Radon is a radioactive gas. It is colorless, odorless, tasteless, and chemically inert. Unless you test for it, there is no way of telling how much is present.

Radon is formed by the natural radioactive decay of uranium in rock, soil, and water. Naturally existing, low levels of uranium occur widely in earth's crust. It can be found in all 50 states. Once produced, radon moves through the ground to the air above. Some remains below the surface and dissolves in water that collects and flows under the ground's surface.

The Surgeon General has warned that radon is the second leading cause of lung cancer in the United States. There is currently no conclusive data on whether children are at greater risk than adults from radon. No specific subtype of lung cancer is associated with radon exposure.

The EPA states that any radon exposure carries some risk; no level of radon exposure is always safe. However, the EPA recommends homes to be fixed if an occupant's long-term exposure will average 4 picocuries per liter (pCi/L) or higher.

A pCi is a measure of the rate of radioactive decay of radon. One pCi is one trillionth of a Curie, 0.037 disintegrations per second, or 2.22 disintegrations per minute. Therefore, at 4 pCi/L (picocuries per liter, the EPA's recommended action level), there will be approximately 12,672 radioactive disintegrations in one liter of air during a 24-hour period.

Nearly one out of every 15 homes has a radon level the EPA considers to be elevated—4 pCi/L or greater. The U.S. average radon-in-air level in single family homes is 1.3 pCi/L. Because most people spend as much as 90 percent of their time indoors, indoor exposure to radon is an important concern.

No, it is not possible to make a reliable prediction. The only way to determine the level is to test. The EPA and the Surgeon General recommends testing all homes below the third floor for radon.

A map of radon zones has been created to help national, state, and local organizations to target their resources and to implement radon-resistant building codes. However, the map is not intended to be used for determining if a home in a given zone should be tested for radon. Homes with elevated levels of radon have been found in all three zones.

In addition, indoor radon levels vary from building to building. Do not rely on radon test results taken in other buildings in the neighborhood even if it is next door to estimate the radon level in your building.

The National Safety Council's Radon Hotline provides a toll-free number, (800) 767-7236. Through this automated number, callers can order a brochure on radon. It contains information on ordering a low-cost short-term test kit. In addition, users are instructed to call another one of our numbers, (800) 557-2366, if they wish to speak with our information specialists. They are available to assist callers between 9:00 AM to 5:00 PM (Eastern) on business days. They can answer specific questions and mail free, single copies of many radon documents, including the EPA booklet, Home Buyer's and Seller's Guide to Radon.

Multiple copies of the EPA documents can be ordered through the EPA's National Service Center for Environmental Publications (NSCEP), (800) 490-9198 and fax (513) 489-8695. Publication requests can also be mailed, called, or faxed directly to:

U.S. Environmental Protection Agency

National Center for Environmental Publications (NSCEP)

P.O. Box 42419

Cincinnati, OH 42419

Please use the EPA Document Number when ordering from NSCEP. Allow several weeks for delivery.

The EPA also supports operation of other related Hotlines. See the EPA website for information about the following:

Radon FIX-IT Program—assists consumers with elevated radon levels of 4 pCi/L or higher by providing information that will allow them to take the necessary steps toward fixing their home's indoor air quality.

(IAQ INFO)—helps locate information about indoor air pollution.

The National Hispanic Indoor Air Quality Hotline—provides bilingual (Spanish/English) information about indoor air pollutants that consumers may find inside their homes, offices or schools.

Radon is widely believed to be the second leading cause of lung cancer. Therefore, the EPA and the Surgeon General recommend testing for radon in all homes below the third floor.

Radon has been found in homes all over the United States. Any home can have a radon problem. On average, one out of every fifteen U.S. homes has a problem. The only way to know about the radon problem is to go for a test.

Anyone can use a "do-it-yourself" test kit to check their building. The one-use kits are simple to use and are relatively inexpensive. The National Safety Council's Radon Hotline

(800-767-7236) makes test kits available at a low cost to encourage testing.

Radon test kits sometimes are available in hardware stores and other retail outlets. They are also available through the Internet. If you are not doing your own testing, a qualified/state-licensed professional should be hired. Many people find it preferable to hire a professional when testing is being conducted as part of a real estate transaction. Please call Radon Control Services to schedule a radon test. 

