Mold Resources

Introduction to Molds
Basic Mold Cleanup
Ten Things You Should Know About Mold
Asthma and Mold
Floods/Flooding
Health and Mold
Homes and Mold
Indoor Air Regulations and Mold
Large Buildings and Mold
Schools and Mold and Indoor Air Quality
Other Mold-Related Resources/Links

Frequent Questions for other Indoor Air Topics

Indoor Air Quality | Radon | Schools | Smoke-free Homes

The publication, "A Brief Guide to Mold, Moisture, and Your Home", is available in HTML and PDF (278KB file size) formats. [EPA 402-K-02-003]

The publication, "Mold Remediation in Schools and Commercial Buildings", is available in HTML and PDF (5MB file size) formats. [EPA 402-K-01-001, March 2001]

Order publications from IAQ INFO and EPA's NSCEP. Use the EPA Document Number when ordering.

Introduction to Molds

Molds produce tiny spores to reproduce. Mold spores waft through the indoor and outdoor air continually. When mold spores land on a damp spot indoors, they may begin growing and digesting whatever they are growing on in order to survive. There are molds that can grow on wood, paper, carpet, and foods. When excessive moisture or water accumulates indoors, mold growth will often occur, particularly if the moisture problem remains undiscovered or un-addressed. There is no practical way to eliminate all mold and mold spores in the indoor environment; the way to control indoor mold growth is to control moisture.

Basic Mold Cleanup

The key to mold control is moisture control. It is important to dry water damaged areas and items within 24-48 hours to prevent mold growth. If mold is a problem in your home, clean up the mold and get rid of the excess water or moisture. Fix leaky plumbing or other sources of water. Wash mold off hard surfaces with detergent and water, and dry completely. Absorbent materials (such as ceiling tiles & carpet) that become moldy may have to be replaced.

Ten Things You Should Know About Mold

Potential health effects and symptoms associated with mold exposures include allergic reactions, asthma, and other respiratory complaints.
There is no practical way to eliminate all mold and mold spores in the indoor environment; the way to control indoor mold growth is to control moisture.
If mold is a problem in your home or school, you must clean up the mold and eliminate sources of moisture.
Fix the source of the water problem or leak to prevent mold growth.
Reduce indoor humidity (to 30-60% ) to decrease mold growth by: venting bathrooms, dryers, and other moisture-generating sources to the outside; using air conditioners and de-humidifiers; increasing ventilation; and using exhaust fans whenever cooking, dishwashing, and cleaning.
Clean and dry any damp or wet building materials and furnishings within 24-48 hours to prevent mold growth.
Clean mold off hard surfaces with water and detergent, and dry completely. Absorbent materials such as ceiling tiles, that are moldy, may need to be replaced.
Prevent condensation: Reduce the potential for condensation on cold surfaces (i.e., windows, piping, exterior walls, roof, or floors) by adding insulation.
In areas where there is a perpetual moisture problem, do not install carpeting (i.e., by drinking fountains, by classroom sinks, or on concrete floors with leaks or frequent condensation).
Molds can be found almost anywhere; they can grow on virtually any substance, providing moisture is present. There are molds that can grow on wood, paper, carpet, and foods.

Asthma and Mold

Molds can trigger asthma episodes in sensitive individuals with asthma. People with asthma should avoid contact with or exposure to molds.
EPA's Asthma web site
Allergy & Asthma Network/Mothers of Asthmatics (AAN/MA): (800) 878-4403; www.aanma.org
American Academy of Allergy, Asthma & Immunology (AAAAI): www.aaaai.org
American Lung Association: 1-800-LUNG-USA (1-800-586-4872); www.lungusa.org
Asthma & Allergy Foundation of America: (800) 7ASTHMA; www.aafa.org
Canadian Mortgage & Housing Corporation fact sheets on mold - www.cmhc-schl.gc.ca/en/burema/gesein/abhose/abhose_50.cfm
National Institute of Allergy and Infectious Diseases: www.niaid.nih.gov
National Jewish Medical and Research Center: (800) 222-LUNG (5864); www.njc.org

