*>EPA
United States
Environmental Protectior
Agency
What you can do to improve
indoor air quality
•	Don't buy more chemicals than you
need.
•	Store unused chemicals in
appropriate tightly sealed
containers.
•	Don't make your home too air-tight.
Fresh air helps prevent chemical
build-up and mold growth.
•	Fix leaks promptly, as well as other
moisture problems that encourage
mold.
•	Check all appliances and fireplaces
annually.
•	Test your home for radon. Test kits
are available at hardware and home
improvement stores or you can call
the Radon Hotline at 800-767-7236
(800-SOSRADGN).
•	Install carbon monoxide detectors in
your home. They are available at
hardware and home improvement
stores.
For more information
For questions on how vapor intrusion
affects your health, contact your local
health department or the federal
Agency for Toxic Substances and
Disease Registry at 888-422-8737, or
visit www.atsdr.cdc.gov.
For detailed EPA information on
vapor intrusion, visit
www.epa.gov/oswer/vaporintrusion.
For more information on indoor air
quality, visit www.epa.gov/iaq.
You may also call EPA Region 5 at
800-621-8431, 8:30 a.m. to 4:30 p.m.
(Central), weekdays.
What You Should Know About
the Problem of Vapor Intrusion
EPA Superfund Division
Chicago, Illinois
January 2012
Vapor Intrusion into Indoor Air
Indoor Air
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Soil Gas
( I I t I I I I t I
®	Chemical Vapor Migration
Soil
Contamination
Groundwater
Contamination
This diagram shows how vapors can rise up through The soil and into your home.
Vapors and gases from contaminated ground water and soil have the
potential to seep into indoor spaces and cause health problems. The U.S.
Environmental Protection Agency wants you to know how to deal with
vapor intrusion in your home.
What is vapor intrusion?
When chemicals or petroleum products are spilled or leak from
underground storage tanks, they can give off gases or vapors that can get
inside buildings. Common products that can cause vapor intrusion are
gasoline or diesel fuel, dry cleaning solvents and industrial degreasers. The
vapors can move through the soil and seep through cracks in basements,
foundations, sewer lines and other openings.
Vapor intrusion is a concern because vapors can build up to a point where
the health of residents or workers in those buildings could be at risk. Some
vapors from petroleum products have a gasoline odor, others are odor-free.
Common household items can give off vapors
Common household products can be a source of indoor air problems.
Vapors and gases can come from paint, paint strippers or thinners, moth
balls, new carpeting and furniture, stored fuel, air fresheners, cleaning
products, dry-cleaned clothing and cigarette smoke.

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Vapor intrusion may affect your health
Health risks vary based on the type and amount of
chemicals. How healthy you are and how long you are
exposed are also factors. Some people may experience
eye and respiratory irritation, headaches or nausea.
These symptoms are temporary and should go away
when the vapors are vented. Low-level chemical
exposures over many years, however, may raise your
lifetime risk of cancer or chronic disease.
Steps in the study of vapor intrusion
EPA first takes samples of gas in the soil and ground
water near a site with known contamination. If we
don't find the type of contamination that can turn into a
gas - known as "volatile" - then vapor intrusion should
not be a problem.
If we find volatile contamination, we may widen the
search to include sampling closer to or on individual
properties. The next step is to take vapor samples from
the soil under building foundations. These are called
"sub-slab soir gas samples.
The results of these samples will tell EPA if indoor air
samples are needed. The indoor air samples will tell us
if there are vapors in the indoor air. The samples will
also show if the vapors pose a health risk, or if they are
at levels normally present in most buildings.
An example of a system that draws radon and other vapors out of
the soil and vents them outside. It's known as a "sub-slab mitigation
system."
EPA does not generally recommend indoor air
sampling before sub-slab sampling because indoor air
quality varies widely day to day. Also, household
products may interfere with sampling results.
Finally, we will determine if there is enough of a
problem to take action. Environmental law and EPA
regulations tell us when we need to do something to
protect your family's health.
If EPA finds a problem
The most common solution is to install systems often
used to reduce naturally occurring radon that seeps into
homes in some geographic areas. These systems
remove soil vapors from below basements or
foundations before they enter homes.
Vapors are vented into the outside air where they
become dispersed and harmless. These systems use
minimal electricity and do not affect heating and
cooling efficiency. Once the source of the vapors is
eliminated, the systems should no longer be needed.
One way to keep harmful vapors crnt of your home is to make sure
common household products, especially chemical- and petroleum-
based products, are tightly sealed and properly stored in a well-
ventilated area.
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