Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
Locations and reports
Radon Levels in Massac County, Illinois
EPA puts Massac County in Zone 3, its lowest radon zone, and only 3 radon tests from it are on file with CDC (2017). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
17.1%
26.6 pts below IL
- Massac
- 17.1%
- Illinois
- 43.7%
35 tests, 2007 to 2016
Median result
2.2pCi/L
Below action level
- Massac
- 2.2 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2007 to 2016
Tests reported
35
91st of 92 by tests
- Massac
- 35
- Cook
- 13,699
Reported to CDC before any fix, 2007 to 2016
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Rank in Illinois
88 of 92
Lowest quarter
- Massac
- 17.1%
- Stark
- 79.4%
By share, of 92 with 30+ tests
Read a result for Massac County
Starts at Massac County's median, 2.2 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.2 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Massac County's median reported result, 2007 to 2016.
The data
Massac County, At a glance
Massac County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 98% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Massac County, 2017
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 0.0% |
| 2015 | 0.0% |
| 2017 | 0.0% |
2017: 0.0%. Across these years the share ran from 0.0% to 0.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 3 tests were reported to CDC for Massac County over 2017, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor this house.
Measured: CDC tracking data. Figure above: 2017. Measured data period: 2005 to 2017 (every CDC figure on file).
Massac County, Compared
Massac County radon figures, compared
Calculated by Radon411Massac County's 35 reported tests over the 2007 to 2016 laboratory totals had a middle value of 2.2 pCi/L and a maximum of 9.6 pCi/L, and 17.1% reached 4 pCi/L. Illinois as a whole (102 Illinois counties, pooled) comes to 43.7%: 26.6 points higher than here.
The newest figure, in 2017, counts only 3 tests (0.0% at or above 4 pCi/L), too few to compare, so this reading uses the 35-test figure.
Among its state's counties it ranks 88th of 92 Illinois counties with 30 or more tests for the same period. Statewide for the same period, Stark County reported the highest share (79.4%) and Johnson County the lowest (12.2%).
Below the action level, 17 tests (48.6%) came in under 2 pCi/L, against 31.2% statewide, and 12 tests (34.3%) fell between 2 and 4, against 25.1% statewide. The busiest year on file was 2014, with 12 tests reported; the quietest, 2017, had 3.
EPA's 1993 zone map puts Massac County in Zone 3, a predicted county average under 2 pCi/L. USGS geology rates 98% of the county's land low radon potential.
Johnson County, the one bordering county with a figure for the same period, reported 12.2%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Massac County, Geology
The ground under Massac County
PredictedMost of the ground under Massac County is one class on USGS's geologic map: 97.9% of its land is low radon potential, with 2.1% moderate. 97.8% of it lies in the area the map calls Coastal Plain Province, 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 |
|---|---|---|---|---|
| Coastal Plain Province | Cretaceous marine sediments and Quaternary alluvium. | Low | 8 | 97.8% |
| Shawnee Hills Section | Unglaciated Ordovician to Pennsylvanian limestone, sandstone, and shale. | Moderate | 10 | 2.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Massac County beside the ground around it
Across Illinois 64.5% of the land is rated high; none of Massac County's is. Of the 5 counties that border it, 4 have more moderate-potential ground, Livingston County, KY the most at 98.5%.
The map rates the ground, not the air in any home.
Local help
Massac County, Local resources
Radon testing and mitigation in Massac County
- IEMA-OHS Radon ProgramIEMA-OHS Radon Program, run by Illinois Emergency Management Agency and Office of Homeland Security, licenses or certifies radon professionals and states the rule for disclosing radon when a home is sold, and answers questions about testing and mitigation in Illinois.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
- Professionals in Illinois339 professionals are listed in Illinois.
What Illinois's program says
- Phone
- (800) 325-1245
- Licensing of radon professionals
The Agency also licenses and regulates the individuals who provide radon measurement and mitigation to the public.