Floods/Flooding

Mold growth may be a problem after flooding. EPA's Fact Sheet: Flood Cleanup: Avoiding Indoor Air Quality Problems - discusses steps to take when cleaning and repairing a home after flooding. Excess moisture in the home is cause for concern about indoor air quality primarily because it provides breeding conditions for microorganisms. This fact sheet provides tips to avoid creating indoor air quality problems during cleanup. U.S. EPA, EPA Document Number 402-F-93-005, August 1993.
Federal Emergency Management Agency (FEMA): (800) 480-2520; www.fema.gov mitigation website: www.fema.gov/mit publications on floods, flood proofing, etc.
University of Minnesota, Department of Environmental Health & Safety - www.dehs.umn.edu/iaq/flood.html. "Managing Water Infiltration Into Buildings." A Systematized Approach for Remediating Water Problems in Buildings due to Floods, Roof Leaks, Potable Water Leaks, Sewage Backup, Steam Leaks and Groundwater Infiltration. Questions and comments may be directed to: Neil Carlson, M.S., CIH, Department of Environmental Health & Safety, University of Minnesota, or Arif Quraishi, M.E., Vice President, Special Projects, Indoor Environments Division, Institute for Environmental Assessment, Inc.

Health and Mold

Molds can trigger asthma episodes in sensitive individuals with asthma (See Asthma Section above); molds can also trigger allergies in sensitive individuals.
EPA's publication, Indoor Air Pollution: An Introduction for Health Professionals, assists health professionals (especially the primary care physician) in diagnosis of patient symptoms that could be related to an indoor air pollution problem. It addresses the health problems that may be caused by contaminants encountered daily in the home and office. Organized according to pollutant or pollutant groups such as environmental tobacco smoke, VOCs, biological pollutants, and sick building syndrome, this booklet lists key signs and symptoms from exposure to these pollutants, provides a diagnostic checklist and quick reference summary, and includes suggestions for remedial action. Also includes references for information contained in each section. This booklet was developed by the American Lung Association, the American Medical Association, the U.S. Consumer Product Safety Commission, and the EPA. EPA Document Reference Number 402-R-94-007, 1994.
Allergic Reactions - excerpted from Indoor Air Pollution: An Introduction for Health Professionals section on: Animal Dander, Molds, Dust Mites, Other Biologicals.
"A major concern associated with exposure to biological pollutants is allergic reactions, which range from rhinitis, nasal congestion, conjunctival inflammation, and urticaria to asthma. Notable triggers for these diseases are allergens derived from house dust mites; other arthropods, including cockroaches; pets (cats, dogs, birds, rodents); molds; and protein-containing furnishings, including feathers, kapok, etc. In occupational settings, more unusual allergens (e.g., bacterial enzymes, algae) have caused asthma epidemics. Probably most proteins of non-human origin can cause asthma in a subset of any appropriately exposed population."
Consult the Centers for Disease Control (CDC) website
CDC's National Center for Environmental Health (NCEH) has a toll-free telephone number for information and FAXs, including a list of publications: NCEH Health Line 1-888-232-6789.
CDC's "Molds in the Environment" Factsheet
Stachybotrys or Stachybotrys atra (chartarum) and health effects
CDC's "Questions and Answers on Stachybotrys chartarum and other molds"

