Radon is a radioactive gas. It comes from the natural decay of uranium that is found in nearly all soils. It typically moves up through the ground to the air above and into your home through cracks and other holes in the foundation. Your home traps radon inside, where it can build up.
Any home may have a radon problem. This means new and old homes, well-sealed and drafty homes, and homes with or without basements.
Radon from soil gas is the main cause of radon problems. Sometimes radon enters the home through well water (see “Radon in Water” below).
In a small number of homes, the building materials can give off radon, too. However, building materials rarely cause radon problems by themselves.
Radon Gets In Through:
- Cracks in solid floors
- Construction joints
- Cracks in walls
- Gaps in suspended floors
- Gaps around service pipes
- Cavities inside walls
- The water supply
Nearly 1 out of every 15 homes in the U.S. is estimated to have elevated radon levels. Elevated levels of radon gas have been found in homes in your state.
Contact your state radon office for general information about radon in your area. While radon problems may be more common in some areas, any home may have a problem. The only way to know about your home is to test.
Radon can also be a problem in schools and workplaces. Ask your state radon office about radon problems in schools, daycare and childcare facilities, and workplaces in your area.
Recognizing Radon Poisoning
Radon poisoning can occur where there are high concentrations of radon gas. This typically occurs in areas with poor ventilation, such as underground mines, crawl spaces, or basements in homes or buildings.
Scientists first identified that underground uranium miners were being exposed to radon and dying of lung cancer at very high rates.
Since radon originates in the soil through its decaying process, it also gives off tiny radioactive particles that can be inhaled into the lungs.
These radioactive particles can then cause damage to the lungs, possibly resulting in lung cancer.
Radon poisoning symptoms resemble those of lung cancer: a persistent cough that doesn’t get better, difficulty breathing, chest pains, the coughing up of blood, wheezing, hoarseness and recurring respiratory infections such as pneumonia or bronchitis.
In some cases, long-term exposure to radon can lead to lung cancer, the only cancer proven to be associated with inhaling radon — between 15,000 and 22,000 lung cancer deaths occur in the U.S. each year according to the National Cancer Institute.
Therefore, it is extremely important that you seek medical help as soon as possible if you begin to experience these warning symptoms.
How to Test Your Home for Radon
You can’t see radon, but it’s not hard to find out if you have a radon problem in your home. All you need to do is test for radon. Testing is easy and should only take a few minutes of your time.
The amount of radon in the air is measured in “picocuries per liter of air,” or “pCi/L.” There are many kinds of low-cost “do-it-yourself” radon test kits you can get through the mail and in some hardware stores and other retail outlets.
If you prefer, or if you are buying or selling a home, you can hire a qualified tester to do the testing for you. You should first contact your state radon office about obtaining a list of qualified testers.
You can also contact a private radon proficiency program for lists of privately certified radon professionals serving your area.
There are Two General Ways to Test for Radon: Testing is easy and should only take a few minutes of your time.
Short-Term Testing for Radon
The quickest way to test is with short-term tests. Short-term tests remain in your home for two days to 90 days, depending on the device. “Charcoal canisters,” “alpha track,” “electretion chamber,” “continuous monitors,” and “charcoal liquid scintillation” detectors are most commonly used for short-term testing. Because radon levels tend to vary from day to day and season to season, a short-term test is less likely than a long-term test to tell you your year-round average radon level. If you need results quickly, however, a short-term test followed by a second short-term test may be used to decide whether to fix your home (see Home Sales).
Long-Term Testing for Radon
Long-term tests remain in your home for more than 90 days. “Alpha track” and “electret” detectors are commonly used for this type of testing.
A long-term test will give you a reading that is more likely to tell you your home’s year-round average radon level than a short-term test.
EPA Recommends the Following Testing Steps:
Step 1. Take a short-term test. If your result is 4 pCi/L or higher, take a follow-up test (Step 2) to be sure.
Step 2. Follow up with either a long-term test or a second short-term test:
For a better understanding of your year-round average radon level, take a long-term test.
If you need results quickly, take a second short-term test.
The higher your initial short-term test result, the more certain you can be that you should take a short-term rather than a long-term follow up test.
If your first short-term test result is more than twice EPA’s 4 pCi/L action level, you should take a second short-term test immediately.
Step 3. If you followed up with a long-term test: Fix your home if your long-term test result is 4 pCi/L or more.
If you followed up with a second short-term test: The higher your short-term results, the more certain you can be that you should fix your home.
Consider fixing your home if the average of your first and second test is 4 pCi/L or higher.
How To Use a Radon Test Kit
Follow the instructions that come with your test kit. If you are doing a short-term test, close your windows and outside doors and keep them closed as much as possible during the test.
Heating and air-conditioning system fans that re-circulate air may be operated. Do not operate fans or other machines which bring in air from outside.
Fans that are part of a radon-reduction system or small exhaust fans operating only for short periods of time may run during the test.
If you are doing a short-term test lasting just 2 or 3 days, be sure to close your windows and outside doors at least 12 hours before beginning the test, too.
You should not conduct short-term tests lasting just 2 or 3 days during unusually severe storms or periods of unusually high winds.
The test kit should be placed in the lowest lived-in level of the home (for example, the basement if it is frequently used, otherwise the first floor).
It should be put in a room that is used regularly (like a living room, playroom, den or bedroom) but not your kitchen or bathroom.
Place the kit at least 20 inches above the floor in a location where it won’t be disturbed – away from drafts, high heat, high humidity, and exterior walls.
Leave the kit in place for as long as the package says. Once you’ve finished the test, reseal the package and send it to the lab specified on the package right away for analysis. You should receive your test results within a few weeks.
What Your Test Results for Radon Mean
Test your home now and save your results. If you find high radon levels, fix your home before you decide to sell it.
The average indoor radon level is estimated to be about 1.3 pCi/L, and about 0.4 pCi/L of radon is normally found in the outside air.
The U.S. Congress has set a long-term goal that indoor radon levels be no more than outdoor levels. While this goal is not yet technologically achievable in all cases, most homes today can be reduced to 2 pCi/L or below.
Sometimes short-term tests are less definitive about whether or not your home is above 4 pCi/L. This can happen when your results are close to 4 pCi/L.
For example, if the average of your two short-term test results is 4.1 pCi/L, there is about a 50% chance that your year-round average is somewhat below 4 pCi/L.
However, EPA believes that any radon exposure carries some risk – no level of radon is safe. Even radon levels below 4 pCi/L pose some risk, and you can reduce your risk of lung cancer by lowering your radon level.
If your living patterns change and you begin occupying a lower level of your home (such as a basement) you should retest your home on that level.
Even if your test result is below 4 pCi/L, you may want to test again sometime in the future.
The Risk of Living With Radon
Scientists are more certain about radon risks than from most other cancer-causing substances.
Radon gas decays into radioactive particles that can get trapped in your lungs when you breathe. As they break down further, these particles release small bursts of energy.
This can damage lung tissue and lead to lung cancer over the course of your lifetime. Not everyone exposed to elevated levels of radon will develop lung cancer.
And the amount of time between exposure and the onset of the disease may be many years.
Like other environmental pollutants, there is some uncertainty about the magnitude of radon health risks. However, we know more about radon risks than risks from most other cancer-causing substances.
This is because estimates of radon risks are based on studies of cancer in humans (underground miners).
Children have been reported to have greater risk than adults of certain types of cancer from radiation, but there are currently no conclusive data on whether children are at greater risk than adults from radon.
Your chances of getting lung cancer from radon depend mostly on:
- How much radon is in your home
- The amount of time you spend in your home
- Whether you are a smoker or have ever smoked