When Jim and his wife bought their home in Murfreesboro, they had done everything right. They hired an inspector, reviewed the disclosures, and asked the usual questions. Radon was not on their list. It was not on the inspector’s checklist either. A few months after moving in, a neighbor mentioned she had tested her home and the levels came back high. Jim borrowed a test kit and ran it in his basement. The result was 6.2 pCi/L. He had no idea what that number meant. Many Tennessee homeowners end up in the same spot. That is a good reason to understand what the research says about radon and lung cancer before you need to act.
Radon gas is invisible and odorless, and it occurs naturally in soil beneath homes across the country. The U.S. EPA links about 21,000 lung cancer deaths a year in the United States to radon. That makes it the leading cause of lung cancer among non-smokers and the second leading cause overall. The figure rests on decades of research and reflects the consensus of major public health agencies. A good starting point is what radon is and how it behaves.
For Tennessee homeowners, this is not abstract. Testing data from Davidson County found elevated radon in roughly 40% of a sample of more than 4,000 homes. That is why the EPA and the U.S. Surgeon General recommend testing every home, whatever its location, age, or construction.
Key Takeaways
How radon causes lung cancer: Radon decays into radioactive particles you inhale, and they deposit alpha radiation into lung tissue, damaging cells over time.
Scale of the problem: The EPA links about 21,000 lung cancer deaths a year in the United States to radon.
The top cause for non-smokers: Among people who have never smoked, radon is the single largest cause of lung cancer, per the EPA.
Smoking multiplies the risk: Smokers exposed to elevated radon face about 10 times the risk of non-smokers at the same level, per CDC data.
No symptoms means no warning: Radon produces no immediate symptoms, so testing is the only reliable way to know your home’s levels.
The action level is 4.0 pCi/L: The EPA recommends mitigation at or above 4.0 pCi/L and suggests weighing action in the 2.0 to 4.0 range.
The problem is fixable: A professional system can cut indoor radon by up to 99% in some cases, per the New York State Department of Health.
If you have questions about where to start or what a result means, Radon 1’s certified team can walk you through it. Many homeowners stand exactly where Jim did. Uncertainty about next steps is normal, and information costs nothing. Reach us at (615) 257-9818.
How Does Radon Actually Cause Lung Cancer?
Radon causes lung cancer through a physical process, not chemical toxicity. It is a radioactive gas that forms when uranium in soil and rock decays. As radon decays further, it releases radioactive particles called progeny. When you breathe those particles in, they can settle in the airways and emit alpha radiation into nearby tissue. That radiation damages the DNA in lung cells. Repeated exposure over months and years raises the chance that damaged cells turn cancerous, according to the World Health Organization.
The process is gradual, which is part of why radon is hard to perceive as a threat. Someone in a high-radon home feels nothing. The risk builds quietly, and it scales with both concentration and time. Higher levels over longer periods mean meaningfully higher risk. So the EPA treats radon as a long-term health concern, not an acute hazard, and points to testing and mitigation as the answers.
What Do the Statistics Actually Tell Us?
The EPA and public health agencies most often cite 21,000 radon-related lung cancer deaths a year in the United States. That places radon in a category most people do not expect. Radon-related lung cancer deaths outnumber deaths from drunk driving, drowning, and home fires each year.
The risk is not spread evenly. Smokers face a compounded threat. The CDC reports that smokers exposed to elevated radon have about 10 times the lung cancer risk of non-smokers at the same level. Smoking and radon damage lung tissue through different mechanisms, so the combined effect is more than additive. For a smoker in a home above the action level, the risk is far more serious than either factor alone.
For non-smokers, the picture is still significant. Measurable increases in lung cancer risk have been observed at radon levels around 2.7 pCi/L, which is below the EPA’s 4.0 pCi/L action level. This is one reason the EPA encourages homeowners to consider mitigation even when radon levels fall between 2.0 and 4.0 pCi/L, rather than waiting for them to rise higher. Understanding what constitutes a safe radon level helps put these numbers into perspective.
Who Is Most at Risk from Radon Exposure?
Radon puts every occupant of a high-radon home at risk. Some groups face more cumulative exposure simply from time spent inside. People who work from home, stay-at-home parents, children, and older adults all spend more hours at home on average. Public health agencies single out children for protective action, because they breathe faster and their tissues are still developing, even though the exposure mechanism is the same as for adults.
