Health Effects of Radon

What is Radon?

Radon is a gas that is created in the soils where uranium and radium are found. These elements can be found everywhere in the world, therefore any building has the potential for elevated levels of radon. The more uranium found in the soil, the higher the potential for elevated radon levels within a building constructed above this soil. It is not a question of, Is there radon? but rather, How much radon is there?

Radon primarily comes from natural deposits of uranium in the soil. It is not because of a man-made landfill or other suspicious sources. Uranium breaks down to radium, which in turn decays into radon gas.

Radon is an inert gas, which means that it does not react or combine with the elements in the ground. Because of this, radon gas can move up through the soil into the atmosphere, where it is easily diluted and presents little concern. However, when it enters a building constructed on top of this soil, it can build up and become a health concern.

You cannot see or smell radon. There is no way that your body can sense the presence of radon, yet it can have a detrimental effect on the inhabitants by increasing their likelihood of developing lung cancer.

How Radon is Drawn into a Building?

Buildings are typically at a lower pressure than the surrounding air and soil. This causes radon and other soil gases to be drawn into the building.

There are several reasons why this occurs. One cause is the effect that exhaust fans have when removing air from a building. When air is exhausted, outside air enters the building to replace it. Much of this replacement air comes in from the underlying soil.

When interior temperatures are higher than outside temperatures, thermal effects occur inside of the building. Just as warm air causes a balloon to rise because the surrounding air is cool, warm air rises within a building and is displaced by cold, dense outside air. Some of the outside air, which is displacing and replacing the interior air, comes from the soil.

Whenever air enters a building from underneath, radon will most likely come in as well if radon is present in the underlying soil.

The forces that draw radon into a structure vary, which in turn effects the entry rate of radon. Measurement devices that average radon levels over long periods of time provide a better indication of the amount of exposure to radon.

The minimum duration of any test, the results of which could be used as a basis for determining the need for remediation, is 48 hours.

Radon also varies from season to season as a function of climate and the use of the home by occupants (open windows-closed windows). It would be ideal if a year-long test could be conducted, however, such timing would be unrealistic for the purpose of a real estate transaction.

Short-term tests are utilized to determine the potential of a home for having elevated levels of radon, independently of how the house is operated. The tests involve closing all windows and doors, except for normal exit and entry, and testing on the lowest occupiable location in the home. This technique has become the method for testing homes during real estate transactions.

Why is Radon a Concern?

Once radon enters a building it is easily dispersed through the air. The radioactive decay process that leads to the creation of radon does not stop. This causes the radon to decay into several radioactive elements called radon decay products. These decay products are made up of different forms of polonium, lead and bismuth.

Unlike radon, which is a gas, the radon decay products produced from radon are solid particles. These particles become suspended in the air when they are formed from the decaying radon gas. These particles are extremely small and cannot be seen.

Because they are extremely small particles, radon decay products are easily inhaled and can attach to lung tissue. They have very short “half-lives” which means that they will decay relatively quickly after they are formed. In fact, if they are inhaled, they will decay in the lungs before the lungs have an opportunity to clean themselves.
It is the radon decay products that actually present the health risk associated with radon gas.
 

Radon is a Lung Cancer Causing Gas

When radon decay products are inhaled they will stick to sensitive lung tissue. Being short-lived, they will break down while they are in the lungs, thereby exposing the lung tissue to radiation.

When radon decay products decay, they release alpha, beta and gamma radiation. It is actually the alpha radiation (in the form of particles) from the two radon decay products - polonium 218 and polonium 214 - that are the most hazardous.

The alpha particles, that come from the decay of radon decay products, will impact the sensitive lung tissue. In most cases they will kill the lung tissue cell, which can be replaced by the body. However, the alpha particles can impact the DNA, or create a chemical reaction that will affect the DNA. When this occurs the cell can become mutated.

This is the mechanism by which prolonged exposure to radon and radon decay products can increase the potential of lung cancer.

What Happens When Radon Decay Products Are Inhaled?

When radon decay products are inhaled they stick to sensitive lung tissue. Being short-lived, they will break down while they are in the lungs. This exposes the lung tissue to radiation.

If the alpha particle which is released hits a live cell, and within the cell it hits the nucleus, and within the nucleus it hits the DNA, and within the DNA it hits and damages the cancer suppressant gene and increased risk for contracting lung cancer can exist. In addition to the alpha particle causing, the alpha particle can also cause ionization of material around the DNA that can also damage it (shown on right of DNA strand).

This is the mechanism that radon (and more specifically the radon decay products) can lead to an increased risk of lung cancer.

