Radon, a naturally occurring gas that can cause lung cancer after prolonged exposure, gained a local headline when its detection last summer in the Old Vanderburgh County Courthouse pushed out a longtime haunted house. After completing mitigation efforts, officials have delivered an all-clear โ and a change.
First, a brief geology lesson: Radon comes from the soil, starting as uranium, which decays and turns into radium over billions of years. The radium eventually becomes radon, which can seep into groundwater and the air, where it is often found as a radioactive gas.
โYou canโt see it, you canโt smell it, you canโt really tell itโs around unless you test your home for radon,โ says Ryan Goelzhauser, radon measurement and mitigation provider with Popham Construction Co.
In August 2024, it was announced that heightened levels were detected in the air of the Old Courthouse. The Old Courthouse Foundation was working with Hafer on a comprehensive study of the buildingโs interior and exterior, and the superintendent at the time decided to conduct radon tests as well. Radon tests conducted by Environmental Management Consultants in January 2024 determined the radon levels to be unsafe in various areas of the building, especially in the sub-basement, where levels registered at twice the U.S. Environmental Protection Agencyโs recommended โaction levelโ of 4 picocuries per liter (pCi/L). Popham was brought in by March 2024 to install a mitigation system.
That produced a problem for the Olde Courthouse Catacombs, a popular scare house held for years in the sub-basement. Items from the attraction were removed from the basement starting in April and before mitigation efforts began, the catacombs moved to the lowest level of the haunted Main Street attraction House of Lecter.
Back at the old courthouse, Goelzhauser installed a radon mitigation system rea that had the highest average radon levels during the initial testing phase, which has mostly dirt floors.
โRadon mitigation is just the overall reduction of radon levels within a building,โ Goelzhauser says. โThe radon levels within the building have likely been fairly close to what they were for a long time. โฆ Buildings nowadays are built so tight that it basically traps radon within the building. If you donโt have some sort of system to keep it from getting in the building an to exhaust itย to the exterior, it build up to dangerous levels.โ
The sub-membrane depressurization system installed works by preventing the radon gas released from the ground from escaping into the air. Since radon escapes into the air through cracks in the earth, a soil gas mat and a vapor barrier โ essentially, a large white tarp โ are placed over the affected area. Goelzhauser says the system is 99 percent complete and has been on for a few weeks.
โSo far, it seems like itโs had a good effect on radon levels throughout the rest of the building,โ he says, adding that third-party testing still is need to confirm.
County officials, meanwhile, say they plan for the sub-basement to remain unoccupied, which, according to Goelzhauser, likely wouldnโt require further mitigation efforts. Only construction and maintenance crews will be allowed in the sub-basement.
โWeโre trying to … spend taxpayer dollars wisely while still being progressive in solving the problem of elevated levels of radon within the building,โ he says. โBased on what Iโm seeing right now, I think there is a very good chance that we can consider the problem solved without having to extend the system.โ
โWhere the building is occupied โฆ radon is not a real issue right now,โ County Commissioner Mike Goebel assured visitors during a Jan. 22 media day at the courthouse for National Radon Action Month.
Goelzhauser adds that older buildings can have more โpathwaysโ for radon to escape into the air or, like the courthouse, have dirt floors in certain areas. However, any structure can have heightened levels of radon exposure no matter its age and there are hotspots throughout the Tri-State where heightened radon levels are more likely to occur.
The EPA estimates around 21,000 people die from radon-related lung cancers per year. While the state of Indiana does not require radon testing for most real estate transactions, Goelzhauser says it is recommended every two years after an initial test if the levels are elevated and a radon mitigation system is installed. Tests can be done with a licensed professional or with a self-install kit available at a hardware store. Long-term radon testing also is recommended to watch the levels throughout the seasons. He also recommends testing for radon after construction or HVAC updates.
โThe more areas we can test for radon, the more lives we can save,โ Goelzhauser says. โEverybody needs to test their home for radon.โ