Radon levels within a building often change on a day-to-day basis. The highest indoor levels are often found during the heating season. Weather conditions, operation of furnaces and fireplaces, and opening/closing of windows and doors are among the factors that cause these patterns.

Short-term test kits are the quickest way to test. These kits should remain in the building from two to 90 days, depending on the device. Testing must be conducted for at least 48 hours. Some devices must be exposed for a longer time. 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 the year-round average radon level.

Long-term tests remain in your home for more than 90 days. A long-term test gives a reading that is more likely to reflect the building's year-round average radon level than a short-term test. Because of seasonal variations in radon levels, the closer the long-term measurement is to 365 days, the more representative it will be of annual average radon levels.

If time permits (more than 90 days), long-term tests can be used to confirm initial short-term results between 4 pCi/L and 10 pCi/L. When long-term test results are 4 pCi/L or higher, the EPA recommends the problem be corrected.

Two groups of devices are more commonly used for short-term testing.

Passive devices do not need power to function. The group includes alpha-track detectors, charcoal canisters, and charcoal liquid scintillation detectors. Some charcoal technologies are prone to interference by high humidity, so may not be appropriate for use in all buildings. They are sometimes available in drug, hardware, and other stores, the Internet, and through some laboratories. Electrician chamber detectors, another type of short-term test device is usually only available through laboratories. After being used, passive devices are returned to a laboratory for analysis.

Charcoal canisters for short-term use are sold through the National Safety Council's Radon Hotline (800-767-7236). These test kits are designed to be used for two or four days before being returned for analysis by the laboratory that provides it. A return mailer is provided with the kit. See the main radon page for more information.

Active devices require power to function. This group consists of different types of continuous monitors and continuous working level monitors. Some of the active monitors can provide data on the range of variation within the test period. Some are designed to detect and deter interference. However, they usually require operation by trained testers. These tests often cost more than passive testing.

The EPA recommends that testing can be done in the lowest level of the home suitable for occupancy. This typically represents an area where the greatest radon level may occur. Ideally, the test should be conducted in a regularly used room on that level, such as a living room, playroom, den, or bedroom. Avoid testing in a kitchen, bathroom, laundry room, or hallway. High humidity and drafty conditions can bias results from some test devices. Do not disturb the devices while they are sampling. Doing so may alter their results, so they should be placed out-of-the-way.

If the result of an initial short-term measurement is below 4 pCi/L, or 0.02 WL, a follow-up test is not necessary. However, since radon levels change over time, you may want to test again sometime in the future, especially if use patterns change and a lower level of the building becomes occupied or used more often. Renovations, changes in ventilation, earthquakes, settling of the ground beneath the building, and other changes may cause indoor radon exposures to change.

The EPA recommends a follow-up measurement be used to confirm whether radon levels are high enough to warrant mitigation. There are two types of follow-up measurements that may be conducted. The choice depends on the results of the initial test.

An initial measurement result of 10 pCi/L (or 0.05 WL) or greater should be quickly followed by a second short-term test under closed-building conditions. If the average of the initial and second short-term results is equal to or greater than 4 pCi/L (0.02 WL), radon mitigation is recommended. If the average of the short-term test results is less than 4 pCi/L, consider testing again sometime in the future.

If the result of the initial measurement is between 4 pCi/L (or 0.02 WL) and 10 pCi/L (or 0.05 WL), the follow-up test may be made with either a short-term or a long-term method. If a long-term follow-up test result is 4 pCi/L (0.02 WL) or higher, the EPA recommends remedial action. If the long-term follow-up test result is less than 4 pCi/L, consider testing again sometime in the future.

If a short-term follow-up test is done and the result is 4 pCi/L or higher, radon mitigation is recommended. If the average of the initial and follow-up short-term tests is less than 4 pCi/L, consider testing again sometime in the future.

The techniques vary for different foundations and site requirements, but the basic elements are:

Gas Permeable Layer—This layer is placed beneath the slab or flooring system to allow the soil gas to move freely underneath the house. In many cases, the material used is a 4-inch layer of clean gravel.

Plastic Sheeting—Plastic sheeting is placed on top of the gas permeable layer and under the slab to help prevent the soil gas from entering the home. In crawl spaces, the sheeting is placed over the crawlspace floor.