Probability of Radon Induced Lung Cancer

What is the probability of this happening? It is based on how much you are exposed to and for how long. Being exposed to radon does not mean that you will contract lung cancer. To develop lung cancer from radon the radiation released from its decay has to strike a lung cell and within that lung cell it has to strike a specific location.

Since the radiation is released in a random manner, the potential for lung cancer increases with exposure, whether that be exposure to a small amount of radon for a long period of time or a high amount of radon for a short period of time.

The probability of contracting lung cancer is like a blind folded person tossing darts at dartboard. If the person tosses a single dart at a time, it is probable that it will take a considerable period of time before the person strikes the bulls eye.

On the other hand, if the person throws a handful of darts at a time, it is likely that less time will pass before the person strikes the bulls eye.

This analogy can be used to understand that the probability of an alpha particle striking a sensitive part of a lung cell in a manner that will cause cancer depends on dose and time of exposure, or
Lung cancer risk from radon is a function of:

• Radon concentration one is exposed to
• Amount of time one is exposed to it

Scientific Basis for Radon Health Risk Estimates

The effects of radon have been around a long time. Its effects were first noted as an unknown disease in the 1400’s. Lymphosarcoma was first identified in autopsies conducted in 1879 on European miners.

In modern times (1950’s to present), a higher than expected occurrence of lung cancer has been noted in uranium miners within the U.S., Czechoslovakia, France and Canada. Excess lung cancers have also been observed in other underground (not uranium) miners in Newfoundland, Sweden, Britain, France, China, and the U.S.

The presence of radon at elevated levels in above ground structures, such as homes, commercial buildings and schools was not well known until the mid 1980s. Remember, you cannot see or smell radon. Many homes and schools have been measured with radon levels in excess of underground mine concentrations.

Today the effects of radon are well known. The issue is not if radon causes cancer, but rather, how to control the radon exposure in our homes, workplaces, and schools.

EPA & Surgeon General Recommend That People Not Have Exposures Above 4 pCi/L On A Long-Term Basis

Based upon current and past studies, the EPA established a guidance for non-occupational exposures to radon. This guidance level was arrived at by analyzing both the health risks and the cost of fixing buildings with elevated levels. That is, the 4.0 pCi/L guidance is both a health and an economic based number.

The 4.0 pCi/L guidance is not a safety standard. Levels below 4.0 pCi/L still represent some risk. Even the outdoor air contains some radon. So, avoid making comments such as “the house tested safe,” or “there is no radon in the home.” Just because a house is below the EPA’s action level does not mean that there is no risk at all.

The conclusion that radon is a serious health risk is supported not only by the US EPA, but also the American Lung Association, the National Academy of Sciences and the National Council on Radiation Protection, among others.

How Does Radon Rank As A Cancer Causing Agent?

Due to the amount and strength of data that has been collected, radon is placed in the highest category of cancer causing agents. This category is referred to as Group A, which contains materials that are known to cause cancer in humans.

Being a Group A carcinogen certainly underscores the reasons there are concerns about radon. Being a Group A carcinogen also strengthens concerns about liability when a home or commercial building is sold. This is why radon testing has become more common at the time of sale.

How Does Radon Compare To Other Causes Of Death?

The comparison above is from the US EPA’s Citizens Guide to Radon. It compares the estimated number of deaths in the U.S. due to radon, with other more widely known causes of death. This comparison provides one reason why the EPA and other health organizations are so concerned about the radon issue. Furthermore, because radon is so easy to detect and also easy to fix, one can see why radon detection and remediation has become such a priority.

The US EPA and the National Academy of Sciences estimate that approximately 11% of the lung cancer deaths in the United States each year can be attributed to radon exposure. This translates to somewhere between 15,000 and 22,000 radon-induced lung cancer deaths each year in the U.S. This includes radon-induced cancer in both smokers and non-smokers.

Applying the U.S. data to the rate of lung cancer deaths in the state of Colorado for the year 2000 and also adjusting for the higher radon exposure in Colorado, it is estimated that 350 lung cancer deaths occur each year in Colorado due to radon exposure.

Notes: per Colorado Dept of Public Health, there were 1,426 lung cancer deaths (LCD) recorded in Colorado during the year 2000. Assuming these were lifetime residents exposed to the Colorado average long-term radon exposure of 2.59 pCi/L, one can factor the U.S. data as follows:

18,600 radon LCD (US1995) X 2.59 pCi/L (Colo. Avg.) X 1,426 Colorado LCD (2000) = 350 radon induced Colo. LCD/year
157,400 total LCD (US 1995) X 1.25 pCi/L (US average)

Radon is a Serious National Health Problem

The U.S. EPA’s concerns about radon are shared by many other independent health based agencies.
During the mid 1980s, the EPA was perceived by some as taking a “Chicken Little” attitude towards radon. That is, they were accused of making too much out of the issue. After all, radon is something that you cannot see or smell. It has been with us for a long time - so what’s the big deal?

