Radon exposure has no symptoms. You can’t see, smell or taste radon, and breathing it causes no immediate health effects, no irritation and no warning signs (ATSDR, CDC). Because radon has no immediate effects, symptoms such as headaches, fatigue, rashes or nausea are not signs of radon exposure. The danger is long-term: breathing high levels over many years can cause lung cancer (CDC).
So the only way to know whether you’re being exposed is to test your home.
This guide is general information, not medical advice. If you have symptoms or health concerns, see a doctor.
What radon does to your body
Radon gas decays into radioactive particles that can get trapped in your lungs when you breathe. As they decay further, they give off small bursts of energy that can damage lung tissue and, over a lifetime, lead to lung cancer (EPA, A Citizen’s Guide to Radon). Lung cancer is the only cancer proven to be linked to breathing radon. A possible link to leukemia has been suggested, but the evidence isn’t conclusive (National Cancer Institute).
Not everyone exposed to high radon gets lung cancer, and the gap between exposure and disease can be many years (EPA).
How big the risk is
- Radon is the second leading cause of lung cancer in the US, after smoking (CDC).
- EPA and the Surgeon General’s office estimate it causes more than 21,000 lung cancer deaths a year in the US (CDC). The National Cancer Institute gives a range of 15,000 to 22,000 (NCI).
- Worldwide, WHO estimates radon causes 3% to 14% of lung cancers, depending on a country’s radon levels and smoking rates (WHO).
For the risk at specific levels, see radon levels explained.
Lung cancer symptoms
Most people with lung cancer have no symptoms until it is advanced, when it is harder to treat (CDC). When symptoms do appear, they can include (ATSDR):
- a cough that won’t go away;
- coughing up blood;
- difficulty breathing, or wheezing;
- weight loss.
These symptoms have many causes. If you have them, see a doctor whatever your radon level.
Who is most at risk
Your risk from radon depends mostly on how much radon is in your home, how much time you spend there, and whether you smoke or have smoked (EPA). CDC adds (CDC):
- Smokers and former smokers. Radon and smoking together raise the risk much more than either alone. Most radon-related lung cancer deaths are among smokers, though more than 10% are among people who never smoked (NCI).
- People who spend a lot of time in basements or lower floors, where radon is often highest.
- Homes where wood, coal or other fuels are burned, adding particles to the air.
- Children. There isn’t enough data to show whether children face a higher lung cancer risk from radon, but they may receive higher doses than adults at the same level because of their faster breathing and different lung size and shape.
Is there a test for radon exposure?
No. There is no medical screening test that shows how much radon a person has been exposed to (ATSDR). Testing your home is how you measure exposure.
What to do if your home tested high
- Confirm the result with a follow-up test, then fix the home if the level is 4 pCi/L or more. A radon mitigation system can cut levels by up to 99%.
- Tell your doctor your home’s radon results. CDC’s toxic substances agency suggests sharing them with your physician (ATSDR), who can advise you on lung health, including whether lung cancer screening is right for you.
- If you smoke, stopping lowers your risk the most. Call 1-800-QUIT-NOW for free help (CDC).
It’s never too late: lowering your radon level lowers your risk from then on (EPA).