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Missouri Radon Map and Levels by County

Missouri's counties span all three EPA radon zones. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

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  • Share at 4+ pCi/L

    30.6%

    5.1 pts below U.S.

    Missouri
    30.6%
    U.S.
    35.7%

    58,525 tests across 115 counties, 2008 to 2017

  • Rank among states

    21 of 47

    Middle of the states

    Missouri
    30.6%
    North Dakota
    59.3%

    By share, every state pooled the same way, 2008 to 2017

  • Counties in EPA Zone 1

    11 of 115

    Some at highest potential

    Zone 1
    11
    Zone 2
    97

    Most counties sit in Zone 2; Zone 1 is the highest potential

  • Highest county

    69.9%

    Atchison County

    Atchison
    69.9%
    Vernon
    8.8%

    Counties with 30+ tests, 2008 to 2017

Read a result for Missouri

Starts at EPA's action level

4.0pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 4.0 pCi/L

At or above 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. 30.6% of Missouri's reported tests reached 4 pCi/L, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Missouri, At a glance

Missouri at a glance

Predicted: EPA radon zone

115 of 115 counties classified

EPA classifies counties, not states. Of the 115 counties in Missouri with a zone, 11 are in Zone 1, 97 in Zone 2 and 7 in Zone 3.

  • Zone 1: Highest predicted potentialgreater than 4 pCi/L11 of 115 counties · 9.6%
  • Zone 2: Moderate predicted potential2 to 4 pCi/L97 of 115 counties · 84.3%
  • Zone 3: Lower predicted potentialless than 2 pCi/L7 of 115 counties · 6.1%

An EPA radon zone predicts a whole county. It is not intended to determine whether any individual home should be tested: homes with elevated levels occur in all three zones, and EPA recommends testing every home regardless of zone.

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

CDC test figures, county by county

CDC publishes Missouri's radon test figures by county: 115 of its 115 counties have one. Each one's share is in the county list.

How to read these figures

Missouri, Compared

Missouri radon figures, compared

Calculated by Radon411
Missouri, 2008 to 2017, laboratory
30.6%
of 58,525 tests at or above 4 pCi/L, pooled
Against the U.S.
−5.1points
35.7% pooled
Rank among the states
21 of 47
1 is the highest share
Counties with 30 or more tests
72
Highest
69.9%
Atchison County
Lowest
8.8%
Vernon County

Missouri pools to 30.6%: that share of 58,525 reported tests from 115 counties over the 2008 to 2017 laboratory totals reached EPA's action level. Nationally the pooled share is 35.7%: 5.1 points higher than here.

Among 47 states pooled the same way it ranks 21st, with Tennessee (33.3%) above it and Virginia (30.4%) below. Atchison County reports the highest share (69.9% of 103 tests) and Vernon County the lowest (8.8%); the most tests came from St. Louis County, 17,747 of them at 26.3%.

Across its 4 overlapping ten-year totals, the share went from 32.4% (2005 to 2014) to 30.6% (2008 to 2017), within 2 points, with 2005 to 2014 the highest at 32.4%. By band, 3 counties at 50% or more, 35 counties at 30% to 50%, 29 counties at 15% to 30%, 5 counties at 5% to 15%.

EPA's 1993 map puts 11 of its 115 classified counties in Zone 1; against that, 30.6% of the tests reported since reached 4 pCi/L.