However, after several other health based organizations reviewed the data that the National Academy of Sciences used to develop the EPA’s health risk assessments, they joined the EPA as Cooperative Partners to assist in educating the public about this significant environmental health concern.

In addition to the entities listed on the slide, the EPA is joined by many cooperative partners such as the National Association of Counties, The American Lung Association, The National Environmental Health Association.

Is Your Area the Only Area Where Radon Concerns Exist?

NO! Since the late 1980’s, radon measurements have been taken throughout the United States. This data has been collected and compared to geological formations to yield the map shown above. This map was originally developed for the purpose of establishing the degree of radon reduction methods that should be incorporated into the construction of new homes and buildings. However, it has served as a tool for focusing public awareness efforts on radon. It has also become a tool for relocation companies and lenders to develop their radon testing policies. The zone classifications are based upon being able to predict the likelihood of finding certain ranges of radon concentrations when conducting short-term measurements (as is often done at the time of a real estate transaction).

Key:

• Zone 1: Equal to, or greater than, 4.0 pCi/L
• Zone 2: Between 2.0 pCi/L and 4.0 pCi/L
• Zone 3: Less than 2.0 pCi/L

In comparing zones on the map above, one should remember that the US EPA and Surgeon General recommend that people not be exposed, on a long-term basis, to levels of radon in excess of 4.0 pCi/L. Additionally, one should realize that significant variations can occur within a county and there is no substitute for testing to verify individual conditions.

Testing for Radon

Radon Measurement Key Points

• There is no "totally safe" level of radon exposure

• 4 picoCuries per liter is the "action level" recommended by the EPA

• All radon problems can be fixed

• Radon levels in homes can typically be reduced to between 2-4 picoCuries per liter

• EPA's Testing Checklist

How to Test for Radon

There are reliable ways to measure indoor radon for short-term test periods that last only a few days, and for long-term test periods that may range from a few months to more than a year. Using recommended measurement devices, you can determine the radon potential of the home under "worst case conditions" (short-term test), or measure actual radon exposure under normal living conditions, (long-term test).

Homebuyers and sellers often prefer to have a radon test performed by a trained professional tester. In that case, EPA strongly recommends the use of a qualified radon measurement professional who has been trained in the proper placement of radon measurement devices and the interpretation of their results.

Short Term Tests

Often, at the time of sale, it is desirable to know a building's potential for radon exposure, independent of how the building is currently used. Short-term tests are typically conducted over a two or three day period. Results of short-term tests represent the radon potential of the home, rather than the actual exposure encountered under normal living conditions, unless residents keep the home's windows and doors closed year-round. That's because EPA guidelines for short-term radon tests require "Closed-House Conditions," to promote maximum radon concentration during the brief test period.

The placement of the device within the home must follow the manufacturer's instructions and is dependent on whether or not the test is being conducted for a real estate transaction.

Short-term tests are usually 2 to 7 days long and are done under "closed-house" conditions that begin at least 12 hours before the test and remain in effect for the duration of the test.

Closed House Conditions

• Exterior windows and doors are kept shut, except for normal entrance and exit.
• Fans and blowers which move air from the outside of the house to the inside, or exhaust inside air to the outside, are turned off, including swamp coolers
• Whole house fans should be off.
• Air conditioners should be put on "recycle" or "max.-cool," but not on the "fresh air" setting.
• Combustion or makeup air to gas fired appliances are NOT to be closed.
• The house can be occupied during testing, provided the "closed house" conditions described above are maintained.
• If testing during warm weather, keep the air-conditioning on and set the fan to recycle indoor air. Don't use the "fresh air" setting. Evaporative coolers, sometimes called "swamp coolers", should be turned off during the test, to avoid bringing outdoor air into the house.

Short-term, "closed house" radon tests should not be conducted during rainy weather, especially when the rain is accompanied by persistent winds. Changes in barometric pressure and other forces can cause indoor radon levels to rise during a rain storm and skew the test results higher than found under otherwise normal conditions.

Note: Placing the test device in a closed room or leaving doors and windows open during the test is improper and can invalidate a test.

