Radon and Lung Cancer: What You Need to Know
CancerLung Cancer

Radon in Your Home Can Cause Lung Cancer

Radon in Your Home Can Cause Lung Cancer
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Updated on June 19, 2025
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When you think about pollution, you may only consider what you’re exposed to outdoors. But indoor air quality in your home matters, too, and it can be majorly affected by the presence of a radioactive gas called radon. At high concentrations, radon increases the risk of lung cancer — even if you don’t smoke.

For that reason, every home should take advantage of radon testing, which is easy, inexpensive, and lifesaving.

What Is Radon, and Where Can It Be Found in My Home?

Radon is an odorless, colorless, and naturally occurring radioactive gas. It is inhaled into the lungs, where it can damage the DNA, potentially increasing cancer risk, says Douglas Arenberg, MD, a professor in the pulmonary diseases and critical care departments at the University of Michigan Health System in Ann Arbor.

Radon forms when uranium, thorium, or radium breaks down in water, rocks, and soil, releasing radon gas into the dirt beneath your home.

 Radon can enter your home through cracks and holes in the foundation, through well water, and via building materials.

It’s common: About 1 in every 15 homes has what’s considered an elevated radon level.

 The gas is odorless and invisible, and it causes no immediate symptoms, so the only way to know if your home is affected is by testing your individual residence.

How Does Radon Cause Lung Cancer?

Chronic exposure to radon gas increases the risk of developing lung cancer. In the United States, an estimated 21,000 people die from radon-related lung cancer every year (compared with 160,000 lung cancer deaths from smoking).

 Radon is the second leading cause of lung cancer, and it’s the leading cause of lung cancer in nonsmokers.

 People who smoke or used to smoke have an even greater chance of developing lung cancer if they are exposed to radon.
“Lung cancer risk from radon exposure occurs over many years of high-level exposure,” Dr. Arenberg says. Breathing in radon traps these radioactive particles in your lungs, which can eventually lead to lung cancer.

 Your risk is then increased depending on your exposure level (if you spend a lot of time in the areas of your home with higher radon levels), your status as a smoker, and your exposure to other in-home pollutants, like a wood-burning stove or fireplace.

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Home Testing for Radon: The Basement Is Key

Because radon can be found outdoors in low levels, everyone is exposed to it at some point.

 But it’s much more dangerous inside a home, where the gas is more confined and therefore concentrated at significantly higher levels.
An at-home kit (available at most hardware stores) that is labeled as “meets EPA requirements” can be used to test for radon in your home.

 You can start with short-term (usually two-day) radon testing with a home kit; the sample you collect is sent for analysis, with results mailed to you within a few weeks.

You can also do long-term testing, which gives you a more accurate picture of the radon levels in your home — the test measures air quality over a period of about 90 days.

 Since radon levels can fluctuate frequently, it’s usually best to do a long-term test. Long-term tests can also be performed with a home kit.

“It is important to note that for people who do not spend any time in their basement, it may not be necessary to measure your radon level in the basement,” Arenberg says. “Radon is not a problem on upper levels of houses, given the airflow which naturally reduces exposure to radon. I recommend people check the levels only if they have a finished basement or otherwise spend a lot of time in their basement.”

When testing, carefully follow all instructions on the kit.

 Both short- and long-term tests can be done simultaneously. Checking water for radon requires a separate test. Consult your local health department for information on testing your water, or contact a radon specialist.

How to Reduce Radon Levels in Your Home

If the radon levels in your home exceed 4 picocuries per liter, you should take steps to reduce the radon level as soon as possible.

Over time, radon will disappear due to radioactive decay. However, “anyone with elevated radon levels should take the time and spend the money to get the problem fixed,” Arenberg says. He stresses that you should not panic if you do have high levels of radon in your basement because “it’s very easy to remedy this.”

You can install a removal system that allows radon gas from beneath the home to be immediately vented outside. Radon removal can eliminate up to 99 percent of radon from the home.

 These devices, called soil-suction radon reduction systems, should always be installed and supervised by a certified radon mitigation specialist or radon remediation service.

You or the radon remediation specialist can also seal off any cracks in your home — in the floors, foundation, or walls — to keep radon gas from seeping through the cracks and into the air you breathe indoors.

Retesting should be done at regular intervals to ensure that the radon mitigation has been successful.

The Takeaway

  • Radon is an invisible and odorless radioactive gas that can cause serious health issues, such as lung cancer.
  • Although you can be exposed to radon anywhere, there’s a greater threat to your health if radon is allowed to build up inside the home.
  • If you’re concerned that your house has a high level of radon, consider buying a radon test kit from a local hardware store.
  • If a high level of radon is found in your home, a radon mitigation or remediation specialist can install a radon reduction system to remove up to 99 percent of the gas.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Radon. American Lung Association. May 28, 2025.
  2. Radon and Your Health. Centers for Disease Control and Prevention. February 16, 2024.
  3. How does radon get into your home? Environmental Protection Agency. March 27, 2025.
  4. Home Buyer’s and Seller’s Guide to Radon. Environmental Protection Agency. March 2024.
  5. Health Risk of Radon. Environmental Protection Agency. February 27, 2025.
  6. Find a Radon Test Kit or Measurement and Mitigation Professional. Environmental Protection Agency. January 23, 2025.
  7. Consumer’s Guide to Radon Reduction How to Fix Your Home. Environmental Protection Agency. 2016.
  8. What Is EPA's Action Level for Radon and What Does it Mean? Environmental Protection Agency. December 2, 2024.
  9. How much can a radon mitigation system cost? Environmental Protection Agency. November 15, 2024.
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