Homes and Molds

The EPA publication, "A Brief Guide to Mold, Moisture, and Your Home", is available here in HTML and PDF formats. This Guide provides information and guidance for homeowners and renters on how to clean up residential mold problems and how to prevent mold growth. A printed version will be available soon.
Biological Pollutants in Your Home - This document explains indoor biological pollution, health effects of biological pollutants, and how to control their growth and buildup. One third to one half of all structures have damp conditions that may encourage development of pollutants such as molds and bacteria, which can cause allergic reactions -- including asthma -- and spread infectious diseases. Describes corrective measures for achieving moisture control and cleanliness. This brochure was prepared by the American Lung Association and the U.S. Consumer Product Safety Commission. EPA Document Reference Number 402-F-90-102, January 1990.
Moisture control is the key to mold control, the Moisture Control Section from Biological Pollutants in Your Home follows:
Moisture Control
Water in your home can come from many sources. Water can enter your home by leaking or by seeping through basement floors. Showers or even cooking can add moisture to the air in your home. The amount of moisture that the air in your home can hold depends on the temperature of the air. As the temperature goes down, the air is able to hold less moisture. This is why, in cold weather, moisture condenses on cold surfaces (for example, drops of water form on the inside of a window). This moisture can encourage biological pollutants to grow.
There are many ways to control moisture in your home:
Fix leaks and seepage. If water is entering the house from the outside, your options range from simple landscaping to extensive excavation and waterproofing. (The ground should slope away from the house.) Water in the basement can result from the lack of gutters or a water flow toward the house. Water leaks in pipes or around tubs and sinks can provide a place for biological pollutants to grow.
Put a plastic cover over dirt in crawlspaces to prevent moisture from coming in from the ground. Be sure crawlspaces are well-ventilated.
Use exhaust fans in bathrooms and kitchens to remove moisture to the outside (not into the attic). Vent your clothes dryer to the outside.
Turn off certain appliances (such as humidifiers or kerosene heaters) if you notice moisture on windows and other surfaces.
Use dehumidifiers and air conditioners, especially in hot, humid climates, to reduce moisture in the air, but be sure that the appliances themselves don't become sources of biological pollutants.
Raise the temperature of cold surfaces where moisture condenses. Use insulation or storm windows. (A storm window installed on the inside works better than one installed on the outside.) Open doors between rooms (especially doors to closets which may be colder than the rooms) to increase circulation. Circulation carries heat to the cold surfaces. Increase air circulation by using fans and by moving furniture from wall corners to promote air and heat circulation. Be sure that your house has a source of fresh air and can expel excessive moisture from the home.
Pay special attention to carpet on concrete floors. Carpet can absorb moisture and serve as a place for biological pollutants to grow. Use area rugs which can be taken up and washed often. In certain climates, if carpet is to be installed over a concrete floor, it may be necessary to use a vapor barrier (plastic sheeting) over the concrete and cover that with sub-flooring (insulation covered with plywood) to prevent a moisture problem.
Moisture problems and their solutions differ from one climate to another. The Northeast is cold and wet; the Southwest is hot and dry; the South is hot and wet; and the Western Mountain states are cold and dry. All of these regions can have moisture problems. For example, evaporative coolers used in the Southwest can encourage the growth of biological pollutants. In other hot regions, the use of air conditioners which cool the air too quickly may prevent the air conditioners from running long enough to remove excess moisture from the air. The types of construction and weatherization for the different climates can lead to different problems and solutions.
Should You Have the Air Ducts in Your Home Cleaned? - excerpt on duct cleaning and mold follows, please review the entire document for additional information on duct cleaning and mold.
You should consider having the air ducts in your home cleaned if:
There is substantial visible mold growth inside hard surface (e.g., sheet metal) ducts or on other components of your heating and cooling system. There are several important points to understand concerning mold detection in heating and cooling systems:
Many sections of your heating and cooling system may not be accessible for a visible inspection, so ask the service provider to show you any mold they say exists.
You should be aware that although a substance may look like mold, a positive determination of whether it is mold or not can be made only by an expert and may require laboratory analysis for final confirmation. For about $50, some microbiology laboratories can tell you whether a sample sent to them on a clear strip of sticky household tape is mold or simply a substance that resembles it.
If you have insulated air ducts and the insulation gets wet or moldy it cannot be effectively cleaned and should be removed and replaced.
If the conditions causing the mold growth in the first place are not corrected, mold growth will recur.

Indoor Air Regulations and Mold

Standards or Threshold Limit Values (TLVs) for airborne concentrations of mold, or mold spores, have not been set. Currently, there are no EPA regulations or standards for airborne mold contaminants.

Large Buildings and Mold

EPA has a number of resources available, you can start with "Building Air Quality: A Guide for Building Owners and Facility Managers" and the "Building Air Quality Action Plan"
Excerpt from the Building Air Quality: A Guide for Building Owners and Facility Managers, Appendix C - Moisture, Mold and Mildew:
How to Identify the Cause of a Mold and Mildew Problem.
Mold and mildew are commonly found on the exterior wall surfaces of corner rooms in heating climate locations. An exposed corner room is likely to be significantly colder than adjoining rooms, so that it has a higher relative humidity (RH) than other rooms at the same water vapor pressure. If mold and mildew growth are found in a corner room, then relative humidity next to the room surfaces is above 70%. However, is the RH above 70% at the surfaces because the room is too cold or because there is too much moisture present (high water vapor pressure)?
The amount of moisture in the room can be estimated by measuring both temperature and RH at the same location and at the same time. Suppose there are two cases. In the first case, assume that the RH is 30% and the temperature is 70^oF in the middle of the room. The low RH at that temperature indicates that the water vapor pressure (or absolute humidity) is low. The high surface RH is probably due to room surfaces that are "too cold." Temperature is the dominating factor, and control strategies should involve increasing the temperature at cold room surfaces.
In the second case, assume that the RH is 50% and the temperature is 70^oF in the middle of the room. The higher RH at that temperature indicates that the water vapor pressure is high and there is a relatively large amount of moisture in the air. The high surface RH is probably due to air that is "too moist." Humidity is the dominating factor, and control strategies should involve decreasing the moisture content of the indoor air.
Schools and Mold and Indoor Air Quality