Radon Test Devices

There are several devices on the market. EPA recommends that you begin with a short-term test device placed in the home for a minimum of two days. The devices in most home test kits are actually small containers of activated charcoal. Look for kits approved by one of the national certification programs (NEHA NRPP or NRSB).

You can purchase a kit from hardware stores or other retail outlets, as well as through non-profit organizations such as the National Safety Council (800-767-7236). Most of the kits range in price from $10 to $20. The cost usually includes the test device, the price of postage to mail the detector back to the laboratory, and the written report you receive by return mail.

There are two types of short-term test devices: 

• Integrating Devices, which measure radon and provide an average reading over the time of the test; and
• Continuous Radon Monitors, which measure radon and provide hourly readings as well as an overall average. 

It is not appropriate to use "Grab Samples," which test for less than 48 hours, as this is more of a diagnostic device and will not provide a representative radon potential measurement for the home.

If a short-term radon test is conducted correctly for a minimum of two days, under closed-house conditions, one can reasonably say: 

• If the result is less than 4.0 pCi/L, the annual average of the home under normal lived-in conditions is also likely to be less than 4.0 pCi/L.
• If the level is at or above 4.0 pCi/L, the house has the potential to average more than 4.0 pCi/L, and you should consider follow-up testing or taking action to reduce (mitigate) the radon in the home. 

Test Device Location 

The location of a radon test depends upon whether the test is being done for a real estate transaction or not. Since the purpose of the first, short-term test is to be able to identify homes that are clearly below 4.0 pCi/L, it is necessary to place the test device in a part of the home that would be expected to have the highest radon level.

The device should be placed in a room that is frequently occupied, but where high humidity in the air would not be expected. Examples of good locations would be bedrooms, dining rooms, and family rooms. Never place the device in a closet, crawl-space, storage area, kitchen, garage or bathroom.

In order to have confidence in the radon reading, the device should be placed in the lowest occupied space, for non-real estate transactions. A finished basement is normally chosen in those parts of the country that typically have basements.

In the case of a real estate transaction, the device should be placed in the lowest portion of the house that could be finished and occupied by future occupants.

If the radon measured is below 4.0 pCi/L, there is good reason to believe that the rest of the home is also below 4.0 pCi/L. Furthermore, if the closed-house test protocols are followed, there is good reason to believe that a low short-term test result (below 4.0 pCi/L) means that the average radon throughout the year will probably also be below 4.0 pCi/L, during normal use of the house.

Remember, short-term tests determine the radon potential of a home, independent of how future homeowners may operate or occupy the house.

Test Device Placement

A proper location must be selected to obtain an accurate measurement of radon in air that represents the breathing space of the home. The test device should be at least 20 inches from the floor, 4 inches from another object, 12 inches from an exterior wall, and 3 feet from an outside window. The device can be placed near an interior wall, perhaps on a book shelf, but should be at least four inches from the wall or the back of the shelf, to allow good air circulation.

•  3 feet from windows or exterior doors
• At least 20 inches above floor
• 4 inches from other objects
• Where it won't be disturbed
• Away from drafts
• Out of direct sunlight
• Not on hot or warm  surfaces

Devices that are designed to be hung by a string should be approximately 12 inches from the ceiling.

Test devices should also be located away from drafts and should not be placed in rooms with excess humidity.

Long-Term Tests - Actual Radon Exposure 

For the occupants of a home, actual radon exposure depends on how they use the home, where in the home the occupants spend their time, and how much freshair is brought into the living area. Since these factors may vary over time, the only reliable way of measuring the actual radon exposure is to conduct a long-term test for at least three months, under normal living conditions.

In the past, prospective homeowners have often been reluctant to purchase a home before performing a long-term test, for fear of not being able to correct a radon problem afterward. However, improved technology and the proven durability of radon mitigation systems have served to reduce much of that concern.

This does not mean that a short-term test is less valuable as part of a home inspection process; but rather, if the results of that test show a potential radon concern, a long-term test can more accurately show actual average radon levels. By conducting a long-term test after moving into a home, the homeowner can control test conditions and, if needed, make decisions on how a mitigation system will be installed.

The placement of the test device within the home must be in accordance with the manufacturer's instructions.

Test Results

If you perform the short-term test and the results are higher than 4.0 pCi/L, the EPA recommends you take further action. The next step should be to retest the home on a long term basis, ideally for a year, then decide if mitigation is necessary.

However, if the initial short-term test finds radon levels are significantly elevated, such as 10 pCi/L or more, you may want to repeat the short term test using a different test device to confirm the radon is still elevated. You can then average the two results and base your mitigation on the average.

