Radon Informationhow_radon_enters

Radon is a colorless, odorless, radioactive gas that has been shown to be the second leading cause of lung cancer in the United States, after tobacco smoking. It occurs naturally in the soils in some areas of the country, including much of Colorado. If your home has high levels of Radon (above 4.0 pCi/l), the EPA recommends mitigation. Radon mitigation is generally a straightforward process involving the installing ventilation equipment in the home.

Frequently-Asked Radon Questions: Environmental Protection Agency 

  • How does radon get into your home? 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 over time. Any home can 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, as well, but this scenario is incredibly rare.
  • What is the average level of radon found in homes in the U.S.? Based on a national residential radon survey completed in 1991, the average indoor radon level is about 1.3 picocuries per liter (pCi/L) in the United States. The average outdoor level is about 0.4 pCi/L.
  • What are the health effects from exposure to radon?
  • There are no immediate symptoms from exposures to radon. Based on an updated Assessment of Risk for Radon in Homes (see www.epa.gov/radon/risk_assessment.html), 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. Symptoms are not immediate, and lung cancer typically develops  years after exposure. There is little 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.
  • Where does radon come from? 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, soil, and water. The amount of radon in the soil depends on soil chemistry, which varies from one location 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.
  • Are we sure that radon is a health risk? The 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 www.epa.gov/radon/beirvi.html). 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.
  • Should I be concerned about the accuracy of radon test kits? While it is true that any given radon testing device or instrument will have an associated variability in precision and accuracy, the EPA’s measurement recommendations raise the probability that high-contamination homes will be identified and fixed. For example, the EPA recommends using multiple short-term tests to reduce errors and increase the likelihood that the correct mitigation decision is made. In addition, the EPA recommends testing every two years or following a significant renovation. Consumers are also advised to seek the advice of state public health officials and qualified measurement professionals if they require further guidance. Accuracy and reliability reside in the overall measurement approach, designed to maximize the amount of public risk reduction as well as the need for test devices that are easy to obtain, cheap to buy, and simple to administer.
  • How do I get a radon test kit? Are they free? Radon test kits are available from several sources. Free test kits are sometimes available from local or county health departments, or from state radon programs. The National Radon Program Services at Kansas State University has test kits available to purchase online at www.sosradon.org or call 1-800-SOS-RADON (1-800-767-7236). Test kits are also available from some local or state American Lung Associations (www.lungusa.org) and some home improvement stores.  To learn more about the availability of test kits in your area, or to find a qualified testing or mitigation contractor, contact your state radon office (go to www.epa.gov/radon/whereyoulive.html and click on your state for a list of contacts) or contact either of the national private radon programs (see www.epa.gov/radon/radontest.html for contact information).
  • What about radon and radioactivity in granite countertops? Does the EPA believe there is a danger of radon gas or associated radiation being emitted from granite countertops?  It is possible for any granite sample to contain varying concentrations of uranium and other naturally occurring radioactive elements. These elements can emit radiation and produce radon gas, a source of alpha and beta particles and gamma rays. Some granite used for countertops may contribute variably to indoor radon levels. Some types of granite may emit gamma radiation above typical background levels. However, at this time the EPA believes that the existing data is insufficient to conclude that the types of granite commonly used in countertops are significantly increasing indoor radon levels. While radiation levels are not typically high, measurement of specific samples may reveal higher than expected levels on a case-by-case basis. Granite is a naturally occurring igneous rock, meaning that it was formed by the cooling of molten rock. It is quarried and processed to produce commercial products such as countertops.
  • What advice does the EPA have about radon for consumers who have granite countertops? The EPA believes the principal source of radon in homes is from the soil in contact with basement floors and walls. To reduce the radon risk, you should first test the air in your home to determine the radon level. There are many do-it-yourself radon test kits available through retail outlets and online, starting at about $25. While natural rocks such as granite may emit radiation and radon gas, the levels attributable to such sources are not typically high.  If your home has a radon level of 4 picocuries per liter (pCi/L) of air or more, you should take steps to fix your home and reduce the radon level. Contact your state radon office (www.epa.gov/radon/whereyoulive.html) for assistance. Hire a qualified radon professional (www.epa.gov/radon/radontest.html) to fix or mitigate your home. The key to reducing your risk of lung cancer from radon is to test your home and mitigate when necessary. A specially-trained and qualified radiation professional may be equipped to test for other radon sources (such as granite or diffusion from drinking water) when diagnosing the nature and source of your home’s radon problem.  Learn more about radon, visit www.epa.gov/radon or read A Citizen’s Guide to Radon at www.epa.gov/radon/pubs/citguide.html.
  • Can I test my granite countertops for radiation or radon? At this time, a generally accepted radiation testing protocol for countertops does not exist, and neither imported nor domestic granite products require radiation testing. Radiation concentrations can only be measured using sophisticated portable instruments, or with laboratory equipment. These instruments and equipment require a knowledgeable and trained user and proper instrument calibration. For information about local radiation experts, the Conference of Radiation Control Program Directors (CRCPD) maintains a web page where you can find contact information for each state’s radiation protection program. Please visit their webpage, www.crcpd.org/Map/map.asp, to find information for your state.  Although not specifically designed or intended for measuring radon emissions from countertops, do-it-yourself test kits are available through retail outlets and on-line, starting at about $25. If you are concerned about the radon level in your home, purchase a test kit and use as instructed. To learn more, visit www.epa.gov/radon or read A Citizen’s Guide to radon at www.epa.gov/radon/pubs/citguide.html.
  • Are the levels of radon gas and radiation emissions from granite countertops dangerous to humans or animals? While radon gas and radiation emission levels attributable to granite are not typically high, there are simply too many variables to generalize about the potential health risks inside a particular home that has granite countertops. It is prudent to limit your family’s exposure to radon whenever possible. Commonly employed mitigation techniques can reduce the radon level coming from soil beneath your home to 2 pCi/L or less in most homes. At EPA’s action level of 4 pCi/L, a smoker’s risk of lung cancer is about five times the risk of dying in an auto accident, and if you’ve never smoked equal to the risk of dying in an auto accident. The U.S. Surgeon General and EPA strongly recommend that all homes be tested for radon.
  • Has the EPA done studies on radon gas and radiation emissions from granite countertops? We are aware of a few studies that have conducted limited research on radon in granite countertops. The EPA will continue to review this research. However, there are many studies proving the link between radon in indoor air and lung cancer, including the EPA’s 2003 risk assessment – www.epa.gov/radon/risk_assessment.html.
  • Does the EPA have plans to conduct a study of granite countertops? The EPA will continue to monitor and analyze the evolving research on radiation and granite countertops and will update its recommendations as appropriate. There are currently no regulations concerning granite countertops radon gas or radiation emissions.

