# What You Should Know About Vapor Intrusion

EPA has developed this fact sheet to answer some of the most commonly asked questions about an important health issue called vapor intrusion. Vapors and gases from contaminated groundwater and soil have the potential to seep into indoor spaces and cause health problems.



## W hat 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 get inside buildings. Common products that can cause vapor intrusion are gasoline or diesel fuel, dry cleaning solvents and industrial de

- greasers. 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. Some vapors such as those associated with petroleum products ha ve a gasoline odor, others are odor

- free.


## Can vapors in my home come from household sources? Common household products can be a source of indoor air problems. Vapors and gases can come from : paints; paint strippers or thinners; moth balls; new carpeting and furniture; stored fuel; air fresheners; cleaning products; dry cleaned clothing and even cigarette smoke.


## What are the health concerns related to vapor intrusion? When vapor intrusion does occur, the health risk will vary based on the type of chemica ls

, the levels of the chemical found, the length of exposure and the health of exposed individuals. Some people may experience eye and respiratory irritation, headaches and/or nausea . These symptoms are temporary and should go away when the vapors are ad dressed. Low

- level chemical exposures over many years may raise the lifetime risk of cancer or chronic disease.


## How is vapor intrusion discovered? Samples of gas in the soil or groundwater are first collected near a contaminated site. If no contaminatio n is found near a site, then vapor intrusion should not be a problem. If contamination is found

, depending on the type, the search may be widened to include samples closer to or on individual properties. The next step is to take vapor samples from the so il under the home ’ s foundation; these are called slab, or sub

- slab samples. EPA does not generally recommend indoor air sampling before slab or sub

- slab sampling, because indoor air quality varies widely day to day. Also, household products may interfere with sampling results.


## What happens if a problem is found? The most common solution is to install systems often used to reduce naturally occurring radon that seeps into homes in some geographic areas. T he se systems , called radon mitigation systems

, rem ove soil vapors from below basements or foundations before they enter homes. Vapors are vented outside of the homes where they become dispersed and harmless. These systems use minimal electricity and do not affect heating and cooling efficiency. They al so prevent radon from entering homes

– an added health benefit especially in radon prone areas. Once the source of the vapors is eliminated, the systems should no longer be needed.

## What ca n I do to improve indoor air quality?

**•** Don’t buy more chemical s 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 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 or you can call the Radon Hotline at 800

- 458

- 1158 in New York State, or 800

- 648

- 0394 in New Jersey.

**•** Install carbon mo noxide detectors in your home. They are available at hardware and home improvement stores.



## For more information:

**•** For health related questions regarding vapor intrusion, contact your local health department or the federal Agency for Toxic Substances and Disease Registry at: 1

- 888

- 422

- 8737 or visit their Web site at www.atdsr.cdc.gov

**•** For more detailed information on EPA’s vapor intrusion sampling, visit the EPA’s Web site at: www.epa.gov/correctiveaction/eis/vapor/guidance.pdf

**•** For more information on indoor air quality, visit EPA’s Web site at: www.epa.gov/air/topics/comoria.h tml or call the indoor air Quality Information hotline at 1

- 800

- 438

- 4318 

### Vapor Intrusion: Tightly seal common household products after use and seal them in an area that is well ventilated to avoid the release of vapors



## Sub

- slab mitigation system: This system draws radon and other vapors out of the soil and vents them outside