Radon in Williamsburg Area Homes
An overview of the radon hazard including identification, risks, and necessary actions.
What is the Problem?
Radon is an odorless, tasteless radioactive gas that can cause lung cancer and other serious health effects. Average Radon levels in some Williamsburg area homes have been found to exceed EPA safe limits of 4 picocuries per liter of air (4 pCi/l). Alpha Energy Laboratories makes radon test kits and compiles results from radon testing by zip codes . From 2001 through 2020, 15% of homes tested in 23185 are above 4pCi/l and 39% in zip code 23188 are above 4 pCi/l.
Research done by the William & Mary Department of Geology suggests a local source for radon lies within the sediments of the Yorktown Formation, which is prevalent in Williamsburg. Geologic maps show where the Yorktown Formation sediments may be found.
Check out the video below for more information on radon:
Am I at Risk?
Current data show that homes built within and slightly above Yorktown sediments tend to contain higher radon levels than homes built elsewhere. In Williamsburg, homes built at elevations between 64 feet and 58 feet seem to have moderate risk of increased radon levels, and homes built below 58 feet are predicted to be at the greatest risk.
For part of her senior research, a geology major asked Williamsburg city homeowners to volunteer for a free home radon test in November 2020. She distributed twenty-seven 2-day test kits provided by the Virginia Department of Health to residents throughout the city. Although the number of tests was small, the results validated the risk map. As expected, a number of homes located in high-risk areas did not have radon in excess of 4 pCi/L because of building construction and mitigation methods.
Use the map below to find your home and assess your risk.
Radon Risk Assessment Map
I found my address: what do the colors mean?
Locations within the red area are predicted to be at a high risk of radon hazards.
Locations in the yellow area are predicted to have moderate radon hazards.
Locations in the light blue area are predicted to have low radon hazards. However, the only way to know the radon level in a home is acceptable is by testing.
My address is in one of the colored areas. What should I do next?
If your home is inside the red or yellow area on the map it could be that average radon levels exceed EPA safe limits. Your location in either of these areas does not necessarily mean that you are living with unsafe levels of radon. We only recommend that you test your home to make sure that you are not at risk for the health hazards that radon causes.
How can I test for radon?
Commercially available radon test kits are available for less than $50 so that homeowners can determine if they might have a radon problem. Virginia Department of Health currently is offering radon test kits for $3 and is a source of additional information. Some local home inspection businesses offer testing and consultation.
Useful links for more information:
Virginia Department of Health: http://www.vdh.virginia.gov/radiological-health/indoor-radon-program/
U.S. Environmental Protection Agency: www.epa.gov/radon
Data Sources
Geology based on new information by the authors and amendments to: Bick, K.F., and Coch, N.K., 1969, Geology of the Williamsburg, Hog Island, and Bacons Castle Quadrangles, Virginia: Virginia Division of Mineral Resources Report of Investigations 18, 28 p. James City County GIS Mapping Office, 2020, Parcel Data ArcGIS Layer Download of December 8. VGIN (Virginia Geographic Information Network), 2007, Orthophotography Digital Terrain Model 2-foot contour interval for James City County, Virginia: James City County Open Data Website, download of December 8, 2020.