Missouri ranked among 47 states by pooled share of tests at or above 4 pCi/L, 2008 to 2017, laboratory
StateRankCountiesTestsAt or above 4 pCi/L
Indiana16 of 479243,14838.9%
Maine17 of 471611,82537.6%
West Virginia18 of 475510,06137.5%
New Hampshire19 of 471015,60835.0%
Tennessee20 of 479531,06633.3%
Missouri21 of 4711558,52530.6%
Virginia22 of 4713153,19930.4%
New Mexico23 of 47293,72128.5%
Michigan24 of 4783114,40726.9%
Connecticut25 of 47825,57226.5%
Washington26 of 47398,20125.5%
Missouri's highest and lowest counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/L
Atchison County1 of 7210369.9%
Andrew County2 of 7215860.8%
Buchanan County3 of 7257552.9%
Saline County4 of 725549.1%
Lafayette County5 of 7218446.7%
Howell County6 of 7213845.7%
Cass County7 of 7298845.5%
Howard County8 of 726243.5%
Marion County9 of 7228241.8%
Barry County10 of 725541.8%
Vernon County72 of 72348.8%
Polk County71 of 727811.5%
Montgomery County70 of 724712.8%
Crawford County69 of 723414.7%
Phelps County68 of 7220414.7%
Missouri's counties with 30 or more tests, by their own share at or above 4 pCi/L, 2008 to 2017, laboratory
ShareCountiesTheir testsFor example
50% or more3836Atchison County, Andrew County, Buchanan County
30% to 50%3521,683Saline County, Lafayette County, Howell County
15% to 30%2934,974Audrain County, Scott County, Jasper County
5% to 15%5397Phelps County, Crawford County, Montgomery County
Under 5%00None
Missouri ten-year laboratory totals, pooled, against the United States
PeriodCountiesTestsAt or above 4 pCi/LUnited StatesChange from the row before
2008 to 201711558,52530.6%35.7%−0.2 points
2007 to 201611554,94630.8%35.8%−0.9 points
2006 to 201511548,47731.7%36.3%−0.7 points
2005 to 201411542,53032.4%36.0%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period. CDC publishes no state or national figure.

Missouri, Counties

Missouri counties by EPA zone

Predicted

The map of Missouri, then its 115 counties zone by zone, each with its reported share at or above 4 pCi/L and a report of its own.

Missouri radon map by county: EPA radon zones. Map of Missouri's 115 counties shaded by EPA radon zone: Zone 1 in red-orange, Zone 2 in amber, Zone 3 in pale sand. 11 in Zone 1, 97 in Zone 2, 7 in Zone 3.
Missouri radon map by countyEPA radon zones for Missouri's counties: 11 counties in Zone 1, 97 counties in Zone 2, 7 counties in Zone 3.A prediction for each county, not a reading of any home; elevated homes occur in all three zones.

The 12 highest in Missouri, 2008 to 2017

Zone 1: highest predicted potential11

Local help

Missouri, Local resources

Local resources in Missouri

Who to ask in Missouri: its radon program, test kits and professionals.

What Missouri's program says
Phone
573-751-6102
Email
radon@health.mo.gov

What it means

Missouri, Questions

Questions about radon in Missouri

Is radon a problem in Missouri?

Missouri has 115 counties on EPA's Map of Radon Zones: Zone 1, the highest predicted potential, for 11; Zone 2 for 97; Zone 3 for 7. Pooled from 115 counties, 30.6% of the 58,525 radon tests reported to CDC over the 2008 to 2017 laboratory totals were at or above 4 pCi/L, 21st of 47 states.

Which Missouri counties are in EPA radon Zone 1?

11 counties are in Zone 1: Andrew County, Atchison County, Buchanan County, Cass County, Clay County, Clinton County, Holt County, Iron County, and 3 more in the county table on this page.

Who does radon mitigation in Missouri?

Radon411's Missouri directory lists 27 radon businesses for testing, mitigation or both, each with the licensing list it was read from.

Which Missouri counties have the highest radon?

By the share of reported tests at or above 4 pCi/L, 2008 to 2017, laboratory: Atchison County 69.9% (103 tests), Andrew County 60.8% (158 tests), Buchanan County 52.9% (575 tests), Saline County 49.1% (55 tests), Lafayette County 46.7% (184 tests).

Which EPA region is Missouri in?

Missouri is in EPA Region 7: Midwest.

Products

Missouri, Products

Testing a home in Missouri

30.6% of the 58,525 tests reported to CDC for Missouri over the 2008 to 2017 laboratory totals reached 4 pCi/L: a short-term kit (2 to 90 days) gives a first answer in days, a long-term test the year-round average. A short-term kit (2 to 90 days) is the quick first check for a home in Missouri; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Missouri homes, compared

Explore

Cities in Missouri with their own page

Radon data is published by county, not by city. Each city page sets the figures of the counties the city lies in side by side.