Blog › 2026-10-21
Radon Health Risks: What Upstate Homeowners Should Know
Radon is easy to ignore. You can't see it, smell it or feel it, and it doesn't cause headaches or coughing. That's what makes it worth understanding. Everything below comes from U.S. EPA and the U.S. Surgeon General, with no scare tactics or made-up numbers.
The key facts
- Radon causes lung cancer. EPA identifies radon as the leading cause of lung cancer among non-smokers and the second leading cause of lung cancer overall in the U.S., after smoking.
- EPA estimates about 21,000 lung cancer deaths a year in the U.S. are radon-related, about 2,900 of them among people who have never smoked.
- There are no warning symptoms. Radon exposure doesn't cause short-term symptoms like headaches or nausea. The harm builds up over years.
- Risk depends on level and time. The higher the radon level and the longer you breathe it, the greater the risk.
- Smoking multiplies it. EPA notes that smokers exposed to radon face a much higher risk than non-smokers at the same level.
- There's no known safe level. That's why EPA recommends fixing at 4 pCi/L and considering a fix between 2 and 4 pCi/L.
How radon harms the lungs
Radon is a radioactive gas from the natural breakdown of uranium in soil and rock. When it decays, it forms tiny radioactive particles that can lodge in the lining of the lungs when you breathe. As they continue to decay, they release small bursts of energy that can damage lung tissue and, over time, lead to lung cancer.
Why this matters here
Greenville County is the only South Carolina county EPA lists in Radon Zone 1, its highest-potential category, and neighboring Spartanburg, Pickens and Anderson counties are Zone 2 (details here). Upstate homes also spend much of the year closed up for air conditioning or heat, and families spend most of their time indoors, so radon that gets in tends to stay in.
Who should pay extra attention
- Current and former smokers in the household
- Families who spend a lot of time in basements or ground-floor rooms, such as home offices, playrooms and bedrooms
- Children: EPA notes that children may be more sensitive to radiation exposure
- Anyone who has never tested, or tested before a remodel or basement finish
What about radon in water?
Homes on private wells, more common in rural parts of the Upstate, can have radon in water. EPA says most of the risk from waterborne radon comes from breathing radon released into the air during showers and other household use, and that the risk is generally much smaller than from radon entering through the soil. If you're on a well and your air test is high, ask about testing the water too.
What you can do, in order
- Test your home. Here's how, or book professional radon testing.
- If it's 4 pCi/L or more, fix it. Mitigation systems are proven and usually installed in a day. See radon mitigation in Greenville.
- If you smoke, quitting lowers your radon-related risk along with everything else.
- Retest every couple of years and after renovations.
This article is general information based on EPA guidance, not medical advice. If you have health concerns, talk with your doctor.
References: EPA, Health Risk of Radon; EPA, A Citizen's Guide to Radon.
Quick answers
Does radon cause symptoms?
No. EPA notes radon causes no immediate symptoms such as headaches. Its main health risk is lung cancer after long-term exposure.
What radon level is safe?
There is no known safe level. EPA recommends fixing homes at 4 pCi/L or above and considering a fix between 2 and 4 pCi/L.