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EPA Recommends:
TABLE OF CONTENTSOverviewEPA has developed this guide to help home buyers and sellers address 8 key questions about radon:
PLEASE NOTE: The information in these pages have been modified slightly from the original Agency publication to reflect changes in technical terminology, specifically, in the descriptions of radon measurement and mitigation service providers participating in EPA's Radon Proficiency Program (RPP). This guide is for anyone buying or selling a home who wants to learn about radon.Radon is a cancer-causing, radioactive gasYou cannot see radon. And you cannot smell it or taste it. But it may be a problem in your home. That is because when you breathe air containing radon, you increase your risk of getting lung cancer. In fact, the Surgeon General has warned that radon is the second leading cause of lung cancer in the United States today. If you smoke and your home has high radon levels, your risk of lung cancer is especially high. You should test for radonTesting is the only way to find out your home's radon levels. EPA and the Surgeon General recommend testing all homes below the third floor for radon. You can fix a radon problemIf you find that you have high radon levels, there are ways to fix a radon problem. Even very high levels can be reduced to acceptable levels. If you are selling a home...EPA recommends that you test your home before putting it on the market and, if necessary, lower your radon levels. Save the test results and all information you have about steps that were taken to fix any problems. This could be a positive selling point. (See Sections 2(a) & (b) and 5(c) & (d) below for recommendations about how to test.) If you are buying a home...EPA recommends that you obtain the indoor radon level in a home you are considering buying. Ask the seller for radon test results. If the home has a radon reduction system, ask the seller for information about the system. If the home has not yet been tested, Sections 2(b) and 5(c) of this Guide make recommendations about how to test now. If you are buying a newly-constructed home, please refer to Section 4. The radon testing guidelines in the "Home Buyer's and Seller's Guide to Radon" have been developed specifically to deal with the time sensitive nature of home purchases and sales and the potential for radon device interference. The guidelines in the "Home Buyer's Guide" are somewhat different from the guidelines in other EPA publications which provide radon testing and reduction information for non-real estate situations. The "Home Buyer's Guide" recommends three short-term testing options when long-term testing is not possible. The "Home Buyer's Guide" also recommends testing a home in the lowest level of the home which is currently suitable for occupancy. This is because a buyer may choose to live in a lower area of the home than that used by the seller. 1. WHY DO YOU NEED TO TEST FOR RADON?
|
|
Why you cannot estimate radon levels based on
state, local and neighborhood radon measurements |
2.
IF YOU ARE SELLING A HOME, WHAT SHOULD YOU DO?
If you are thinking of selling your home and you have already tested your home for radon, provide your test results to the buyer. Review the testing Checklist in Section 5(e) to make sure that the test was done correctly.
No matter what kind of test you took, a potential buyer may ask for a new test especially if:
you took a test and the Checklist items were not met;
| you have renovated or altered your home since you tested;
| the buyer plans to live in a lower level of the house than you do, such
as a basement which is suitable for occupance but is not currently lived
in;
| or, your State requires disclosure of Radon information to buyers. | |
b.
If the home has not yet been tested for radon...Have a test taken as soon as possible. If you can, test your home before putting it on the market because this may save time during real estate transactions. You should test in the lowest level of the home which is suitable for occupancy and finished. This means testing in the lowest level that you currently live in or a lower level not currently used, but which a buyer could use for living space without renovations. The result of the radon test is important information about your home's radon level that potential buyers may want to know.
You can test your own home or hire an EPA-listed or state-certified radon tester. Call your state radon office for a list of these professional radon testers. If you test your own home, carefully follow the Checklist in Section 5(e).
3. IF YOU ARE BUYING A HOME, WHAT SHOULD YOU DO?
a.
If the home has already been tested for radon...If you are thinking of buying a home, you may either decide to accept the test results from the seller, ask the seller to do another test, or you may ask for a new test to be conducted by an EPA-listed or state-certified radon tester.
If you decide to accept the seller's test, make sure that the seller (or whoever took the test) followed the testing Checklist in Section 5(e) and that he or she can confirm that all the items were followed. If you plan to use the seller's test, find out as soon as possible from the seller:
the results of the previous test; and
| who conducted the previous test: the homeowner, a radon professional or
some other person; and
| where in the home the previous test was taken, especially if you may
plan to live in a lower level of the home. For example, the test may have
been taken on the first floor; however, you may want to live in a basement
which is not currently lived in but which is suitable for occupancy
without renovation.
| what, if any, structural changes or alterations have been made to the
house since the test was done. Such changes might affect radon levels. | |
If you decide that a new test is needed, you should discuss it with the seller as soon as possible. If you decide to use an EPA-listed or state-certified radon tester, contact your state radon office for a list of radon testing companies.
