Office of Air and Radiation (6101)

EPA Document #402-K92-001

Published: May 1992

Co-sponsored by The U.S. Environmental Protection Agency,

U.S. Department of Health and Human Services (Centers for Disease Control), and the

U.S. Public Health Service

EPA Recommends:

Test your home for radon -- it's easy and inexpensive.

Fix your home if your radon level is 4 picocuries per liter (pCi/L) or higher.

Radon levels less than 4 pCi/L still pose a risk, and in many cases may be reduced.

Radon is estimated to cause about 14,000

deaths per year. However, this number could

range from 7,000 to 30,000 deaths per year

The numbers of deaths from other causes are

taken from 1990 National Safety Council

reports.

Table of Contents

OVERVIEW

HOW DOES RADON GET INTO YOUR HOME?

HOW TO TEST YOUR HOME

WHAT YOUR TEST RESULTS MEAN

-- Radon and Home Sales

-- Radon in Water

HOW TO LOWER THE RADON LEVELS IN YOUR HOME

THE RISK OF LIVING WITH RADON

RADON RISK CHARTS

RADON MYTHS

STATE RADON CONTACTS

OVERVIEW

Radon is a cancer-causing, radioactive gas.

You can't see radon. And you can't smell it or taste it. But it may be a problem in your home.

Radon is estimated to cause many thousands of deaths each year. That's because when you breathe air containing radon,

you can get lung cancer. In fact, the Surgeon General has warned that radon is the second leading cause of lung cancer

in the United States today. Only smoking causes more lung cancer deaths. If you smoke and your home has high

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radon levels, your risk of lung cancer is especially high.

Radon can be found all over the U.S.

Radon comes from the natural (radioactive) breakdown of uranium in soil, rock and water and gets into the air you

breathe. Radon can be found all over the U.S. It can get into any type of building - homes, offices, and schools - and

build up to high levels. But you and your family are most likely to get your greatest exposure at home. That's where you

spend most of your time.

You should test for radon.

Testing is the only way to know if you and your family are at risk from radon. EPA and the Surgeon General

recommend testing all homes below the third floor for radon. EPA also recommends testing in schools.

Testing is inexpensive and easy - it should only take a few minutes of your time. Millions of Americans have already

tested their homes for radon.

You can fix a radon problem.

There are simple ways to fix a radon problem that aren't too costly. Even very high levels can be reduced to acceptable

levels.

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HOW DOES RADON GET INTO YOUR HOME?

Radon is a radioactive gas. lt comes from the natural decay of uranium that is found in nearly all soils. It typically moves up through

the ground to the air above and into your home through cracks and other holes in the foundation. Your home traps radon inside,

where it can build up. Any home may have a radon problem. This means new and old homes, well-sealed and drafty homes, and

homes with or without basements.

Radon from soil gas is the main cause of radon problems. Sometimes radon enters the home through well water (see "Radon in

Water" below). In a small number of homes, the building materials can give off radon, too. However, building materials rarely cause

radon problems by themselves.

RADON GETS IN THROUGH:

1. Cracks in solid floors

2. Construction joints

3. Cracks in walls

4. Gaps in suspended floors

5. Gaps around service pipes

6. Cavities inside walls

7. The water supply

Nearly 1 out of every 15 homes in the U.S. is estimated to have elevated radon levels. Elevated levels of radon gas have been found

in homes in your state. Contact your state radon office for general information about radon in your area. While radon problems may

be more common in some areas, any home may have a problem. The only way to know about your home is to test.

Radon can be a problem in schools and workplaces, too. Ask your state radon office about radon problems in schools and

workplaces in your area.

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HOW TO TEST YOUR HOME

You can't see radon, but it's not hard to find out if you have a radon problem in your home. All you need to do is test for radon.

Testing is easy and should only take a few minutes of your time.

The amount of radon in the air is measured in "picocuries per liter of air," or "pCi/L." Sometimes test results are expressed in

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Working Levels (WL) rather than picocuries per liter (pCi/L). There are many kinds of low-cost "do-it-yourself" radon test kits you

can get through the mail and in hardware stores and other retail outlets. Make sure you buy a test kit that has passed EPA's testing

program or is state-certified. These kits will usually display the phrase "Meets EPA Requirements." If you prefer, or if you are

buying or selling a home, you can hire a trained contractor to do the testing for you. Make certain you hire an EPA-qualified or statecertified radon tester. Call your state radon office for a list of these testers.

There are Two General Ways to Test for Radon:

SHORT-TERM TESTING: The quickest way to test is with

short-term tests. Short-term tests remain in your home for two

days to 90 days, depending on the device. "Charcoal canisters,"

"alpha track," "electret ion chamber," "continuous monitors," and

"charcoal liquid scintillation" detectors are most commonly used

for short-term testing. 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. If

you need results quickly, however, a short-term test followed by a

second short-term test may be used to decide whether to fix your home.