The Agency's premier resource on this issue is the Indoor Air Quality Tools for Schools kit. Our schools-related resources on the web start at: epa.gov/iaq/schools.

The asthma companion piece for the IAQ Tools for Schools kit, titled Managing Asthma in the School Environment (epa.gov/iaq/schools/asthma) has been recently published. This publication has a section entitled Clean Up Mold and Moisture Control at: epa.gov/iaq/schools/asthma/eat-cumcm.htm

Excerpt from IAQ Tools for Schools kit companion piece, Managing Asthma in the School Environment:
Common Moisture Sources Found in Schools
Moisture problems in school buildings can be caused by a variety of conditions, including roof and plumbing leaks, condensation, and excess humidity. Some moisture problems in schools have been linked to changes in building construction practices during the past twenty to thirty years. These changes have resulted in more tightly sealed buildings that may not allow moisture to escape easily. Moisture problems in schools are also associated with delayed maintenance or insufficient maintenance, due to budget and other constraints. Temporary structures in schools, such as trailers and portable classrooms, have frequently been associated with moisture and mold problems.
Suggestions for Reducing Mold Growth in Schools
Reduce Indoor Humidity:
Vent showers and other moisture-generating sources to the outside.
Control humidity levels and dampness by using air conditioners and de-humidifiers.
Provide adequate ventilation to maintain indoor humidity levels between 30-60%.
Use exhaust fans whenever cooking, dishwashing, and cleaning in food service areas.
Inspect the building for signs of mold, moisture, leaks, or spills:
Check for moldy odors.
Look for water stains or discoloration on the ceiling, walls, floors, and window sills.
Look around and under sinks for standing water, water stains, or mold.
Inspect bathrooms for standing water, water stains, or mold.
Do not let water stand in air conditioning or refrigerator drip pans.
Respond promptly when you see signs of moisture and/or mold, or when leaks or spills occur:
Clean and dry any damp or wet building materials and furnishings within 24-48 hours of occurrence to prevent mold growth.
Fix the source of the water problem or leak to prevent mold growth.
Clean mold off hard surfaces with water and detergent, and dry completely.
Absorbent materials such as ceiling tiles, that are moldy, may need to be replaced.
Check the mechanical room and roof for unsanitary conditions, leaks, or spills.
Prevent moisture condensation:
Reduce the potential for condensation on cold surfaces (i.e., windows, piping, exterior walls, roof, or floors) by adding insulation.
Floor and carpet cleaning:
Remove spots and stains immediately, using the flooring manufacturer’s recommended techniques.
Use care to prevent excess moisture or cleaning residue accumulation and ensure that cleaned areas are dried quickly.
In areas where there is a perpetual moisture problem, do not install carpeting (i.e., by drinking fountains, by classroom sinks, or on concrete floors with leaks or frequent condensation).

Other Mold-Related Resources/Links

U.S. Environmental Protection Agency (EPA)

Indoor Air Quality Publications and Resources
An Office Building Occupant's Guide to IAQ - epa.gov/iaq/pubs/occupgd.html
Biological Contaminants - epa.gov/iaq/pubs/bio_1.html
IAQ Building Education and Assessment Model (I-BEAM) - I-BEAM updates and expands EPA's existing Building Air Quality guidance and is designed to be comprehensive state-of-the-art guidance for managing IAQ in commercial buildings. This guidance was designed to be used by building professionals and others interested in indoor air quality in commercial buildings. I-BEAM contains text, animation/visual, and interactive/calculation components that can be used to perform a number of diverse tasks. epa.gov/iaq/largebldgs/ibeam_page.htm
Building Air Quality: A Guide for Building Owners and Facility Managers (BAQ Guide) - epa.gov/iaq/largebldgs/baqtoc.html
Building Air Quality Action Plan (for Commercial Buildings) - epa.gov/iaq/largebldgs/actionpl.html
Floods/Flooding - epa.gov/iaq/pubs/flood.html
Mold Remediation in Schools and Commercial Buildings - epa.gov/iaq/molds/mold_remediation.html
For more subject-specific links, go to: epa.gov/iaq/schools/links.html, or epa.gov/iaq/asthma/links.html, or epa.gov/iaq/moreinfo.html.