Sealing and Caulking—All openings in the concrete foundation floor are sealed to reduce soil gas entry into the home.

Vent Pipe—A 3- or 4-inch gas-tight or PVC pipe (commonly used for plumbing) runs from the gas permeable layer through the house to the roof to safely vent radon and other soil gasses above the house.

Junction Box—An electrical junction box is installed in case an electric venting fan is needed later.

Radon-resistant techniques are simple and inexpensive. Besides reducing radon levels, they also lower concentrations of other soil gasses and decrease moisture problems. They make a home more energy efficient and can save an annual average of $65 on energy costs.

If a home with a vent system is found to have an elevated radon level, a fan can be added at a low cost. The total cost is much lower than adding the entire system after the building is completed. The average cost to install radon-resistant features in an existing home is $800 to $2,500. The average cost to install radon-resistant features in a new home during construction is $350 to $500 (a 128% to 400% saving).

Talk to your builder about installing a radon-reduction system during major renovations or new construction. Radon-resistant features can be easily and inexpensively installed with common building practices and materials. Many builders already incorporate some of these steps in the construction of their houses to control moisture or increase energy efficiency. RCS can be hired to install a new system during home construction.

Yes, every new home should be tested for radon after occupancy. Test your home even if it has the radon-resistant features. Please call 765-474-1003 to schedule a test today. If you are a do-it-yourself person, test kits are inexpensive and may be purchased at your local hardware store, or call the National Safety Council's Radon Hotline (800-767-7236) to order a test kit.

A radon mitigation system is any system or steps designed to reduce radon concentrations in the indoor air of a building. The EPA recommends that you take action to reduce your home's indoor radon levels if your radon test result is 4 pCi/L or higher.

Radon reduction systems work. In most new homes, use of radon-resistant features will keep radon levels to below 2 pCi/L. Some radon reduction systems can reduce radon levels in your home by up to 99 percent.

Homeowners should consider correcting a radon problem before making final preparations to sell a home. This often provides more time to address the problem and find the most cost-effective solution. In addition, not just the buyer's occupants but the current occupants will also reap the benefit of reduced risk.

The cost of making repairs to reduce radon is influenced by the size and design of your home and other factors. Most homes can be fixed for about the same cost as other common home repairs, like painting or having a new hot water heater installed. The average cost for a contractor to lower radon levels in a home is about $1,200, although this can range from $500 to about $2,500. Your costs may vary depending on the size and design of your home and which radon reduction methods are needed.

Lowering high radon levels requires technical knowledge and special skills. You should use a contractor who is trained to fix radon problems. Many states certify or license radon contractors. Call your state radon office for information about qualified service providers in your state.

Most radon reduction systems include a monitor that'll alert you if the system needs servicing. However, regardless of who fixes the problem, you should test your home afterward to be sure that radon levels have been reduced. This test should be conducted no sooner than 24 hours nor later than 30 days following completion and activation of the mitigation system(s). Potential conflict of interest can be avoided by using an independent tester.

In addition, it's a good idea to retest your home sometime in the future to be sure radon levels remain low. Testing should be done at least every two years or as required or recommended by the state or local authority. Retesting is also recommended if the building undergoes significant alteration.

When the ground produces radon, it can dissolve and accumulate in water from underground sources (called groundwater), such as wells. When water that contains radon is run for showering, washing dishes, cooking, and other uses, radon gas escapes from the water and goes into the air. Some radon also stays in the water.

Radon can be a concern if your drinking water comes from a well that draws from an underground source, though not all water from underground sources contains radon. If you get your water from a public water system that serves 25 or more year-around residents, you will receive an annual water quality report. These water quality reports include information on what is in your water, including radon if it has been tested.

Radon from lakes, rivers, and reservoirs (called surface water) is of much less concern. Most of the radon is released from the water before it enters the distribution system.

Radon can be removed from water by using one of the two methods: aeration treatment or granular activated carbon (GAC) treatment.

Aeration treatments involve bubbling air through the water. This helps to strip radon from the water. An exhaust fan is used to vent the radon outdoors.

GAC treatment filters water through carbon. Radon attaches to the carbon and leaves the water free of radon. GAC filters tend to cost less than aeration devices. However, radioactivity collects on the filter and may cause a handling hazard and require special disposal methods for the filter.