LONG-TERM TESTING: Long-term tests remain in your home for more than 90 days. "Alpha track" and "electret"

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.

How To Use a Test Kit:

Follow the instructions that come with your test kit. If you are doing a short-term test, close your windows and outside doors and

keep them closed as much as possible during the test. (If you are doing a short-term test lasting just 2 or 3 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 just 2 or 3

days during unusually severe storms or periods of unusually high winds.) The test kit should be placed in the lowest lived-in level of

the home (for example, the basement if it is frequently used, otherwise the first floor). It should be put in a room that is used

regularly (like a living room, playroom, den or bedroom) but not your kitchen or bathroom. Place the kit at least 20 inches above the

floor in a location where it won't be disturbed - away from drafts, high heat, high humidity, and exterior walls. Leave the kit in place

for as long as the package says. Once you've finished the test, reseal the package and send it to the lab specified on the package right

away for study. You should receive your test results within a few weeks.

Testing is easy and should only take a few minutes of your time.

EPA Recommends the Following Testing Steps:

Take a short-term test. If your result is 4 pCi/L or higher (0.02 Working Levels [WL] or higher) take a follow-up test (Step 2)

to be sure.

1. 

Follow up with either a long-term test or a second short-term test. For a better understanding of your year-round average radon

level, take a long-term test. If you need results quickly, take a second short-term test. The higher your initial short-term test

result, the more certain you can be that you should take a short-term rather than a long-term follow up test. If your first shortterm test result is several times the action level - for example, about 10 pCi/L or higher - you should take a second short-term

test immediately

2. 

If you followed up with a long-term test: Fix your home if your long-term test result is 4 pCi/L or more (0.02 Working Levels

[WL] or higher). If you followed up with a seconds short-term test: The higher your short-term results, the more certain you

can be that you should fix your home. Consider fixing your home if the average of your first and second test is 4 pCi/L or

higher (0.02 Working Levels [WL] or higher).

3. 

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WHAT YOUR TEST RESULTS MEAN

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 in all cases, most homes today can be reduced to 2 pCi/L or below.

Sometimes short-term tests are less definitive about whether or not your home is above 4 pCi/L. This can happen when your results

are close to 4 pCi/L. For example, if the average of your two short-term test results is 4.1 pCi/L, there is about a 50% chance that

your 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.

If your living patterns change and you begin occupying a lower level of your home (such as a basement) you should retest your

home on that level.

Even if your test result is below 4 pCi/L, you may want to test again sometime in the future.

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RADON AND HOME SALES

More and more, home buyers and renters are asking about radon levels before they buy or rent a home. Because real estate sales

happen quickly, there is often little time to deal with radon and other issues. The best thing to do is to test for radon NOW and save

the results in case the buyer is interested in them. Fix a problem if it exists so it won't complicate your home sale. If you are planning

to move, call your state radon office for EPA's pamphlet "Home Buyer's and Seller's Guide to Radon," which addresses some

common questions. During home sales:

Buyers often ask if a home has been tested, and if elevated levels were reduced.

Buyers frequently want tests made by someone who is not involved in the home sale. Your state office (see below) has a list of

qualified testers.

Buyers might want to know the radon levels in areas of the home (like a basement they plan to finish) that the seller might not

otherwise test.

Today many homes are built to prevent radon from coming in. Your state or local area may require these radon-resistant construction

features. Radon-resistant construction features usually keep radon levels in new homes below 2 pCi/L. If you are buying or renting a

new home, ask the owner or builder if it has radon-resistant features.

Test your home now and save your results. If you find high radon levels, fix your home before you decide to sell it.

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RADON IN WATER

Compared with radon entering the home through soil, radon entering the home through water

will in most cases 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, it has

been found in well water. If you've tested the air in your home and found a radon problem, and

your water comes from a well, contact a lab certified to measure radiation in water to have your

water tested. If you're on a public water supply and are concerned that radon may be entering

your home through the water, call your public water supplier.

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. Unfortunately, point-of-use treatment will not reduce most of the inhalation risk from

radon.

If you've tested the air in your home and found a radon problem, and your water comes from a well, have your

water tested.

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.

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HOW TO LOWER THE RADON LEVEL IN YOUR HOME

Since there is no known safe level of radon, there can always be some risk. But the risk can be reduced by lowering the radon level

in your home.

