Radon Testing
by Illinois Licensed Radon Professionals

& Answers


Note:  Above answers have been provided by EPA (US Environment Protection Agency), IEMA (Illinois Emergency Management Agency)
and by the research team of Regency Consulting Services, Inc.     Please visit the EPA website for additional information about radon.    < EPA >
E-mail us your questions about radon  – we will be
happy to do some research and find the appropriate
answers for you.

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Tel:   630-225-7997
Fax: 630-839-4988

Frequent Questions about RADON


Q: How does radon get into your home?

A: Any home may have a radon problem.
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
Radon from soil gas is the main cause of radon problems. Sometimes radon enters the home through well water". In a small number of
homes, the building materials can give off radon, too. However, building materials rarely cause radon problems by themselves.

Q: What are the health effects from exposure to radon?

A: There are no immediate symptoms from exposures to radon. Based on an updated Assessment of Risk for Radon in Homes, radon in
indoor air is estimated to cause about 21,000 lung cancer deaths each year in the United States. Smokers are at higher risk of developing
Radon-induced lung cancer. Lung cancer is the only health effect which has been definitively linked with radon exposure. Lung cancer
would usually occur years (5-25) after exposure. There is no evidence that other respiratory diseases, such as asthma, are caused by
radon exposure and there is no evidence that children are at any greater risk of radon induced lung cancer than adults.

Q: Where does radon come from?

A: Radon-222 is the decay product of radium-226. Radon-222 and its parent, radium-226, are part of the long decay chain for uranium-
238. Since uranium is essentially ubiquitous (being or seeming to be everywhere at the same time) in the earth's crust, radium-226 and
radon-222 are present in almost all rock and all soil and water.
The amount of radon in the soil depends on soil chemistry, which varies from one house to the next. Radon levels in the soil range from a
few hundred to several thousands of pCi/L (pico Curries per Liter). The amount of radon that escapes from the soil to enter the house
depends on the weather, soil porosity, soil moisture, and the suction within the house.

Q: Does foundation type affect radon entry?

Any home can potentially have a radon problem. All conventional house construction types, including homes with basements or crawl
spaces with gravel, dirt or concrete slabs as well as slab-on-grade foundations have been found to have high radon levels exceeding the
action level of 4 pCi/L. Radon can enter a home due to negative interior air pressure, regardless of the foundation type. When building a
house with a slab-on-grade foundation, the builder still excavates the ground to construct the foundation footings, disturbing the natural
protection provided by the composition of clay and dirt. Slab foundations built on grade can have just as many openings to allow radon to
enter as do basements. The radon levels in a home built on grade may have reduced levels, - but why take the chance?

Q: Are we sure that radon is a health risk?

A: EPA already has a wealth of scientific data on the relationship between radon exposure and the development of lung cancer. The
scientific experts agree that the occupational miner data is a very solid base from which to estimate risk of lung cancer deaths annually.
While residential radon epidemiology studies will improve what we know about radon, they will not supersede the occupational data. Health
authorities like the Centers for Disease Control (CDC), the Surgeon General , the American Lung Association, the American Medical
Association, and others agree that we know enough now to recommend radon testing and to encourage public action when levels are
above 4 pCi/L. The most comprehensive of these efforts has been the National Academy of Science's Biological Effects of Ionizing
Radiation (BEIR VI) Report (see This report reinforces that radon is the second-leading cause of lung
cancer and is a serious public health problem. As in the case of cigarette smoking, it would probably take many years and rigorous
scientific research to produce the composite data needed to make an even more definitive conclusion.
What is Radon?

Q: What is the Definition of Radon?

A: Radon is a gaseous radioactive element having the symbol Rn, the atomic number 86, an atomic weight of 222, a melting point of -71ºC,
a boiling point of -62ºC, and (depending on the source, there are between 20 and 25 isotopes of radon - 20 cited in the chemical
summary, 25 listed in the table of isotopes); it is an extremely toxic, colorless gas; it can be condensed to a transparent liquid and to an
opaque, glowing solid; it is derived from the radioactive decay of radium and is used in cancer treatment, as a tracer in leak detection, and
in radiography. (From the word radium, the substance from which it is derived.)
Sources: Condensed Chemical Dictionary, and Handbook of Chemistry and Physics, 69th ed., CRC Press, Boca Raton, FL, 1988.

Q: Should I test the soil for radon before building?