Antimicrobial Information Hotline www.epa.gov/oppad001/
(703) 308-0127/(703) 308-6467(FAX)
Monday-Friday 8:00 AM - 5:00 PM EST
email: Info_Antimicrobial@epa.gov

The Antimicrobials Information Hotline provides answers to questions concerning current antimicrobial issues (disinfectants, fungicides, others) regulated by the pesticide law, rules and regulations. These cover interpretation laws, rules, and regulations, and registration and re-registration of antimicrobial chemicals and products. The Hotline also provide information health & safety issues on registered antimicrobial products, product label and the proper and safe use of these antimicrobial products.

How to Order Publications

These indoor air quality publications are also available through the IAQ INFO Clearinghouse.

IAQ INFO
P.O. Box 37133, Washington, DC 20013-7133
1-800-438-4318/703-356-4020
(fax) 703-356-5386
iaqinfo@aol.com
or, you can order these publications directly via EPA's National Service Center for Environmental Publications (NSCEP) (http://www.epa.gov/ncepihom/). web site. Your publication requests can also be mailed, called or faxed directly to:
U.S. Environmental Protection Agency
National Center for Environmental Publications (NSCEP)
P.O. Box 42419
Cincinnati, OH 42419
1-800-490-9198/(513) 489-8695 (fax)

Please use the EPA Document Number when ordering from NSCEP or from IAQ INFO.
Indoor Air - Radon (Rn)