A variety of methods are used to reduce radon in your home. In some cases, sealing cracks in floors and walls may help to reduce

radon. In other cases, simple systems using pipes and fans may be used to reduce radon. Such systems are called "sub-slab

depressurization," and do not require major changes to your home. These systems remove radon gas from below the concrete floor

and the foundation before it can enter the home. Similar systems can also be installed in houses with crawl spaces. Radon

contractors use other methods that may also work in your home. The right system depends on the design of your home and other

factors.

Ways to reduce radon in your home are discussed in EPA's "Consumer's Guide to Radon Reduction." You can get a copy from your

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state radon office.

The cost of making repairs to reduce radon depends on how your home was built

and the extent of the radon problem. 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 house costs about $1,200 for a contractor to fix, although

this can range from about $500 to about $2,500.

Lowering high radon levels requires technical knowledge and special skills. You

should use a contractor who is trained to fix radon problems. The EPA Radon

Contractor Proficiency (RCP) Program [Now the National Radon Proficiency

Program (RPP)] tests these contractors. EPA provides a list of RCP contractors

(now referred to as "Mitigation Service Providers") on the WWW and to state

radon offices. A mitigation contractor who has passed the EPA test will carry a

special RPP identification card. A trained mitigation contractor can study the

radon problem in your home and help you pick the right treatment method.

Check our proficiency internet site or contact your state radon office for names of

qualified or state certified radon mitigation contractors in your area. 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.

If you plan to fix the problem in your home yourself, you should first contact your

state radon office for EPA's technical guide, "Radon Reduction Techniques for

Detached Houses."

You should also test your home again after it is fixed to be sure that radon levels have been reduced. Most radon reduction systems

include a monitor that will alert you if the system needs servicing. In addition, it's a good idea to retest your home sometime in the

future to be sure radon levels remain low.

Most homes can be fixed for about the same cost as other common home repairs.

Radon and Home Renovations

If you are planning any major structural renovation, 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. Most homes can be fixed for about the same cost as other common home

repairs.

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THE RISK OF LIVING WITH RADON

Radon gas decays into radioactive particles that can get trapped in your lungs when you breathe. As they break down further, these

particles release small bursts of energy. This can damage lung tissue and lead to lung cancer over the course of your lifetime. Not

everyone exposed to elevated levels of radon will develop lung cancer. And the amount of time between exposure and the onset of

the disease may be many years.

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

of cancer in humans (underground miners). Additional studies on more typical populations are under way.

Smoking combined with radon is an especially serious health risk. Stop smoking and lower your radon level to reduce your lung

cancer risk.

Children have been reported to have greater risk than adults of certain types of cancer

from radiation, but there are currently no conclusive data on whether children are at

greater risk than adults from radon.

Your chances of getting lung cancer from radon depend mostly on:

How much radon is in your home

The amount of time you spend in your home

Whether you are a smoker or have ever smoked

Scientists are more certain about radon risks than risks

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from most other cancer-causing substances.

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RADON RISK IF YOU SMOKE

Radon

Level

If 1,000 people who smoked

were exposed to this level

over a lifetime...

The risk of cancer from

radon exposure

compares to...

WHAT TO DO:

Stop smoking and...

20

pCi/L

About 135 people could get

lung cancer

100 times the risk of

drowning Fix your home

10

pCi/L

About 71 people could get

lung cancer

100 times the risk of

dying in a home fire Fix your home

8 pCi/L About 57 people could get

lung cancer Fix your home

4 pCi/L About 29 people could get

lung cancer

100 times the risk of

dying in an airplane

crash

Fix your home

2 pCi/L About 15 people could get

lung cancer

2 times the risk of dying

in a car crash

Consider fixing

between 2 and 4 pCi/L

1.3

pCi/L

About 9 people could get lung

cancer

(Average indoor radon

level)

(Reducing radon levels

below 2 pCi/L is

difficult.)

0.4

pCi/L

About 3 people could get lung

cancer

(Average outdoor radon

level)

(Reducing radon levels

below 2 pCi/L is

difficult.)

Note: If you are a former smoker, your risk may be lower.

RADON RISK IF YOU HAVE NEVER SMOKED

Radon

Level

If 1,000 people who smoked

were exposed to this level

over a lifetime...

The risk of cancer from

radon exposure

compares to...

WHAT TO DO:

20

pCi/L

About 8 people could get lung

cancer

The risk of being killed

in a violent crime Fix your home

10

pCi/L

About 4 people could get lung

cancer Fix your home

8 pCi/L About 3 people could get lung

cancer

10 times the risk of dying

in an airplane crash Fix your home

4 pCi/L About 2 people could get lung

cancer The risk of drowning Fix your home

2 pCi/L About 1 person could get lung

cancer

The risk of dying in a

home fire

Consider fixing

between 2 and 4 pCi/L

1.3

pCi/L

Less than 1 person could get

lung cancer

(Average indoor radon

level)

(Reducing radon levels

below 2 pCi/L is

difficult.)