Make sure that a radon test is done as soon as possible. You should consider including provisions in the contract specifying who should conduct the test, what type of test to do, when to do the test, and how the seller and the buyer will share the test results, test costs and, if necessary, when radon mitigation measures should be taken and who should pay for them.
Make sure that the test is done in the lowest level of the home suitable for occupancy. This means the lowest level that you are going to use as living space which is finished or does not require renovations prior to use. A state or local radon official or an EPA-listed or state-certified radon tester can help you make some of these decisions.
If you decide to finish or renovate an unfinished area of the home in the future, radon tests should be taken before and after the area is finished. Radon reduction costs could be incurred if high levels are found in that area. Generally, it is less expensive to install a radon reduction system before or during renovations rather than afterwards.
4. IF YOU ARE BUYING A NEWLY BUILT HOME, WHAT SHOULD YOU DO?
New
homes can be built with radon-resistant
features that minimize radon entry and allow easier fixing of radon
problems that could occur later. These features cost less if installed during
construction than if added to an existing home. In most new homes, use of
radon-resistant features will keep radon levels to below 2 pCi/L.
Builders can incorporate radon-resistant features into the homes they build. Some states, counties and local jurisdictions may adopt radon-resistant construction features in their building codes, which builders must then follow. Radon-resistant construction standards can be applied depending on the radon potential in a particular area. Many builders already use radon resistant building features.
New home buyers should ask if radon-resistant construction techniques have been built into the new home they are considering for purchase. Buyers should also ask whether information about radon is available. For custom-built homes, the buyer should discuss radon-resistant features with the builder, including the cost.
Occupants of newly constructed homes should have their homes tested for radon. A long-term test will provide a reading that is more representative of the home's year-round average radon level. However, short-term tests (as described in Section 5(b)) may be used to determine if elevated radon levels exist.
5. HOW CAN YOU GET RELIABLE RADON TEST RESULTS?
Even though you cannot see or smell
radon, it is not hard
to find out if you have a radon problem in your home.
Since you cannot see or smell radon, special equipment is needed to detect it. You can buy radon devices in retail stores when you want to test your own home, send away for radon devices from EPA-listed Analytical Service Providers that offer mail order services, or you can hire an EPA-listed or state-certified radon tester who will test using radon devices that are appropriate for the situation.
Preventing or Detecting Test Interference
There is a potential for test interference in real estate transactions. There are a number of ways to prevent or detect test interference such as:
Print-out report which frequently records radon or decay product levels
to detect unusual swings;
| Motion detectors to determine whether the test device has been moved or
testing conditions have changed;
| Proximity detectors to reveal the presence of people in the room which
may correlate to possible changes in radon levels during the test;
| Record of barometric pressure to identify weather conditions which may
have affected the test;
| Temperature record to help assess whether doors and windows have been
opened; and
| Taping windows shut to ensure closed house conditions (see Section
5(e)). | |
Home buyers and sellers should evaluate these and other features when selecting a radon test alternative. Refer to the "Protocols for Radon and Radon Decay Measurements in Homes" for information about radon testing devices and associated device interference features.
Some of the most common radon testing devices are listed below. Because new testing devices may be listed by EPA or your state, you may want to check with your state radon office before you test to get the most up-to-date information.
Passive Devices
Passive radon testing devices do not need power to function. they include radon detectors such as charcoal canisters, alpha-track detectors, and charcoal liquid scintillation devices that are available in hardware stores, drug stores, other stores, and by mail, and electret ion chamber detectors generally only available through laboratories. They are exposed to the air in the home for a specified period of time and then sent to a laboratory for analysis. Both short-term and long-term passive devices are generally inexpensive. Some of these devices may have features that offer more resistance to test interference or disturbance than other passive devices. Professional radon testers may use any of these devices to measure the home's radon level.
Active Devices
Active radon testing devices require power to function. Active radon detectors such as continuous radon monitors and continuous working level monitors require operation by trained testers. They work by continuously measuring and recording the amount of radon or its decay products in the air of the home. Many of these devices provide a report of this information which can reveal any unusual or abnormal swings in the radon level during the test period. A professional tester can explain this report to you. In addition, some of these devices are specifically designed to deter and detect test interference. Currently, some of the technically advanced active devices offer the most extensive device interference features. Although these tests may cost more, they may ensure a more reliable result.