Everyone should test their homes for one of the leading causes of lung cancer in the country: indoor radon gas. In some areas of the country, as many as one out of two homes has high levels of radon. Radon levels can soar during the colder months when residents keep windows and doors closed and spend more time indoors.
"Twenty-two thousand people die from lung cancer each year in the United States from exposure to indoor radon". "Yet Americans could help prevent these deaths and protect their families by testing their homes for radon as soon as possible." Christine Todd Whitman, Former EPA Administrator
National Radon Action Week is October 19-25, 2003
Assessment of Risks from Radon in Homes
The Agency has updated the estimates of lung cancer risks from indoor radon based on the National Academy of Sciences’ (NAS) report on radon, the Biological Effects of Ionizing Radiation (BEIR) VI Report. These new estimates will be used to update estimated lung cancer risks from radon in various publications, including “A Citizen’s Guide to Radon.”   Read More...
EPA Releases New Video on Radon in Real Estate
Breathing Easy: What Home Buyers and Sellers Should Know About Radon
EPA has added a new visual tool to its radon toolbox. The video satisfies a long-standing need for a short visual educational tool on how to best include radon in residential real estate transactions.
With a bit of light humor, the video covers the basics, including radon science, the lung cancer risk, home inspection, building a new home radon-resistant, testing and fixing a home, disclosure, state radon offices, hotline and web resources, and key radon numbers, e.g., EPA's action level and the U.S. indoor and outdoor averages.
The primary audiences are home buyers and sellers, and real estate sales agents and brokers. Home inspectors, mortgage lenders, other real estate practitioners, and radon services providers will also find the video helpful. Single copies of the video are free from IAQ-INFO (1-800-438-4318) in VHS format. Ask for [EPA 402-V-02-003 (TRT 13.10)]; copies in CD-ROM and DVD formats will also be available soon.
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-03-002, Revised February 2003] An Adobe Acrobat pdf version of the Guide is available here (consguid.pdf).
EPA Incorporates ASTMI E2121 By Reference
EPA has incorporated E2121 by reference and retained EPA’s Radon Mitigation Standards (RMS) in effect until at least 2006. This decision is consistent with the Office of Management and Budget (OMB) Circular A-119 on Federal participation in the development and use of voluntary consensus standards, and the National Technology Transfer and Advancement Act (NTTAA) of 1995. The policy discussion and response to comments paper is available here as a PDF file (final_e2121policy.pdf). If you have questions concerning this policy, contact either Philip Jalbert (jalbert.philip@epa.gov) or Eugene Fisher (fisher.eugene@epa.gov).
EPA Map of Radon Zones
The Map was developed using five factors to determine radon potential: indoor radon measurements; geology; aerial radioactivity; soil permeability; and, foundation type. Radon potential assessment is based on geologic provinces. Radon Index Matrix is the quantitative assessment of radon potential. Confidence Index Matrix shows the quantity and quality of the data used to assess radon potential. Geologic Provinces were adapted to county boundaries for the Map of Radon Zones.
Sections 307 and 309 of the Indoor Radon Abatement Act of 1988 (IRAA) directed EPA to list and identify areas of the U.S. with the potential for elevated indoor radon levels. EPA's Map of Radon Zones assigns each of the 3,141 counties in the U.S. to one of three zones based on radon potential:
Zone 1 counties have a predicted average indoor radon screening level greater than 4 pCi/L (pico curies per liter) (red zones)
Zone 2 counties have a predicted average indoor radon screening level between 2 and 4 pCi/L (orange zones)
Zone 3 counties have a predicted average indoor radon screening level less than 2 pCi/L (yellow zones)
An Adobe Acrobat pdf version of the map is available (suitable for printing): color - zonemapcolor.pdf (327KB file) | black & white - b&wmap.pdf (98KB file)
You can view your State's radon potential map by clicking on your State below.
Alabama || Alaska || Arizona || Arkansas || California || Colorado || Connecticut || Delaware || Florida || Georgia || Hawaii || Idaho || Illinois || Indiana || Iowa || Kansas || Kentucky || Louisiana || Maine || Maryland || Massachusetts || Michigan || Minnesota || Mississippi || Missouri || Montana || Nebraska || Nevada || New Hampshire || New Jersey || New Mexico || New York || North Carolina || North Dakota || Ohio || Oklahoma || Oregon || Pennsylvania || Rhode Island || South Carolina || South Dakota || Tennessee || Texas || Utah || Vermont || Virginia || Washington || West Virginia || Wisconsin || Wyoming
EPA Map of Radon Zones
The purpose of this map is to assist National, State, and local organizations to target their resources and to implement radon-resistant building codes. This map is not intended to be used to determine if a home in a given zone should be tested for radon. Homes with elevated levels of radon have been found in all three zones. All homes should be tested regardless of geographic location.
"A Citizen's Guide to Radon: The Guide to Protecting Yourself and Your Family From Radon (4th ed.)"
Co-sponsored by The U.S. Environmental Protection Agency,
U.S. Department of Health and Human Services, and the U.S. Public Health Service
Office of Air and Radiation
Indoor Environments Division (6609J)
EPA Document 402-K02-006, Revised May 2002

A Citizen's Guide to Radon - 4th ed.
Contents
Overview
How Does Radon Get Into Your Home?
How to Test Your Home
-- There are Two General Ways to Test for Radon
-- How to Use a Test Kit
What Your Test Results Mean
-- Radon and Home Sales
-- Radon in Water
How to Lower the Radon Levels in Your Home
-- Radon and Home Renovations
The Risk of Living With Radon
Radon Risk Charts
Radon Myths
State Radon Contacts
For Further Information
How to Order Publications
A PDF version of this guidance is also available (citizensguide4.pdf).
Please Note: The Spanish version of this publication, El Radon, reflects information that has NOT been updated from the 3rd. ed. A translation of this version into Spanish has been planned, please check back.
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 risk bar chart
Radon is estimated to cause thousands of cancer deaths in the U.S. each year.