0.4

pCi/L

Less than 1 person could get

lung cancer

(Average outdoor radon

level)

(Reducing radon levels

below 2 pCi/L is

difficult.)

Note: If you are a former smoker, your risk may be higher.

It's never too late to reduce your risk of lung cancer. Don't wait to test and fix a radon problem. If you are a

smoker, stop smoking.

Go Back to Table of Contents

Some Common Myths About Radon

MYTH: Scientists are not sure that radon really is a problem.

FACT: Although some scientists dispute the precise number of deaths due to radon, all the major health organizations (like the

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Centers for Disease Control and Prevention, the American Lung Association and the American Medical Association) agree with

estimates that radon causes thousands of preventable lung cancer deaths every year. This is especially true among smokers, since

the risk to smokers is much greater than to non-smokers.

MYTH: Radon testing devices are not reliable and are difficult to find.

FACT: Radon testing can be conducted by a professionally trained EPA-listed or state-certified radon tester.

Active radon devices can continuously gather and periodically record radon levels to reveal any unusual swings in the radon level

during the test.

Reliable testing devices are also available through the mail, in hardware stores and other retail outlets. Call your state radon office

for a list of radon device companies that have met EPA requirements for reliability or are state-certified.

MYTH: Radon testing is difficult and time-consuming.

FACT: Radon testing is easy. You can test your own home or you can hire an EPA-listed or state-certified radon tester. Either

approach takes only a small amount of the homeowner's time or effort.

MYTH: Homes with radon problems cannot be fixed.

FACT: There are solutions to radon problems in homes. Thousands of home owners have already lowered elevated radon levels in

their homes. Radon levels can be readily lowered for $500 to $2,500. Call your state radon office for a list of contractors that have

met EPA requirements or are state-certified.

MYTH: Radon affects only certain types of homes.

FACT: Radon can be a problem in all types of homes such as old homes, new homes, drafty homes, insulated homes, homes with

basements and homes without basements. Construction materials and the way the home has been built may also affect radon levels.

MYTH: Radon is only a problem in certain parts of the country.

FACT: High radon levels have been found in every state. Radon problems do vary from area to area, but the only way to know the

home's radon level is to test.

MYTH: A neighbor's test result is a good indication of whether your home has a radon problem.

FACT: It is not. Radon levels vary from home to home. The only way to know if your home has a radon problem is to test it.

MYTH: Everyone should test his or her water for radon.

FACT: While radon gets into some homes through the water, it is important to first test the air in the home for radon. If high radon

levels are found and the home has a well, call the Safe Drinking Water Hotline at 1 800-426-4791, or your state radon office for

more information.

MYTH: It is difficult to sell a home where radon problems have been discovered.

FACT: Where radon problems have been fixed, home sales have not been blocked. The added protection could be a good selling

point.

MYTH: I have lived in my home for so long, it does not make sense to take action now.

FACT: You will reduce your risk of lung cancer when you reduce radon levels, even if you have lived with a radon problem for a

long time.

MYTH: Short-term tests cannot be used for making a decision about whether to reduce the home's high

radon levels.

FACT: Short-term tests may be used to decide whether to reduce the home's high radon levels. However, the closer the short-term

testing result is to 4 pCi/L, the less certainty there is about whether the home's year-round average is above or below that level.

Keep in mind that radon levels below 4 pCi/L still pose some risk and that radon levels can be reduced in some homes to 2 pCi/L or

below.

Go Back to Table of Contents

STATE RADON AND INDOOR AIR CONTACTS

[http://www.epa.gov/iaq/contacts.html]

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National Radon Hotline:

1 800/SOS-RADON

For other Indoor Air Hotlines: [www.epa.gov/iaq/iaqxline.html]

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FOR FURTHER INFORMATION

For more information on how to reduce your radon health risk, call your state radon office for copies of these guides:

Home Buyer's and Seller's Guide to Radon

Radon in Schools

Radon: A Physician's Guide

Consumer's Guide to Radon Reduction

Technical Support Document to the 1992 Citizens Guide to Radon

Other Radon-specific publications are located at: www.epa.gov/iaq/radon/pubs/

Other Indoor Air Quality-specific publications are located at: www.epa.gov/iaq/pubs/

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 mitigation, "Application of Radon Reduction Techniques for Detached Houses. "

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."

This guide ("A Citizen's Guide to Radon" - EPA Document #402-K92-001) is for sale by the:

U.S. Government Printing Office

Superintendent of Documents, Mail Stop: SSOP,

Washington, DC 20402-9328

ISBN 0-16-036222-9

Go Back to Table of Contents

Last Modified: March 22, 1999

http://www.epa.gov/iaq/radon/pubs/citguide.html

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