General Information for All Devices:
A state or local radon official can explain the differences between devices and recommend the ones which are most appropriate for your needs and expected testing conditions. In addition, EPA's Radon Measurement Protocols include technical information about the differences between devices.
Make sure the radon device is listed by EPA's Radon Proficiency Program (RPP) or is state-certified. The device may display the phrase "Meets EPA Requirements" or "EPA listed." Your state radon office or a radon tester can tell you more about radon testing devices.
Certain precautions should be followed to avoid interference during the test period. Refer to the Checklist in Section 5(e) for more information about how to get a reliable test.
In some areas, companies may offer different types of radon service agreements. Some agreements let you pay a one-time fee that covers both testing, and if needed, radon reduction. Contact your state radon office to find out if these are available in your state.
The testing device(s) should be placed in the lowest level of the home suitable for occupancy. This means testing in the lowest level currently lived in or a lower level not currently used, such as a basement, which a buyer could use for living space without renovations. The test should be in a room to be used regularly (like a living room, playroom, den or bedroom) but not a kitchen, bathroom or laundry room.
| Whether you test for radon yourself or hire an EPA-listed or state-certified tester, all radon tests should be taken for a minimum of 48 hours. A longer period of testing is required for some devices. |
There Are Two General Ways To Test Your Home for Radon:
LONG-TERM TESTING: Long-term tests remain in your home for more than 90 days. Alpha track, and electret ion chamber 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. 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, EPA recommends fixing the home.
SHORT -TERM TESTING: The quickest way to test is with short-term tests. Short-term tests remain in your home from two days to 90 days, depending on the device. There are two groups of devices which are more commonly used for short-term testing. The passive device group includes alpha track detectors, charcoal canisters, charcoal liquid scintillation detectors, and electret ion chambers. The active device group consists of different types of continuous monitors. (see Section 5(a) above for more information.) 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. However, if you need results quickly, short-term testing may be used to decide whether to fix the home.
If you are testing in a real estate transaction and you need results quickly, any of the following three ways to conduct Short-Term Tests are acceptable for determining whether the home should be fixed. Any real estate test for radon should include steps to prevent or detect device interference (see Section 5(a)).
| Short-Term Testing Options | What to do Next |
|---|---|
| Passive: Take an initial short-term test for at least 48 hours. After the first test has been completed, take a follow-up short-term test for at least 48 hours. or Take two short-term tests at the same time in the same location for at least 48 hours. |
Fix the home if the average of two tests is 4 pCi/L or more. |
| Active: Test the home with a continuous monitor for at least 48 hours. |
Fix the home if the average radon level is 4 pCi/L or more. |
When
you are taking a short-term test, close your windows and outside doors and
keep them closed as much as possible during the test, except for normal entry
and exit. If you are taking a short-term test lasting less than 4 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 less
than 4 days during severe storms or periods of high winds.
Place the test device at least 20 inches above the floor in a
location where it will not be disturbed and where it will be away from drafts,
high heat, high humidity, and exterior walls. Leave the test kit in place for
as long as the test instructions say. Once you have finished the test, reseal
the package and send it immediately to the lab specified on the package for
analysis. You should receive your test results within a few weeks. If you need
results quickly, you should find out how long results will take and, if
necessary, request expedited service.
| When choosing a short-term testing option... There are tradeoffs among the short-term test options. One test followed by another test (sequential) would most likely give a better representation of the seasonal average. Two tests taken at the same time (simultaneous) would improve the precision of this radon test. Both active and passive devices may have features which help to prevent test interference. Your state radon office can help you decide which option is the best for you. |
Follow
this Checklist carefully so that you get the most accurate radon test
results. 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
closed-house conditions will invalidate the test results. The seller, or an EPA-listed
or state-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 taken.
| Notify occupants of the importance of
proper testing conditions. Give occupants written instructions or this
document and explain the directions carefully. |
|
| If you conduct the test yourself, use a
radon measurement device listed in EPA's Radon
Proficiency Program (RPP) or certified by your state and follow
the manufacturer's instructions that come with the device.
If you use a testing professional, hire only an EPA-listed or state-certified individual and ask to see his or her photo 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 fan, if any, is operating at least 24 hours
before the beginning of the test. |
|
| EPA recommends that short-term radon
testing, which lasts for no more than a week in length, be done under
closed-house conditions. Closed-house conditions mean 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. Note that 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. |
| Maintain closed-house conditions during he
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, operate only 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. |
| If a high radon level is found, fix the
home. Section 6 of this guide
recommend the next steps you should take, such as contacting a
qualified radon reduction contractor to lower the home's radon level. |
|
| Be sure that you or the professional radon
tester can demonstrate or provide information to ensure that the
testing conditions were not violated during the testing period. |
In many cases, home buyers and sellers may decide to have the radon test done by a professional radon tester. Make sure that the company or individual(s) you hire is listed in EPA's Radon Proficiency Program or your state's certification program, if it has one.
