As we move into the new year, Protect Environmental is launching its National Radon Risk Search™ tool. This search tool accesses the most comprehensive compilation of radon test results in the country, representing more than 2.5 million data points from sources that include the Centers for Disease Control and Prevention (CDC), as well as our own internal testing data. A companion to this launch is the release of our National Radon Risk Index™, which utilizes the same data to rank radon risk in communities across the United States. Our belief is that by empowering communities with vital radon risk information, more action will be taken to prevent radon-induced lung cancer in the places where we live, work, and learn. Our plan is to update our index each year in support of National Radon Action Month.
Our index for 2022 is broken into five sections, with each section including a ranking of the top 10 communities. The sections include:
- Highest radon level recorded in a building tested within the community
- Average radon level of buildings tested within the community
- Percentage of buildings tested within the community with a radon level above the EPA action level
- Highest percentage of residential buildings characterized for radon risk within the community
- Lowest percentage of residential buildings characterized for radon risk within the community
Highest radon level recorded in a building tested within the community*
| County, State | Radon Level |
|---|---|
| Dallas County, Texas | 7,879.3 pCi/L |
| Litchfield County, Connecticut | 4,800.0 pCi/L |
| La Plata County, Colorado | 4,115.0 pCi/L |
| Wilkes County, North Carolina | 3,200.0 pCi/L |
| Oakland County, Michigan | 2,297.0 pCi/L |
| Lawrence County, South Dakota | 1,431.3 pCi/L |
| Bucks County, Pennsylvania | 1,398.9 pCi/L |
| Schuylkill County, Pennsylvania | 1,300.0 pCi/L |
| Montgomery County, Maryland | 1,287.1 pCi/L |
| Nevada County, California | 1,100.0 pCi/L |
Average radon level of buildings tested within the community*
| County, State | Radon Level |
|---|---|
| Hinsdale County, Colorado | 53.8 pCi/L |
| Custer County, South Dakota | 30.1 pCi/L |
| Mineral County, Colorado | 29.2 pCi/L |
| Lawrence County, South Dakota | 29.0 pCi/L |
| Knox County, Ohio | 23.6 pCi/L |
| Butte County, Idaho | 21.8 pCi/L |
| Forest County, Pennsylvania | 19.8 pCi/L |
| Mifflin County, Pennsylvania | 19.3 pCi/L |
| Lincoln County, Montana | 19.3 pCi/L |
| Klickitat County, Washington | 18.5 pCi/L |
Percentage of buildings tested within the community with a radon level above the EPA action level *
| County, State | Percentage |
|---|---|
| Roosevelt County, Montana | 93.8% |
| Emmons County, North Dakota | 86.2% |
| Clay County, Nebraska | 85.1% |
| Billing County, North Dakota | 85.0% |
| Sioux County, Iowa | 84.2% |
| Rock County, Minnesota | 83.8% |
| Webster County, Nebraska | 83.2% |
| Pembina County, North Dakota | 82.5% |
| Plymouth County, Iowa | 82.3% |
| Hand County, South Dakota | 81.8% |
Highest percentage of residential buildings characterized for radon risk within the community*
| County, State | Percentage |
|---|---|
| Johnson County, Iowa | 10.974% |
| Adams County, Illinois | 10.267% |
| Washington County, Iowa | 9.805% |
| Wayne County, Nebraska | 9.190% |
| Winnebago County, Iowa | 9.184% |
| Sioux County, Iowa | 9.154% |
| Collier County, Florida | 8.972% |
| Shelby County, Iowa | 8.842% |
| Dubuque County, Iowa | 8.783% |
| Transylvania County, North Carolina | 8.704% |
Lowest percentage of residential buildings characterized for radon risk within the community*
| County, State | Percentage |
|---|---|
| Hildago County, Texas | 0.003% |
| Cameron County, Texas | 0.004% |
| Ellis County, Texas | 0.007% |
| Stanislaus County, California | 0.008% |
| Caddo County, Louisiana | 0.008% |
| Yuma County, Arizona | 0.009% |
| Wichita County, Texas | 0.009% |
| East Baton Rouge County, Louisiana | 0.009% |
| Solano County, California | 0.010% |
| Bay County, Florida | 0.010% |
If you are interested in using the National Radon Risk Index for a news story or other public use, contact our press team for citation information and permitted usage.
*Due to regulatory requirements, communities located within the states of Kansas and New Jersey are not included in the National Radon Risk Index. The data points utilized for the index are county-level. Counties with less than 10 test results are not included in the index analysis. The mean average was used for reporting the average radon level for buildings tested within a community.
Calculation of radiation dose equivalents included with the National Radon Risk Search tool was based upon information obtained through the Agency for Toxic Substances and Disease Registry.
- S. Department of Health and Human Services Public Service, ABDR. Toxicological profile for radon. Atlanta, GA: Agency for Toxic Substances and Disease Registry.
Calculation of the index was based upon analysis of data representing more than 2.5 million data points compiled from the Centers for Disease Control and Prevention (CDC) and Protect Environmental.
- Centers for Disease Control and Prevention. National Environmental Public Health Tracking Network. cdc.gov/ephtracking