- Disclosure when a home is sold or rented
Illinois Radon Awareness Act - This is the legislation that requires the seller to provide to the buyer of any interest in residential real property the IEMA-OHS pamphlet entitled "Radon Testing Guidelines for Real Estate Transactions" and the Illinois Disclosure of Information on Radon Hazards.
What it means
Massac County, Questions
Questions about radon in Massac County
Are radon levels high in Massac County?
In 2017, 0.0% of the radon tests reported to CDC for Massac County, Illinois were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.6 pCi/L. Of 92 Illinois counties with 30 or more tests for the same period, 87 reported a higher share; pooled, the state comes to 43.7%.
Which counties border Massac County?
Massac County borders 5 counties: McCracken County, KY, Pope County, IL, Johnson County, IL, Livingston County, KY and Pulaski County, IL.
Products
Massac County, Products
Testing a home in Massac County
In Massac County, 17.1% of 35 tests reported to CDC over the 2007 to 2016 laboratory totals reached 4 pCi/L, against 43.7% pooled across Illinois. 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 Massac County.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
Monitor
RadonEye RD200 plug-in continuous radon monitor
- C-NRPP 2024/25: Approved
- Plug-in
- Bluetooth
- Alarm
- Screen, app
Method: Ion chamber
First reading: Within 10 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Massac County, Bordering counties
Counties bordering Massac County
Calculated by Radon411- Radon levels in McCracken County, KYEPA zone 3
20.0%at or above 4 pCi/L
Median 1.7 pCi/L · 25 tests · 2.9 points above Massac County
- Radon levels in Livingston County, KYEPA zone 2
18.8%at or above 4 pCi/L
Median 1.7 pCi/L · 16 tests · 1.7 points above Massac County
- Radon levels in Pulaski County, ILEPA zone 3
12.5%at or above 4 pCi/L
Median 1.3 pCi/L · 16 tests · 4.6 points below Massac County
- Radon levels in Johnson County, ILEPA zone 2
12.2%at or above 4 pCi/L
Median 1.8 pCi/L · 49 tests · 4.9 points below Massac County
- Radon levels in Pope County, ILEPA zone 2
0.0%at or above 4 pCi/L
Median 1.8 pCi/L · 8 tests · 17.1 points below Massac County
Massac County, Cities and towns
Cities and towns in Massac County
About 13,502 people live in Massac County by the Census Bureau's estimate for July 1, 2025, 639 fewer than in 2020 (−4.5%). That works out to 57 people per square mile of land. Its largest town, Metropolis, has 5,727 residents, 42.4% of the total. Together its 3 incorporated places hold 50.0% of those residents; the other 50.0% live outside any of them. Reported testing is thin here: 35 tests over 2007 to 2016, or 2.6 for every 1,000 residents (2025 estimate), where Illinois as a whole comes to 8.3.
From Metropolis to Joppa, CDC publishes no figure by town: each reads Massac County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Metropolis | 5,727 | −3.6% | 42.4% |
| Brookport | 691 | −4.4% | 5.1% |
| Joppa | 330 | −5.2% | 2.4% |
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).
Massac County, Homes
Homes in Massac County
Massac County is a place of houses on their own lots: 76% of its 6,824 homes are detached single-family houses, against 58% across Illinois. Half of its homes were built before 1975, close to Illinois' 1970: 30% date from before 1960 and 15% from 2000 or later. Owners live in 79% of the occupied homes (Illinois: 67%), so for most households a test and a fix are their own to order.
| Homes | Massac County | Illinois |
|---|---|---|
| Housing units | 6,824 | 5,443,501 |
| Detached houses | 76% | 58% |
| In buildings of 5 or more | 2% | 22% |
| Mobile homes | 16% | 2% |
| Built before 1960 | 30% | 38% |
| Built since 2000 | 15% | 16% |
| Middle year built | 1975 | 1970 |
| Owner-occupied | 79% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.