Feb 2, 2015: Is RADON poisonous?

Recently I was interviewed by a television newscaster regarding radon because a couple had become concerned when they were told their dwelling contained a “high amount of radon”.  Everyone has questions about radon. 

As unanium-238 (naturally occurs in earth’s crust) decays, it forms radon, a gas which “leaks” out of the earth’s crust into the atmosphere. The problem occurs when radon gas gets trapped in buildings: basements, rooms, etc., where it can’t vent or slowly vents into the atmosphere.  Radon gas, with its short half-live (~3.8 days), and because it is a noble/inert gas is not a poison itself.  There are no immediate signs/symptoms from radon exposure.  It cannot be seen, felt, smelled or tasted.  It is a heavy gas and tends to accumulate in basements and low areas.  Because of the natural radioactive element decay, radon eventually forms radioactive “daughter products” such as polonium 210 (138 day half-live) and 218 (3 minute half-live), and lead 214 (stable nuclide).  These latter decay products have much longer half-lives and are potent alpha particle (helium nucleus) emitters.  This means a person’s lung alveolar cells get bombarded with alpha particles.  Over a life-time, the amount of radon gas trapped in a dwelling where one resides as well as the total amount of radon a person breaths determines their chance of developing lung cancer. Significant exposure to radon over years increases the chance of lung cancer developing.

January is National RADON Action Month.   Check out www.epa.gov/radon for more information, and please check your homes, and encourage your patients to check their homes.  Many more answers to how to remediate a home are available through this link.

Radon Risk If You've Never Smoked:


Radon Level

If 1,000 people who never smoked were exposed to this level over a lifetime*...

The risk of cancer from radon exposure compares to**...


20 pCi/L

About 36 people could get lung cancer

35 times the risk of drowning

Fix your home

10 pCi/L

About 18 people could get lung cancer

20 times the risk of dying in a home fire

Fix your home

8 pCi/L

About 15 people could get lung cancer

4 times the risk of dying in a fall

Fix your home

4 pCi/L

About 7 people could get lung cancer

The risk of dying in a car crash

Fix your home

2 pCi/L

About 4 people could get lung cancer

The risk of dying from poison

Consider fixing between 2 and 4 pCi/L

1.3 pCi/L

About 2 people could get lung cancer

(Average indoor radon level)

(Reducing radon levels below 2 pCi/L is difficult.)

0.4 pCi/L


(Average outdoor radon level)

Note: If you are a former smoker, your risk may be higher.
* Lifetime risk of lung cancer deaths from EPA Assessment of Risks from Radon in Homes (EPA 402-R-03-003).
** Comparison data calculated using the Centers for Disease Control and Prevention's 1999-2001 National Center for Injury Prevention and Control Reports.


This question prepared by:  John Benitez, MD, MPH  Medical Toxicologist


I am interested in any questions you would like answered in the Question of the Week.  Please email me with any suggestion at donna.seger@vanderbilt.edu


Donna Seger, MD

Medical Director

Tennessee Poison Center


Poison Help Hotline: 1-800-222-1222