Charlotte, North Carolina – A dangerous gas could already be building inside homes across central North Carolina as cool spring nights and early-season temperature swings keep windows closed, allowing radon—known as the “invisible killer”—to accumulate indoors within hours. The risk increases quickly when airflow is limited, especially during overnight cooling.
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, crawl spaces, and basements. North Carolina is considered a moderate- to high-risk state, with elevated levels frequently detected across Mecklenburg County and surrounding areas, where some homes exceed the EPA action level of 4 picocuries per liter.
In Charlotte and nearby communities including Concord, Gastonia, and Huntersville, homes with basements or crawl spaces are especially vulnerable this time of year. Spring weather patterns often lead residents to seal homes overnight, trapping indoor air and increasing radon buildup. The North Carolina Department of Health and Human Services warns that radon is the second leading cause of lung cancer in the United States, linked to about 21,000 deaths annually.
Radon exposure produces no immediate symptoms, making testing the only reliable way to detect it. Short-term test kits can return results within 48 to 96 hours, and mitigation systems can reduce indoor levels by up to 99 percent when properly installed.
Residents are urged to test homes now as conditions through April continue to support indoor buildup. Additional advisories may be issued as risks persist into early summer across the region.