EPA's Radon Proficiency Program (RPP) is designed to help you get reliable radon tests. RPP participants are required to show their ability to make accurate tests and follow quality assurance and EPA test guidelines. EPA has provided a list of RPP participants in your state. These reports list Analytical Service providers (companies who provide radon test results and testing devices) and listed individuals in your area who follow EPA's residential radon testing requirements. Make sure you ask to see the professional radon tester's photo I.D. card.
| WHAT WILL A PROFESSIONAL RADON TESTER DO? An EPA-listed or state-certified radon tester knows the proper conditions, test devices, and guidelines to get a reliable radon test. A professional radon tester can also:
Your state radon office may also have information about certification requirements for professional radon testers. Contact your State radon office for information about EPA-listed and state-certified contractors. |
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 for all homes, the radon levels in some homes today can be reduced to 2 pCi/L or below.
| Radon Test Results Measured in Two Different Units
Your radon test results may be reported in either picocuries per Liter of Air (pCi/L) or Working Levels (WL). If your test result is in pCi/L, EPA recommends you fix the home if your radon level is 4 pCi/L or higher. If the test result is in WL, EPA recommends you fix the home if the working level is 0.02 WL or higher. |
Sometimes short-term tests are less definitive about whether the home is at or above 4 pCi/L. This can happen when your results are close to 4 pCi/L. For example, if the average of the two short-term tests is 4.1 pCi/L, there is about a 50% chance that the 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.
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 in humans (underground miners). Additional studies on more typical populations are under way.
Your radon measurement will give you an idea of your risk of getting lung cancer from radon. Your chances of getting lung cancer from radon depend mostly on:
The home's radon level; and
| The amount of time you spend in your home; and
| Whether you are a smoker or have ever smoked. | |
Smoking combined with radon is an especially serious health risk. If you smoke or are a former smoker, the presence of radon greatly increases your risk of lung cancer. If you stop smoking now and lower the radon level in your house, you will reduce your lung cancer risk.
Go to the Radon Risk Comparison Charts
6. WHAT SHOULD YOU DO IF YOU FIND A HIGH RADON LEVEL?
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. It is preferable to correct a radon problem before placing your home on the market because then you have more time to address a radon problem. If elevated levels are found during the real estate transaction, the buyer and seller should discuss the timing and costs of the radon reduction, as with any other aspect of the home purchase and sale.
The cost of making repairs to reduce radon depends on how your home was built 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.
A
variety of methods can be used to reduce radon in homes. Sealing cracks and
other openings in the foundation is a basic part of most approaches to radon
reduction. EPA does not recommend the use of sealing alone to reduce radon
because, by itself, sealing has not been shown to lower radon levels
significantly or consistently. In most cases, systems with pipes and fans are
used to reduce radon. Such systems are called "subslab
depressurization," and do not require major changes to your home. These
systems prevent radon gas from entering the home from below the concrete floor
and the foundation. Similar systems can also be installed in homes with crawl
spaces. 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. As with any other house-hold appliance, there would be costs
associated with the operation of the radon reduction system.
Ways to reduce radon are discussed in EPA's "Consumer's Guide to Radon Reduction." Call your state radon office to get a copy.
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.
Radon and home renovationsIf 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 the renovation. If your test results indicate a radon problem, radon resistant techniques can be inexpensively included as part of the renovation. Because major renovations can change the level of radon in any home, always test again after work is completed. |
Contractors who participate and become listed in EPA's National Radon Proficiency Program (RPP) are qualified 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 and State or local codes;
and
| Make sure the finished system effectively reduces radon levels to
acceptable levels. | |
Picking someone to fix your radon problem is much like choosing a contractor for other home repairs; you may want to get references and more than one estimate. Call your state radon office for a list of the names of EPA listed or state-certified radon reduction contractors in your area. Your state radon office may also have information about certification requirements for these contractors.
You
should use a radon reduction contractor who is listed as being proficient (in
the current National Radon Proficiency Program (RPP)) as a Residential
Mitigation Service Provider. This Program tests the technical knowledge of
contractors to ensure that they can correct radon problems. EPA-listed
Residential Mitigation Service Providers must follow specific guidelines which
make certain that their work meets minimum quality standards. EPA-listed
Residential Mitigation Service Providers carry photo I.D. cards and are listed
in the National RPP Reports.