Smokers, again, carry a much higher risk once radon enters the picture. If your household includes current or former smokers, testing matters more, not less. The link between smoking and radon is one of the most important and underreported pieces of radon health data. It is worth understanding clearly before you decide how to respond to a result.
Homes with basements or lower-level living spaces tend to show higher radon, because those areas sit closer to the soil. Radon levels in basements often run measurably higher than upper floors. That is why EPA guidance directs testing at the lowest livable level.
Does Radon Exposure Show Any Warning Signs?
Radon exposure causes no symptoms. No cough, no shortness of breath, no fatigue, no physical sign that levels are high in your home. This is one of the most important facts about radon as a health concern. The only way to detect it is to measure it directly.
By the time a doctor diagnoses lung cancer and links it to radon, the risk has built for years. So the EPA frames testing and mitigation as the practical protection, rather than waiting for a sign that never comes. A short-term test takes 48 hours, and a long-term test runs up to a year. Either one tells you where your home stands. Understanding what radon test results mean is simple once you know the thresholds.
What Happens If Your Home Tests High?
A result above 4.0 pCi/L means action is recommended. The good news is that elevated radon is fixable. Sub-slab depressurization is the most common professional method. It draws radon from beneath the foundation and vents it outdoors before it reaches living spaces. Installed correctly by a certified contractor, these systems are highly effective. Some health department guidance cites reductions of up to 99% in certain installs, though results vary by foundation type and home.
Many homeowners weigh the cost and value of mitigation carefully, and the data supports it as a worthwhile investment. A professional system treats the source directly, and post-installation testing confirms the result. If your test comes back high, the right move is mitigation from a certified contractor, not endless retesting or a partial fix. You can also review what a full radon mitigation system includes before you begin.
Frequently Asked Questions
How does radon get into a home in the first place?
Radon forms in soil and rock as uranium decays and migrates upward as a gas. It enters homes through cracks in foundations, gaps around pipes, sump pits, crawl space floors, and porous building materials. Because indoor air pressure is typically lower than the pressure in surrounding soil, homes naturally draw in soil gases, including radon.
Is radon more dangerous in certain regions of the country?
The EPA publishes radon zone maps that classify counties by predicted radon potential, with Zone 1 representing the highest predicted levels. However, the EPA is clear that elevated radon occurs in all zones and all states, so testing is recommended everywhere regardless of local zone classification. In Tennessee, multiple counties fall in Zone 1 or Zone 2, and local testing data confirms that a meaningful percentage of homes in the region have elevated levels.
Can a radon mitigation system actually eliminate the health risk?
A properly installed and tested radon mitigation system significantly reduces radon concentration in your home, which reduces long-term lung cancer risk. No environment can be guaranteed to have zero radon, but bringing levels well below the EPA action level of 4.0 pCi/L addresses the meaningful portion of the risk. Post-mitigation testing confirms the system is working, and periodic retesting every two years ensures it continues to perform.
Does radon affect children differently than adults?
Children breathe faster than adults and spend more time indoors on average, which means their cumulative radon exposure in a given home is often higher. Public health agencies including the CDC recommend treating radon as a risk for all household members and taking action at elevated levels regardless of household composition. The protective steps are the same: test, mitigate if elevated, and retest to confirm results.
Is it worth testing if the home is newer construction?
New homes can have elevated radon. The EPA states that any home can test high regardless of age, construction type, or geographic location. Some new construction includes passive radon-resistant features, but those features do not guarantee low levels and should be followed up with testing after occupancy. The only reliable way to know a home’s radon level is to measure it directly.
If your home has not been tested for radon recently, or if a previous test came back above 2.0 pCi/L, the next step is to schedule a professional measurement with a certified technician. Radon 1 has installed more than 20,000 mitigation systems across Tennessee over more than 20 years, with teams serving Nashville, Knoxville, and Chattanooga. Every estimate includes materials, labor, and post-installation verification testing. If you are not sure where to start, that is a normal place to be. Our NRPP-certified team is glad to answer questions and help you figure out the right next step. Reach us at (615) 257-9818 whenever you are ready.