The health risk from radon is cumulative, increasing over time if the radon level is elevated and not corrected. The health risks from radon occur over a long period of time and radon concentrations vary from season to season. An average radon level, measured over all four seasons, is a better indicator of actual health risk over time.

On the other hand, if your initial readings are significantly elevated, you should take action to quickly confirm these readings and then proceed to mitigate the home. Again, you may want to repeat the short-term test, using a different test device to confirm the radon is still elevated, then average the two results and base your mitigation on the average. 

Testing for Radon Decay Products

Radon decay products can also be measured using a special monitor that reports in Working Levels (WL). This can be done as an initial measurement or, more typically, after initial measurements have identified a potential concern in commercial buildings or homes with relatively low initial radon readings. The EPA guidance for radon decay products (comparable to 4.0 pCi/L of radon) recommends people should avoid long-term exposures in excess of 0.02 WL of radon decay products.

Testing Water for Radon

Radon in the ground can dissolve into water that finds its way to a well. When well water that contains radon is brought directly into a building, the dissolved gas is released indoors as the water leaves the faucet, showerhead or other outlet.

The amount of radon brought into the building will depend upon the amount of water used and the amountof radon in the water. Given typical water usage rates and radon concentrations found in wells, this entry mechanism only accounts for about 1-2% of the radon that enters homes in the U.S.

Most indoor radon comes from the soil. Thus, most remediation efforts concentrate on reducing the entry of radon from soil rather than water. As a rule of thumb, it takes 10,000 pCi/L in the water to add 1pCi/L to the air in a home, after the radon dilutes and dissipates within the large volume of air indoors. This is above and beyond that which comes from the soil.

The US EPA has recommended maximum contaminant levels (MCL) ranging from a low of 300 pCi/L to as high as 4,000 pCi/L of water for community water supplies. The regulation, as proposed, would not impact private wells, and no firm implementation date has been set.

Radon Mitigation

Radon Mitigation Key Elements

Radon Resistant New Construction

Some homebuilders add construction elements to new homes that help make the homes radon-resistant. Some go so far as to install a full system with fan, even though building codes in most areas do not specifically require radon-resistant construction features. In some states, some homebuilders include radon-resistant construction elements as a value-added feature, or when requested by homebuyers.

There are advantages to installing a system when building a house:

• The piping can be easily concealed in a chase;

• The vent pipe can exit the roof and appear as a normal roof penetration;

• The sub-grade can be prepared to make it easy to collect radon; and.

• In many cases these systems work passively without need for fans.

This figure illustrates the basic concept of a typical "soil depressurization" radon control system installed during the construction of a home. These systems draw radon and other soil gases from beneath the floor and upward through a pipe that exits above the roof. Soil air travels readily through the layer of gravel or sand that usually forms the base for a concrete slab.

Other options include a soil-gas collection system consisting of a loop of perforated plastic pipe buried inside the foundation footing, or a loop of gas-permeable matting laid on the sub-grade material directly under the slab and connected to a riser pipe.

The pipe riser should be routed through the interior of the building if possible, to allow the riser to be warmed, thus creating a natural stack effect. When this riser is combined with the gas-collecting system component installed below the slab, it can draw significant amounts of radon from beneath the home. The performance of this natural convection system is enhanced by sealing openings in the slab and walls so the air drawn up through the system comes from beneath the building rather than from within the building.

The efficiency of these passive systems is further enhanced when the riser pipe is routed through the warmest spaces in the home, such as the wall-cavity plumbing chase where the furnace and/or hot water flues are located. The radon vent should be dedicated only the radon reduction system and must not be connected to any combustion flues. Allowance is always made for adding a suction fan to the vent pipe, usually in the attic area, if needed later to increase system capabilities.

This passive-system approach is usually not chosen for retrofit mitigation of homes, because existing houses lack the specialized gas-collecting system component, such as perforated pipe, that is installed ony during new construction.  Test the home to be sure it reduces the radon to levels you desire.

Ask your builder about radon resistant features; and if a system is installed.

See below for EPA publications with more information.

Consumer Checklists

Radon Testing Checklist

Downloadable Copy Below

This checklist provided by the EPA can help ensure accurate radon test results will be obtained. Radon testing is not a complicated process, but must be done properly. Otherwise, the test results may not be accurate and more testing may have to be done. Disturbing or interfering with the test device or the closed-house conditions will invalidate the test results.

The seller or a certified tester should be able to confirm that all the items in this checklist have been followed. If the tester cannot confirm this, another test should be performed.