* Radon is estimated to cause between 15,000 and 22,000 lung cancer deaths per year according to the National Academy of Sciences 1998 data. The numbers of deaths from other causes are taken from 2001 National Safety Council reports.
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 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 result in a high indoor radon level. 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 (see How to Test Your Home).
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.
New homes can be built with radon-resistant features.
Radon-resistant construction techniques can be effective in preventing radon entry. When installed properly and completely, these simple and inexpensive techniques can help reduce indoor radon levels in homes. In addition, installing them at the time of construction makes it easier and less expensive to reduce radon levels further if these passive techniques don't reduce radon levels to below 4 pCi/L. Every new home should be tested after occupancy, even if it was built radon-resistant.
How Does Radon Get Into Your Home?
Radon is a radioactive gas. It comes from the natural decay of uranium that is found in nearly all soils. It typically moves up through the ground to the air above and into your home through cracks and other holes in the foundation. Your home traps radon inside, where it can build up. 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:
Any Home may have a radon problem

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
house cutaway
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, daycare and childcare facilities, and workplaces in your area.
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 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. If you prefer, or if you are buying or selling a home, you can hire a qualified tester to do the testing for you. You should contact your state radon office about obtaining a list of qualified testers. You can also contact a private radon proficiency program for lists of privately certified radon professionals serving your area. For links and information, visit www.epa.gov/radon/proficiency.html .
There are Two General Ways to Test for Radon:
citizen's guide - house
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 (see Home Sales).
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. Heating and air-conditioning system fans that re-circulate air may be operated. Do not operate fans or other machines which bring in air from outside. Fans that are part of a radon-reduction system or small exhaust fans operating only for short periods of time may run 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 analysis. You should receive your test results within a few weeks.
EPA Recommends the Following Testing Steps:
Step 1.
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.
Step 2.
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 short-term test result is more than twice EPA's 4 pCi/L action level, you should take a second short-term test immediately.
Step 3.
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 second 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). (see also Home Sales)
What Your Test Results Mean
test your home now 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.
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. You can also use the results of two short-term tests done side-by-side (four inches apart) to decide whether to fix your home.
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 radon office can assist you in identifying a qualified tester.
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. The EPA recommends building new homes with radon-resistant features in high radon potential (Zone 1) areas. For more information, refer to EPA's Map of Radon Zones and other useful EPA documents on radon-resistant new construction, or visit www.epa.gov/radon/index.html Even if built radon-resistant, every new home should be tested for radon after occupancy. If you have a test result of 4 pCi/L or more, you can have a qualified mitigator easily add a vent fan to an existing passive system for about $300 and further reduce the radon level in your home.
Radon in Water
if you've tested the air... The radon in your home's indoor air can come from two sources, the soil or your water supply. Compared to radon entering the home through water, radon entering your home through the soil is usually a much larger risk.
The radon in your water supply poses an inhalation risk and an ingestion risk. Research has shown that your risk of lung cancer from breathing radon in air is much larger than your risk of stomach cancer from swallowing water with radon in it. Most of your risk from radon in water comes from radon released into the air when water is used for showering and other household purposes.
Radon in your home's water is not usually a problem when its source is surface water. A radon in water problem is more likely when its source is ground water, e.g. a private well or a public water supply system that uses ground water. Some public water systems treat their water to reduce radon levels before it is delivered to your home. If you are concerned that radon may be entering your home through the water and your water comes from a public water supply, contact your water supplier.
If you've tested your private well and have a radon in water problem, it can be easily fixed. Your home's water supply can be treated in two ways. Point-of-entry treatment can effectively remove radon from the water before it enters your home. Point-of-use treatment devices remove radon from your water at the tap, but only treat a small portion of the water you use and are not effective in reducing the risk from breathing radon released into the air from all water used in the home.
For more information, call EPA's Drinking Water Hotline at (800) 426-4791 or visit www.epa.gov/safewater/radon.html If your water comes from a private well, you can also contact your state radon office.
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, known as soil suction, 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 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 $800 to about $2,500. The cost is much less if a passive system was installed during construction.
how to lower the raon level in your home
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.
The Risk of Living With Radon
most homes can be fixed... house cutaway Lowering high radon levels requires technical knowledge and special skills. You should use a contractor who is trained to fix radon problems. A qualified contractor can study the radon problem in your home and help you pick the right treatment method.
Check with your state radon office for names of qualified or state certified radon contractors in your area. You can also contact private radon proficiency programs for lists of privately certified radon professionals in your area. For more information on private radon proficiency programs, visit www.epa.gov/radon/proficiency.html 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 are considering fixing your home's radon problem yourself, you should first contact your state radon office for guidance and assistance.
You should also test your home again after it is fixed to be sure that radon levels have been reduced. Most soil suction radon reduction systems include a monitor that will indicate whether the system is operating properly. In addition, it's a good idea to retest your home every two years to be sure radon levels remain low.