EPA-listed Residential Mitigation Service Providers are required to pass an
initial exam and then follow the Radon
Mitigation Standards. These standards are available from your state
radon office. EPA-listed Residential Mitigation Service Providers are also
required to review radon measurement results before beginning radon reduction
work. In addition, an EPA-listed Residential Mitigation Service Provider must
recommend that the home be tested again by an independent EPA-listed or
state-certified radon measurement service provider after completing radon
mitigation work to confirm that elevated levels have been reduced.
Should the Company Performing Your Radon Test Also be Your Radon Reduction Contractor?Be aware that there is potential conflict of interest if you use the same company to conduct both the test and the radon mitigation of the home. If the same radon testing professional also offers to do radon mitigation of the home, make sure that the testing is done according to the Testing Checklist. EPA's Radon Proficiency Program works to protect home buyers and sellers. Make sure you only hire professional measurement and mitigation contractors who are EPA-listed or state-certified. Always ask to see the contractor's I.D. card. You should also consider getting more than one cost estimate and asking for references from radon measurement and mitigation companies in your area. Some states have additional certification requirements, and may require the homeowner to sign a waiver if one firm conducts both radon measurements and mitigations. Contact your state radon office. |
Compared with radon entering the home through soil, radon entering the home through water in most cases will be a small source of risk. Radon gas can enter the home through well water. It can be released into the air you breathe when water is used for showering and other household uses. Research suggests that swallowing water with high radon levels may pose risks, too, although risks from swallowing water containing radon are believed to be much lower than those from breathing air containing radon.
While radon in water is not a problem in homes served by most public water supplies, radon has been found in well water. If you have tested the air in your home and found a radon problem, and your water comes from a well, have the water tested. If you are on a public water supply and are concerned that radon may be entering your home through the water, call your public water supplier. The testing device and procedures used to find out the radon levels of your home's water supply are different from the device and procedures used to test your home's indoor air levels for radon.
Radon problems in water can be readily fixed. The most effective treatment is to remove radon from the water before it enters the home. This is called point-of-entry treatment. Treatment at your water tap is called point-of-use treatment. Point-of-use devices usually only treat a small portion of your water and are not effective in reducing radon risk in water.
If high radon levels are found and the home has a well, you can find publications and documents developed by EPA's Office of Ground Water and Drinking Water relating to radon in drinking water and the radon in drinking water rule at http://www.epa.gov/safewater/radon.html.
8. WHERE CAN YOU GET MORE INFORMATION ABOUT RADON?
For
more information on how to reduce your radon health risk, go to EPA's
Radon Home Page, or ask your state radon
office to send you these guides (the complete list of Radon-related
publications is available at http://www.epa.gov/iaq/radon/pubs),
you can find other Indoor Air-related publications at (http://www.epa.gov/iaq/pubs/):
Protocols for Radon and Radon Decay Product Measurements in Homes (call
your state radon contact
for a copy of the protocols).
| Citizen's Guide to Protecting Yourself and Your
Family from Radon
| Consumer's Guide to Radon Reduction | |
If you plan to make repairs yourself, be sure to contact your state radon office for a current copy of EPA's technical guidance on radon reduction, "Radon Reduction Techniques for Detached Houses -- Technical Guidance."
Contact the EPA's Drinking Water Hotline (1 800 426-4791) for information on radon in water.
SURGEON GENERAL HEALTH ADVISORY"Indoor radon gas is a national health problem. Radon causes thousands of deaths each year. Millions of homes have elevated radon levels. Homes should be tested for radon. When elevated levels are confirmed, the problem should be corrected." |
| Consumers need to know about the health of a house they are
considering purchasing, including whether there is a radon problem,
and if so, how to fix it. The Home Buyer's and Seller's Guide to Radon
provides practical consumer information that every home buyer needs to
know.
Consumer Federation of America |
For sale by the U.S. Government Printing Office:
Superintendent of Documents,
Mail Stop: SSOP,
Washington, DC 20402-9328.
U.S. Environmental Protection Agency document number: 402-r-93-003,
1ast printing - March 1993,
U.S. EPA/Office of Air and Radiation/Office of Radiation and Indoor Air,
Mail Stop-6604J,
401 M Street, S.W.,
Washington, DC 20460.
You can call your State Radon Contact for a
free copy of this guide.
http://www.epa.gov/iaq/radon/pubs/hmbyguid.html
Last Modified: July 21, 1999
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