EPA's Testing Checklist

Before the radon test:

• Notify occupants of the importance of proper testing conditions. Give occupants written instructions or this checklist and explain the directions carefully.
• If conducting the test yourself, use a radon measurement device approved by the national certification programs and follow the manufacturer's instructions that come with the device.
• If you use a testing professional, hire a nationally certified individual and ask to see his or her identification. The contractor's identification number should be clearly visible on the test report.
• The test should include method(s) to prevent or detect interference with testing conditions or with the testing device itself.
• Conduct the radon test for a minimum of 48 hours. Certain devices must be exposed for more than the 48-hour minimum.
• Check to see if an active radon reduction system is in the house. Before taking a short-term test lasting less than 4 days, make sure the system, if any, is operating at least 24 hours before the beginning of the test.
• Short-term radon testing, which lasts for no more than a week in length, is to be conducted under closed-house conditions. Note: Closed-house conditions means keeping all windows closed, keeping doors closed except for normal entry and exit, and not operating fans or other machines which bring in air from outside. Fans that are part of a radon reduction system, or small exhaust fans operating for only short periods of time, may run during the test.
• When doing short-term testing lasting less than 4 days, it is important to maintain closed-house conditions for at least 12 hours before the beginning of the test and for the entire test period. Do not operate fans or other machines which bring in air from the outside.

During the radon test:

• Maintain closed-house conditions during the entire time of a short-term test, especially for tests shorter than one week in length.
• Operate the home's heating and cooling systems normally during the test. For tests lasting less than one week, only operate air conditioning units which recirculate interior air.
• Do not disturb the test device at any time during the test.
• If a radon reduction system is in place, make sure the system is working properly and will be in operation during the entire radon test.

After the radon test:

• If a high radon level is confirmed, fix the home. See the Home Buyer's and Seller's Guide for recommendations for steps such as contacting a qualified radon reduction contractor to lower the home's radon level. The homeowner or the professional radon tester should be able to verify that the test followed recommended protocols.

EPA Checklist for Selecting a Contractor

Downloadable Copy Below

The EPA's Consumer's Guide to Radon Reduction provides the following guidelines for dealing with a radon mitigation contractor:

Choose a contractor to fix a radon problem just as you would choose someone to do other home repairs. It is wise to get more than one estimate, to ask for references, and to contact some of those references to ask if they are satisfied with the contractors' work. EPA suggestions for finding qualified radon contractors can be found at the end of the following checklist.

• When evaluating and comparing contractors, it is helpful to ask the following questions:
  • Will the contractor provide references or photographs, as well as test results of ‘before' and ‘after' radon levels of past radon reduction work?
  • Can the contractor explain what the work will involve, how long it will take to complete, and exactly how the radon reduction system will work?
  • Does the contractor charge a fee for any diagnostic tests? Although many contractors give free estimates, they may charge for diagnostic tests - these tests help determine what radon reduction system should be used, but are not always necessary.
  • Did the contractor inspect your home's structure before giving you an estimate?
  • Did the contractor review the quality of your radon measurement results and determine if EPA testing procedures were followed? This is a requirement of most certification programs.
• Compare the contractors' proposed costs and consider what you will get for your money. Take into account the following: a system that is less expensive to install may have higher operating and maintenance costs than a system that is more expensive to install; the best system for your house may be the more expensive option; and the quality of the building material will effect how long the system lasts (or may not maintain the aesthetic value of the home).
• Do the contractors' proposals and estimates include:
  • Proof of liability insurance and licensed?
  • Proof of state or national certification?
  • Diagnostic testing prior to design and installation of a radon reduction system (not always necessary)?
  • Installation of a warning device to caution you if the radon reduction system is not working correctly?
  • Testing after installation to make sure the radon reduction system works well?
  • A guarantee to reduce radon levels to 4 pCi/L or below, and if so, for how long?

The Contract

Ask the contractor to prepare a contract before any work starts. Carefully read the contract before you sign it. Make sure everything in the contract matches the original proposal. The contract should describe exactly what work will be done prior to and during the installation of the system, what the system consists of, and how the system will operate. Carefully consider optional additions to your contract which may add to the initial cost of the system, but may be worth the extra expense. Typical options might include a guarantee that the contractor will adjust or modify the system to reach the promised radon level, or, an extended warranty and/or a service plan

Elements that should be included in the contract:

• The total cost of the job, including all taxes and permit fees; how much, if any, is required for a deposit; and when payment is due in full.
• The time needed to complete the work.
• An agreement by the contractor to obtain necessary permits and follow required building codes.
• A statement that the contractor carries liability insurance and insured to protect you in case of injury to persons, or damage to property, while the work is being done.
• A guarantee that the contractor will be responsible for damage and clean up after the job.
• Details of warranties, guarantees, or other optional features, including the acceptable resulting radon level.
• A declaration stating whether any warranties or guarantees are transferable if you sell your home.
• A description of what the contractor expects the homeowner to do (e.g., make the work area accessible) before work begins.