Soil testing for radon is not recommended for determining whether a house should be built radon-resistant.  Although soil testing can be
done, it cannot rule out the possibility that radon could be a problem in the house you build on a lot.  Even if soil testing reveals low levels
of radon gas in the soil, the amount of radon that may enter the finished house cannot be accurately predicted because one cannot
predict the impact that the site preparation will have on introducing new radon pathways or the extent to which a vacuum will be produced
by the house.  Furthermore, the cost of a single soil test for radon ranges from $70 to $150, and at least 4 to 8 tests could be required to
accurately characterize the radon in the soil at a single building site.  Therefore, the cost to perform the soil testing is very high when
compared with installing the passive radon system in high radon potential areas.

Q: How do we know radon is a carcinogen?

A: The World Health Organization (WHO), the National Academy of Sciences, the US Department of Health and Human Services, as well as
EPA, have classified radon as a known human carcinogen, because of the wealth of biological and epidemiological evidence and data
showing the connection between exposure to radon and lung cancer in humans.
There have been many studies conducted by many different organizations in many nations around the world to examine the relationship of
radon exposure and human lung cancer. The largest and most recent of these was an international study, led by the National Cancer
Institute (NCI), which examined the data on 68,000 underground miners who were exposed to a wide range of radon levels. The studies of
miners are very useful because the subjects are humans, not rats, as in many cancer research studies. These miners are dying of lung
cancer at 5 times the rate expected for the general population. Over many years scientists around the world have conducted exhaustive
research to verify the cause-effect relationship between radon exposure and the observed increased lung cancer deaths in these miners
and to eliminate other possible causes.
In addition, there is an overlap between radon exposures received by miners who got lung cancer and the exposures people would receive
over their lifetime in a home at EPA's action level of 4 pCi/L (pico Curries per Liter), i.e., the lung cancer risk in miners has been
documented at exposure levels comparable to those which occur in homes/residences.


Q: Are their guide lines for radon testing during a real estate transaction?

A: Because of the unique nature of real estate transactions, involving multiple parties and financial interests, EPA (Environmental
Protection Agency) designed special protocols for radon testing in real estate transactions. IEMA (Illinois Emergency Management Agency)
has adapted these protocols to conform with this radon regulations.

Q:Is their a law to test for radon during a real estate transaction?

A: No – Only a Recommendation! IEMA strongly recommends ALL homebuyers have an indoor radon test performed prior to purchase a
home and have it mitigated if elevated levels are found.

Q: Who should perform the radon test during a real estate transaction?

A: It is in the best interest of the buyer and seller to rely ONLY on a radon measurement performed by a licensed measurement
professional or technician.

Q: What kind of testing equipment should be used for a real estate transaction radon test?

A: Only EPA & IEMA approved Radon Detectors such as CRM’s (Continuous Radon Monitor) are to be used for this purpose.

Q What about “Electronic Radon Detectors” sold over the counter or on line?

A:  According to Section 422.140, Radon Testing Monitors require to be calibrated in a radon chamber, approved by  IEMA (The Agency)
before being placed into service and the CR monitors shall be programmed to run continuously, recording periodically (hourly or more
frequently) the radon concentration for at least 48 hours.

Q: Where can I find IEMA’s Guidelines for Real Estate Transactions?

A: Click on this link to find Radon Testing Guidelines!

Q: How often should I test/retest my home for radon?

A: The  general guidance from EPA,  “A Citizen's Guide to Radon” suggests to test:
  • 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.

  • If you are buying or selling a home  (EPA’s Home Buyer's and Seller's Guide to Radon)

  • If you are thinking of selling your home and you have already tested your home for radon,  review the Radon Testing Checklist to
    make sure that the test was done correctly.  If so, provide your test results to the buyer.

Q: What if the home was previously tested?

A buyer should ask for a new test if the state or local government requires disclosure of radon information to the buyers, especially if:
  • The Radon Testing Checklist items were not met;
  • The last test is not recent, e.g., within two years;
  • The home was renovated or altered since the last test
  • The buyer plans to live in a lower level of the house than was tested, such as a basement suitable for occupancy but not currently
    lived in.

Radon in Granite:

Q: Does the EPA believe that radon is in granite counters?  

A: There is some evidence that some granite used in countertops may contain varying concentrations of uranium which produces radon.

Q: Are the levels dangerous to humans or animals?  

A: There is too little information and too many variables to generalize about the potential or actual risk.

Q: Has the EPA done studies on radon in granite counters?  

A: No

Q: Does the EPA have plans to conduct a study on radon in granite countertops?  

A: Not at this point in time.