1. Health

Radon and Lung Cancer - What Everyone Should Know


Updated October 31, 2012

Radon is the second leading cause of lung cancer after smoking, and the number one cause of lung cancer in non-smokers. Thankfully, as with smoking, this risk should be entirely preventable through awareness and testing.

What is Radon?

Radon is an odorless, colorless gas that is released from the normal decay of uranium in the soil. Radon can enter homes through cracks in the foundation, floors, and walls, through openings around sump pumps and drains, and through gaps around pipes. Radon may also be present in the water supply in homes that have well water.

Testing for Radon

All homes should be tested for radon, though some regions are more likely to have elevated levels. The Environmental Protection Agency (EPA) has a Radon Zone Map for those interested in looking up the risk in their state. Overall, 1 in 15 homes in the US is estimated to have an elevated radon level, and globally, the World Health Organization estimates that up to 15% of lung cancers worldwide are due to radon exposure.

You can hire someone to test your home for radon, but simple test kits under $20 are available at most hardware stores. These kits are usually placed in the lowest living area in the home and left in place for a few days. The kit is then sent to the manufacturer who returns a report with a radon level.

What Do the Results Mean?

In the United States, a radon level over 4pCi/L (pico curies per liter) is considered abnormal and should be repaired. Repair should also be considered for levels between 2pCi/L and 4pCi/L. In Canada, any level over 2pCi/L is considered abnormal. To understand the significance of these levels, the Environmental Protection Agency has done a risk assessment for radon in homes. A radon level of 4pCi/L is considered five times more likely to result in death than the risk of dying in a car crash.

Radon Mitigation - Fixing Elevated Radon Levels

If radon results are elevated, repairs usually cost between $800 and $2500. Certified contractors can be found through the EPA’s State Radon Contact site. If you are building a new home, check into Radon Resistant Construction.

Helpful Resources

  • National Radon Hotline – 1-800-767-7236
  • National Radon Helpline – 1-800-557-2366
  • National Radon Fix-It Line – 1-800-644-6999


Environmental Protection Agency. Radon. Updated 07/19/2012. http://www.epa.gov/radon/

National Safety Council. Radon. Accessed 07/23/12. http://www.nsc.org/news_resources/Resources/Documents/Radon.pdf

©2014 About.com. All rights reserved.

We comply with the HONcode standard
for trustworthy health
information: verify here.