Why the need for this fact sheet?
The issue of vapor intrusion (VI) is being raised more and more
in communities located near hazardous waste cleanup sites
across the country. In response to this interest, EPA has devel-
oped this fact sheet to answer some of the most commonly
asked questions.
What is vapor intrusion?
When chemicals or petroleum products are spilled on the
ground or leak from underground storage tanks, they can give
off gases, or vapors, that can seep inside buildings. The vapors
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.
What vapors might be entering my home, and how would they
get there?
•	Common examples of vapors are from gasoline or diesel
fuel, dry cleaning solvents, and industrial degreasers.
•	Common sources are petroleum leaks from underground
storage tanks.
•	This type is usually associated with a gasoline odor.
•	Solvents from other commercial and industrial sites are
usually odor-free.
•	Vapors also are given off by common household products,
which are a more likely source of indoor air problems than
leaks or spills. Examples include:
• • paints, paint strippers or thinners • cigarette smoke
moth balls • air fresheners • new carpeting and
furniture • solvents • stored fuel • dry-cleaned
clothing
What are the health concerns with vapor intrusion?
•	Health effects vary, based on person, exposure and chemi-
cal type.
•	For more information on the health risks of Vapor Intrusion
please visit the Agency for Toxic Substance and Disease
Registry (ATSDR) Vapor Intrusion Health Risks Evaluation at:
http://go.usa.gov/Yntd
How is vapor intrusion discovered?
•	A variety of samples are collected near a contaminated site
first.
•	If no contamination is found near a site, we know there is no
possibility of vapors moving outward.
•	If contamination is found near a site, depending on the type,
the search may be widened to include samples closer to, or
on your property.
•	A summa canister (Figure 1) collects samples from outside air
and indoor air for a determined period of time. A summa
canister is approximately the size of a basketball.
•	Also, samples are taken from under the home's foundation;
these are called slab, or sub-slab samples.
What happens if a problem is found?
•	The most common solution is to install a radon mitigation
(reduction) system (Figure 2), also know as an active sub-
slab depressurization system (SSDS). An SSDS essentially pre-
vents vapors beneath a slab from entering a building or
home.
What can I do to improve indoor air quality?
Consider these tips to improve indoor air quality in your home:
Don't buy more chemicals than you need.
Store unused chemicals in appropriate containers in well-
ventilated areas.
Don't make your home too air tight. Fresh air helps prevent
chemical build-up and mold growth.
Fix all 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.
•	Install carbon monoxide detectors.
The EPA is dedicated to providing you
with timely and accurate information
about our work. If you have any questions
or concerns, please do not hesitate to
contact us.
Information Links
Agency for Toxic Substance and Disease
Registry (ATSDR) Vapor Intrusion
Health Risks Information:
http://go.usa.gov/Yntd
EPA Vapor Intrusion Website:
http://go.usa.gov/v5K
EPA Superfund Vapor Intrusion FAQs:
http://go.usa.gov/v57
Dublin TCE Superfund Site Website:
http://go.usa.gov/KqmR
Figure 1

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Contact Us!
Greg Voigt
Remedial Project Manager
215-814-5737
voight.greg@epa.gov
Larry Brown
Community Involvement
Coordinator
215-814-5527
brown.larry@epa.gov
Superfund Hotline
1-800-424-9346
U.S. EPA Region III
Public Reading Room
1650 Arch Street-6th Floor
Philadelphia, PA 19103
(215)-814-3157
Hours: Monday-Friday
8:30 a.m. to 4:30 p.m.
Dublin TCE Superfund Site
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Conceptual Diagram of Vapor Intrusion
U.S Environmental Protection Agency, Region 3
Serving Delaware, Maryland, Pennsylvania, Virginia, West Virginia, and the District Of Columbia
U.S. ENVIRONMENTAL PROTECTION AGENCY
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