Consumer FAQ's

What is radon?

Why should I be concerned?

It has been shown in carefully controlled studies on animals, and on hard-rock miners, and most recently confirmed in residential case-control studies, that the effects of the radon decay products (due to prolonged exposure to elevated levels of radon) can significantly increase the potential of lung cancer. Radon is regarded as a Group A carcinogen; that is, it is known to cause cancer in humans with prolonged exposure. Many buyers are concerned about their health risk, as well as property resale value and want to test for and correct radon concerns. The United States Environmental Protection Agency and Surgeon General recommend that people not have long-term exposures in excess of 4.0 pico Curies per liter (pCi/L).

If I find a home with a radon problem should I look for another home?

The presence of high levels of radon should not keep you from buying the home of your dreams. If a properly performed test indicates an elevated level of radon in the home you wish to purchase, it is likely other homes in the same area will have elevated radon. So, if you like the house, consider taking a reasoned approach that will confirm levels and reduce the radon. Perhaps the best news about radon is that radon can be reduced, either before you buy the home, or after you buy it and move in. Of all the problems a house may have, radon is one of the easiest to identify and fix!

How do I test for radon?

Over the last 15 years, reliable testing devices and methods have been developed to determine indoor radon exposures. When using approved measurement devices, you can either determine the radon potential over a short period of time, or an average of radon exposure over a longer period of time.

• Radon Potential:

This is a short-term test, typically 2-5 days. It is conducted under closed building conditions 12 hours prior to and all during test. The test device is deployed on the lowest occupiable level of the home. This is commonly used at time of resale.

• Occupant Exposure:

This is a long term test, at least 91 days, up to one year. It is conducted under normal lived-in conditions without special closed building conditions. The device is deployed on lowest occupied level of home. It is commonly used outside of a real estate transaction, or used as the basis of escrow fund release, especially if a short-term test has shown results between 4 and 10 pCi/L.

Could there be radon in my water?

Yes, radon can dissolve in the groundwater and be released into the air of the home when it is used for showers, laundry, and other purposes. The concern with radon in water is not widespread and is primarily associated with homes whose water supplies are from wells or public water supplies that use groundwater. The major concern is not with drinking the water, but rather with the additional amount of radon added into the breathing space beyond that which comes from the soil. Normal radon in air tests will measure this contribution, if the house is occupied during testing. It takes a lot of radon in the water to have a measurable effect on the indoor radon concentrations. As a rule of thumb, it takes 10,000 pCi/L in the water to add one additional pCi/L of radon in the air. So always test the air first, before testing or becoming concerned with radon in the water. Your radon testing professional should be able to provide guidance.

How do I treat radon?

Radon is mitigated by installing a system that will draw the radon-laden soil gas from beneath the foundation and exhaust it outside of the building, far enough away from windows and other openings that it will not reenter. A mitigation system typically consists of a plastic pipe connected to the soil either through a hole in a slab, via a sump lid connection, or access beneath a plastic sheet in a crawl space. Attached to the pipe is a quiet, continuously operating fan that discharges the radon outdoors.

The type of mitigation system is a function of the construction of the home, rather than the radon concentrations that exist. A home with more than one foundation can present challenges to collecting the soil gas from under all portions of the building. However, talented mitigation contractors typically can connect multiple systems together so that only one fan system is required. Crawlspace foundations can be more costly, since the contractor needs to install a high density plastic sheet over the soil, seal it to the walls and then route the piping to the fan. However, the added benefit of reducing moisture in the crawlspace, in addition to reducing radon, can be a real plus.

• Average U.S. installation cost: $1,200
• Expected life span of fan: 11 years
• Fan replacement cost: $145-300
• Periodic maintenance: none

What impacts the cost of mitigation?

The cost of a mitigation system is a function of the extra effort taken by the contractor to conceal the system and to maintain the aesthetic value of your home. Although a system routed up the outside of the house will reduce radon quite well, it may not be as aesthetically pleasing as one that was routed through the interior of the house with trim installed to conceal it. An increasing number of buyers are getting involved in how these systems will be installed, or waiting until they occupy the house to better control the manner in which their system will be installed.