Radon Remediation

In most cases, a system with vent pipes and fans is used to reduce radon. These “sub-slab depressurization” systems do not require major changes to your home. Similar systems can also be installed in homes with crawl spaces. These systems prevent radon gas from entering the home from below the concrete floor and from outside the foundation. Radon mitigation contractors may use other methods that may also work in your home. The right system depends on the design of your home and other factors.

Radon and Home Renovations

If you are planning any major renovations, such as converting an unfinished basement area into living space, it is especially important to test the area for radon before you begin. If your test results indicate an elevated radon level, radon-resistant techniques can be inexpensively included as part of the renovation. Major renovations can change the level of radon in any home. Test again after the work is completed. You should also test your home again after it is fixed to be sure that radon levels have been reduced. 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. In addition, it is a good idea to retest your home sometime in the future to be sure radon levels remain low.

Selecting a Radon-Reduction (Mitigation) Contractor

Select a qualified radon-reduction contractor to reduce the radon levels in your home. Any mitigation measures taken or systems installed in your home must conform to your state’s regulations. The EPA recommends that the mitigation contractor review the radon measurement results before beginning and radon-reduction work. Test again after the radon mitigation work has been completed to confirm that previously elevated levels have been reduced.

What Can a Qualified Radon-Reduction Contractor Do for You?

A qualified radon reduction (mitigation) contractor should be able to:

  • Review testing guidelines and measurement results, and determine if additional measurements are needed
  • Evaluate the radon problem and provide you with a detailed, written proposal on how radon levels will be lowered
  • Design a radon-reduction system
  • Install the system according to EPA standards, or state or local codes
  • Make sure the finished system effectively reduces radon levels to acceptable levels

Choose a radon mitigation contractor to fix your radon problem just as you would for any other home repair. You may want to get more than one estimate, ask for and check their references. Make sure the person you hire is qualified to install a mitigation system. Some states regulate or certify radon mitigation services providers. Be aware that a potential conflict of interest exists if the same person or firm performs the testing and installs the mitigation system. Some states may require the homeowner to sign a waiver in such cases. Contact your state radon office for more information.