Washington, D.C. – A dangerous gas could already be building inside homes along the East Coast as cool spring nights and shifting coastal temperatures keep windows closed, allowing radon—known as the “invisible killer”—to accumulate indoors within hours. The risk can increase rapidly overnight as homes remain sealed against lingering cool air and humidity.
According to the U.S. Environmental Protection Agency, radon is a radioactive gas that forms naturally in soil and enters homes through foundation cracks, basements, crawl spaces, and slab floors. The East Coast—from New England through the Mid-Atlantic and down into the Southeast—includes a wide range of radon zones, with elevated levels detected in both northern and inland areas.
Across major cities like New York City, Boston, Philadelphia, Washington, D.C., Charlotte, and Atlanta, homes with basements and crawl spaces are especially vulnerable during early spring. Coastal moisture and temperature swings often lead residents to keep homes sealed overnight, trapping radon indoors and allowing concentrations to build without detection.
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 along the East Coast are urged to test homes now as conditions through April continue to support indoor buildup. Free and low-cost test kits are widely available, and mitigation systems can significantly reduce indoor levels before risks increase into early summer.