Note: This diagram is a composite view of several mitigation options. The typical mitigation system usually has only one pipe penetration through the basement floor; the pipe may also be installed on the outside of the house.

sneezing
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).
Smoking combined with radon is an especially serious health risk. Stop smoking and lower your radon level to reduce your lung cancer risk.
scientists are more certain about radon... 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
Some Common Myths About Radon [En Español]
RADON RISK IF YOU SMOKE [En Español]
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
evels below 2 pCi/L is difficult.)
0.4 pCi/L About 3 people could get lung cancer (Average outdoor radon level)
Note: If you are a former smoker, your risk may be lower.

RADON RISK IF YOU HAVE NEVER SMOKED [En Español]
Radon Level If 1,000 people who never 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)
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.
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 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 is difficult, time-consuming and expensive.
FACT: Radon testing is inexpensive and easy -- it should take only a little of your time.
MYTH: Radon testing devices are not reliable and are difficult to find.
FACT: Reliable testing devices are available through the mail, in hardware stores and other retail outlets. Call your state radon office for a list of radon device companies or visit our radon proficiency program web site for information on two privately run national radon proficiency programs.
MYTH: Homes with radon problems can't be fixed.
FACT: There are solutions to radon problems in homes. Thousands of homeowners have already fixed radon problems in their homes. Radon levels can be readily lowered for $500 to $2,500. Call your state radon office or visit our radon proficiency program web site for information on how to acquire the services of a qualified professional.
MYTH: Radon affects only certain kinds of homes.
FACT: House construction can affect radon levels. However, radon can be a problem in homes of all types: old homes, new homes, drafty homes, insulated homes, homes with basements and homes without basements.
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 problem.
FACT: It's 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 their 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 you find high levels and your water comes from 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 homes where radon problems have been discovered.
FACT: Where radon problems have been fixed, home sales have not been blocked or frustrated. The added protection is some times a good selling point.
MYTH: I've lived in my home for so long, it doesn't make sense to take action now.
FACT: You will reduce your risk of lung cancer when you reduce radon levels, even if you've lived with a radon problem for a long time.
MYTH: Short-term tests cannot be used for making a decision about whether to fix your home.
FACT: A short-term test, followed by a second short-term test may be used to decide whether to fix your home. However, the closer the average of your two short-term tests is to 4 pCi/L, the less certain you can be about whether your year-round average is above or below that level. Keep in mind that radon levels below 4 pCi/L still pose some risk. Radon levels can be reduced in some homes to 2 pCi/L or below.
State and Regional Radon and Indoor Air Quality Contacts
[www.epa.gov/iaq/whereyoulive.html]
National Radon Hotline:
1 800/SOS-RADON
For other Indoor Air Hotlines: [www.epa.gov/iaq/iaqxline.html]
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 [En Español]
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/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 or visit our publications site 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."
How to Order Publications from EPA
IAQ INFO
P.O. Box 37133, Washington, DC 20013-7133
1-800-438-4318/703-356-4020
(fax) 703-356-5386
iaqinfo@aol.com
or, you can order this publication directly via EPA's National Service Center for Environmental Publications (NSCEP) (http://www.epa.gov/ncepihom/). web site. Your publication requests can also be mailed, called or faxed directly to:
U.S. Environmental Protection Agency
National Center for Environmental Publications (NSCEP)
P.O. Box 42419
Cincinnati, OH 42419
1-800-490-9198/(513) 489-8695 (fax)

national information: Indoor Air Topics

If you have further questions about Radon, please call your State Radon Contact
or,
the National Radon Information Line at: 1-800-SOS-RADON
[1-800-767-7236],
or,
(if you have tested your home) The Radon FIX-IT Program at:
1-800-644-6999 www.radonfixit.org
To get a discounted Radon Test Kit
EPA's Radiation Protection Program page on Radon

Lead - How Lead Affects the Way We Live & Breathe
Published by the US EPA
Office of Air Quality Planning & Standards
November 2000
Levels of the pollutant - "lead" - in the air have decreased dramatically since 1978, primarily due to reductions in emissions from cars and trucks. Today, metal processing plants are generally responsible for most of the lead in the air.
urban area Table of Contents
Lead: What is it? Where does it come from?
Chief Causes for Concern
Health and Environmental Impacts of Lead
EPA's Efforts to Reduce Lead
USEPA Offices