Cincinnati, Ohio – A dangerous gas could already be building inside homes across the Ohio Valley as cool spring nights keep windows closed, allowing radon—known as the “invisible killer”—to accumulate indoors within hours. The risk can increase rapidly overnight as fluctuating temperatures lead residents to seal homes against lingering cold.
According to the U.S. Environmental Protection Agency, radon is a radioactive gas that forms naturally in soil and seeps into homes through foundation cracks, basements, and crawl spaces. The Ohio Valley—including Ohio, Kentucky, Indiana, and West Virginia—sits in a region with widespread moderate to high radon potential, with elevated levels frequently detected across river valleys and inland counties.
Across cities like Cincinnati, Louisville, Indianapolis, and Charleston, homes with basements are especially vulnerable this time of year. The region’s geology, including limestone-rich soil, can allow radon to move more easily into structures, particularly when homes are sealed overnight.
Health officials warn radon is the second leading cause of lung cancer in the United States, linked to about 21,000 deaths annually. The gas produces no smell or immediate symptoms, making testing the only reliable way to detect it.
Residents across the Ohio Valley are urged to test homes now as conditions through April continue to trap indoor air. Free and low-cost test kits are widely available, and mitigation systems can significantly reduce indoor levels before risks increase into early summer.
