray County

Other free hazard lookups

All of these, plus wetlands, FEMA hazard ratings and the federal contamination lists, are in the Environmental Records Report for any US address ($29).

Radon in every Missouri county · Radon map of every state

Data compiled 2026-10-20. County FIPS 29177. County-level screening information, not a radon measurement of any building.