How do I find qualified radon measurement and mitigation contractors?

Most states recognize qualified credentialing organizations that certify radon measurement and mitigation professionals as well as analytical laboratories. Lists of these trained individuals can be found on the websites indicated below. In addition, your state may also have a listing on the state public health department website. Homeowners should also ask for references; require proof of certification, including agreement to follow protocols and codes of ethics; ask for proof of insurance including workers' compensation; and ask for a clear contract with details of guarantee and warranty.

Credentialing organizations:

• NEHA NRPP: (National Environmental Health Association - National Radon Proficiency Program) www.radongas.org
• NRSB: (National Radon Safety Board) www.nrsb.org

Do-It-Yourself Manual

Protecting Your Home From Radon© (2nd Edition)

The first edition of this book was written in 1993, to assist what was thought to be an occasional do-it-yourself homeowner.  In reality, the number of individuals wanting to reduce radon levels themselves was much higher than anticipated.  In addition, the manual was being utilized to better understand the radon mitigation process prior to hiring a contractor, and to design systems installed into homes during construction. 

The overwhelming success of the book led to the distribution of several thousand copies to individuals and libraries.  Its popularity identified the need to address the process of hiring contractors and installing passive and active systems in new home construction.  The second edition, now readily available, has these two substantive additions. 

This detailed manual describes the most common methods for reliably reducing radon in a home.  Written in a non-technical format, the book includes step-by-step instructions and illustrations to guide homeowners through the radon mitigation process. 

Cost $29.95

EPA Publications

The US EPA is a great resource for information and publications. The publications indicated below are available for download by clicking on the "PDF Version" link next to the description.

For more publications and other EPA resources, go to  www.epa.gov/radon/pubs

	Home Buyer's and Seller's Guide to Radon This booklet is intended for anyone who is buying or selling a home, real estate and relocation professionals, home inspectors and others. [EPA 402-K-06-093, November 2006] PDF Version (PDF, 43 pp, 1MB)
	A Citizen's Guide to Radon The guide to protecting yourself and your family from radon. This recently revised guidance offers strategies for testing your home for radon and discussions of what steps to take after you have tested, discussions of the risk of radon and radon myths. EPA 402-K-07-009, Revised May 2007] PDF Version (PDF, 16 pp, 859KB)
	Consumer's Guide to Radon Reduction How to Reduce Radon Levels in Your Home... You have tested your home for radon, but now what? This recently revised booklet is for people who have tested their home for radon and confirmed that they have elevated radon levels -- 4 picoCuries per liter (pCi/L) or higher. This booklet can help you: Select a qualified contractor to reduce the radon levels in your home, Determine an appropriate radon reduction method, and Maintain your radon reduction system. [EPA 402-K-06-094, December 2006] PDF Version (PDF, 20 pp, 602KB)
	A Radon Guide for Tenants This guide, created by the Environmental Law Institute (ELI) with EPA's review, is for people who rent their apartments or houses. The guide explains what radon is, and how to find out if there is a radon problem in your home. The guide also talks about what you can do if there are high radon levels in your home.  [EPA 402-K-98-004, 1996] PDF Version (PDF, 10 pp, 50 KB)
	Building Radon Out: A Step-by-Step Guide on How to Build Radon-Resistant Homes This 81-page, fully illustrated guide contains all the info you need in one place to educate home builders about radon-resistant new construction (RRNC), including: Basic questions and detailed answers about radon and RRNC; Specific planning steps before installing a system; Detailed installation instructions with helpful illustrations; Tips and tricks when installing a system, Marketing know-how when dealing with homebuyers; and, Architectural drawings. [EPA 402-K-01-002, April 2001] PDF Version (PDF, 84 pp, 5.52MB)

To Order EPA Publications:

You can order Indoor Air Quality publications from EPA's National Service Center for Environmental Publications (NSCEP):

U.S. Environmental Protection Agency
National Service Center for Environmental Publications (NSCEP)
P.O. Box 42419
Cincinnati, OH 45242-0419

Website:     www.epa.gov/nscep
Phone:       1-800-490-9198
Fax:           (301) 604-3408
E-mail:       nscep@bps-lmit.com

NSCEP operates a Toll-free phone service for EPA Publication assistance with live customer service representative assistance Monday through Friday from 9:00am-5:30pm eastern time. Voice Mail is available after operating hours. You can fax or e-mail your publication requests. For technical assistance with NSCEP web pages, write to: nscep_nepis.tech@epa.gov.  Indicate the EPA Document Number, which is bolded, when ordering from NSCEP.