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Radon in Howell County, Missouri

Howell 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 98 building tests here for 2008 to 2017: median 3.5 pCi/L, with 45.7% at or above EPA's 4 pCi/L action level (Missouri 30.7%, US 36.5%).

Zone 2
EPA radon zone (1993 county map)
3.5
median lab test, pCi/L (2008-2017)
45.7%
of lab tests at or above 4 pCi/L
98
buildings tested by labs, 2008-2017

Radon test results in Howell County

Radon test results on file for Howell County, MO, with state and national comparison
Test resultsPeriodTestsTypical result4 pCi/L or more
Radon testing laboratories2008-201798median 3.5 pCi/L45.7%
Missouri radon program20232median 2.0 pCi/Ln/a
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
Fulton County, ARZone 2250%
Oregon County, MOZone 2333.3%
Ozark County, MOZone 2450%
Douglas County, MOZone 210%
Texas County, MOZone 24819.3%
Shannon County, MOZone 2526.3%

The six counties with the nearest centers.

What to do about radon in Howell 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 Howell County address

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

Radon in Howell County: questions

What is the radon level in Howell County?

The median of the 98 laboratory tests reported for Howell County (2008 to 2017) was 3.5 pCi/L, and 45.7% 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 Howell County in radon Zone 1?

No. EPA's 1993 map puts Howell 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 Howell County compare with Missouri?

45.7% of laboratory tests in Howell 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 Howell 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 Howell 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 29091. County-level screening information, not a radon measurement of any building.