Short-term kit
Radon Short Term Test Kit short-term charcoal radon test kit, lab fee included
- Lab fee included
Method: Charcoal
In home: 2 to 7 days
Locations and reports
Radon Levels in Marshall County, Oklahoma
EPA puts Marshall County in Zone 3, its lowest radon zone. Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Nearest county
8.9%
Oklahoma County, 111 miles
- Oklahoma
- 8.9%
- Oklahoma
- 12.6%
Share at 4+ pCi/L, 135 tests, 2006 to 2015
Ground above low
None
15.2 pts below Oklahoma
- Marshall
- 0.0%
- Oklahoma
- 15.2%
Share of land USGS rates moderate or high potential
Tests reported
0
None published
A home here needs its own test
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Read a result for Marshall County
Starts at EPA's action level
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
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 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.
The data
Marshall County, At a glance
Marshall County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
No CDC test figures here
CDC has published no radon test figures for Marshall County. Oklahoma County, 111 miles away, is the nearest county with a figure over the 2006 to 2015 laboratory totals.
Marshall County, Compared
Marshall County radon figures, compared
Calculated by Radon411CDC's county radon counts over the 2006 to 2015 laboratory totals cover 53 Oklahoma counties, and Marshall County is not among them: no year's figure and no ten-year laboratory total names it. Pooled across 53 Oklahoma counties, 12.6% of reported tests reached that level; across every county in the country with a figure, 36.3%.
The nearest counties with a figure are Oklahoma County (111 miles away) at 8.9%, Tulsa County (152 miles away) at 6.0% and Cherokee County (164 miles away) at 32.0%. Statewide for the same period, Delaware County reported the highest share (44.7%) and Tulsa County the lowest (6.0%).
EPA's 1993 map puts Marshall County in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 100% of the county's land low radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Marshall County, Geology
The ground under Marshall County
PredictedUSGS's geologic map puts all of Marshall County's mapped land in one class: low radon potential. 99.2% of it lies in the area the map calls Gulf Coast Plain, to which USGS gives a radon index of 8, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Gulf Coast Plain | Cretaceous shale, nonmarine sand and clay and marine limestone and clay. | Low | 8 | 99.2% |
| Central Texas/Gulf Coast Plain | Cretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite. | Low | 7 | 0.8% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Marshall County beside the ground around it
Across Oklahoma 0.6% of the land is rated high; none of Marshall County's is. Of the 5 counties that border it, 2 have more moderate-potential ground, Grayson County, TX the most at 85.4%.
The map rates the ground, not the air in any home.
Local help
Marshall County, Local resources
Radon testing and mitigation in Marshall County
- Oklahoma's radon programDepartment of Environmental QualityOklahoma's radon program answers questions about testing, mitigation and the rules in Oklahoma.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsAsk the program whether it has free or discounted kits, or compare kits you can buy.
- Compare kits
- See the Oklahoma directoryNo professionals are listed in Oklahoma yet. The state program can point you to registered testers and mitigators.
What it means
Marshall County, Questions
Questions about radon in Marshall County
Are radon levels high in Marshall County?
No CDC testing statistics are published here for Marshall County, Oklahoma yet. Of the 5 nearest counties with a figure, within 198 miles, the share of tests at or above 4 pCi/L runs from 6.0% to 44.7%.
Which counties border Marshall County?
Marshall County borders 5 counties: Johnston County, OK, Grayson County, TX, Bryan County, OK, Carter County, OK and Love County, OK.
Products
Marshall County, Products
Testing a home in Marshall County
No CDC figure names Marshall County; the nearest county with one, Oklahoma County (111 miles away), reported 8.9% of its tests at or above 4 pCi/L over the 2006 to 2015 laboratory totals, the only reading nearby until a test of this home. Zone 3 is the lowest label, yet homes at or above 4 pCi/L occur in every zone: a short-term kit (2 to 90 days) is the quick first check in Marshall County.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
MonitorX-Sense
XR0B-SR battery digital radon monitor with an alarm
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Alpha spectrometry
First reading: Within 24 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Marshall County, Bordering counties
Counties bordering Marshall County
Calculated by Radon411- Radon levels in Carter County, OKEPA zone 3
25.0%at or above 4 pCi/L
Median 1.5 pCi/L · 8 tests
- Radon levels in Grayson County, TXEPA zone 3
6.7%at or above 4 pCi/L
Median 1.1 pCi/L · 15 tests
- Radon levels in Bryan County, OKEPA zone 3
0.0%at or above 4 pCi/L
Median 0.6 pCi/L · 1 test
- Radon levels in Johnston County, OKEPA zone 3
No CDC figure for 2006 to 2015; its page reads it against its own neighbours.
- Radon levels in Love County, OKEPA zone 3
No CDC figure for 2006 to 2015; its page reads it against its own neighbours.
Marshall County, Cities and towns
Cities and towns in Marshall County
Marshall County is growing: the Census Bureau puts it at 16,255 residents on July 1, 2025, up 6.0% from 15,340 in 2020. That works out to 44 people per square mile of land. Its largest town, Madill, has 4,181 residents, 25.7% of the total. Together its 3 incorporated places hold 40.5% of those residents; the other 59.5% live outside any of them. CDC publishes no radon test count for Marshall County; across Oklahoma its counts for 2006 to 2015 come to 0.2 tests for every 1,000 residents (2025 estimate).
From Madill to Oakland, CDC publishes no figure by town: each reads Marshall County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Madill | 4,181 | +7.2% | 25.7% |
| Kingston | 1,480 | +3.7% | 9.1% |
| Oakland | 927 | +9.7% | 5.7% |
3 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).
Marshall County, Homes
Homes in Marshall County
Of Marshall County's 8,817 homes, 60% are detached houses, against 73% across Oklahoma; 36% are mobile homes. Half of its homes were built before 1985, close to Oklahoma's 1980: 10% date from before 1960 and 25% from 2000 or later. Owners live in 80% of the occupied homes (Oklahoma: 66%), so for most households a test and a fix are their own to order.
| Homes | Marshall County | Oklahoma |
|---|---|---|
| Housing units | 8,817 | 1,763,036 |
| Detached houses | 60% | 73% |
| In buildings of 5 or more | 1% | 12% |
| Mobile homes | 36% | 9% |
| Built before 1960 | 10% | 21% |
| Built since 2000 | 25% | 25% |
| Middle year built | 1985 | 1980 |
| Owner-occupied | 80% | 66% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.