How do chemicals from the groundwater get into my home or building?
Vapor intrusion, the process by which chemical vapors enter a home or building, can happen when it is located above or near an area of contaminated groundwater. If the chemicals in the groundwater are found at the water table, they can vaporize and move up into homes and buildings through gaps, cracks, or holes in the foundation or basement floor. Whether or not they enter the home or building depends on a lot of things, including the atmospheric pressure inside the home or building, the outside temperature, the type of heating system in the location etc. If the conditions are right, vapors can enter the home or building.
How do I know if I have vapors in my home or building?
If you live near an area of shallow groundwater contamination, the Air Force will sample the air in your home or building, if requested. Tests are only done during the heating season (October through March), as that is when vapor intrusion is most likely to occur. The Air Force will provide you with a copy of the lab report, generally eight weeks after the sampling is completed. If vapors are present in your home or building, an Air Force representative will call with the results over the phone, as well as in writing.
How much will testing cost me?
Testing the air costs you nothing. The Air Force covers all costs associated with the testing and any subsequent mitigation efforts.
What happens if vapors are found in my home or building?
If the sample comes back as positive, above our action level, and is confirmed as vapor intrusion from the groundwater, the Air Force will recommend the installation of a Vapor Intrusion Mitigation System (VIMS). These systems consist of a pipe that is installed through your basement floor. A small fan, installed in the attic or on the outside of the home or building, is attached to the pipe, which sucks the vapors from beneath the foundation, up through the pipe and out of the house or building. Radon remediation uses a similar system. More than 125 VIMS have been installed with great success around the base. All costs associated with the VIMS will be paid by the Air Force.
If vapors are detected, but below the action level, the Air Force would continue to monitor the levels in the home on an annual basis. If at some point vapors are found above the action level, a VIMS would be offered.
What if the sample doesn’t detect vapors in my home or building?
If vapors are not detected in the sample, then it is unlikely vapor intrusion is occurring in your home and sampling will no longer be needed or offered.
Do the vapors pose risk to people living in the home?
Protecting the health of residents is our top priority. When we do find vapors in homes, the concentrations are usually very low and while most people will not experience adverse health effects, some sensitive populations may be affected by short-term exposure to the chemicals. The action levels have been set with this in mind. This is why we test the air and take measures to prevent vapors from entering the home.
Our objective is to ensure that vapor levels do not exceed the action levels, which have been developed in conjunction with the Utah Department of Environmental Quality and the U.S. Environmental Protection Agency. We have used the latest research to set these levels, which have extra layers of safety built in to ensure protection of the most sensitive populations, such as children and the elderly. If the levels detected from the groundwater exceed the action level, we can install a system (VIMS) to reduce those levels to below the action level.
How do you know if vapors are coming from inside the home or from the groundwater?
The sampling device we place in the home or building only tells us if vapors are present in the air inside the home. It does not tell us the source of those vapors. If vapors are detected in the initial sample above an action level, the Air Force will conduct additional testing to look for inside sources. If none are identified, vapor intrusion is the likely source and, if above an action level, a VIMS would be offered to the resident. If an inside source is identified, we ask the resident to remove the item and then we test again.
If the inside sources are removed and follow-up tests are still positive, the sampling team may conduct a pressure test to artificially create optimal vapor intrusion conditions. If those tests produce a positive result, then it’s likely that the groundwater is the source of the vapors in the home.
It’s important to note that a VIMS will not be effective if an inside source is present. A VIMS only pulls contaminant vapors from beneath the home. If a source is inside, it will continue to be found in the air until it is removed.
What if I don’t want indoor air sampling?
Sampling is completely voluntary and you are not required to have your home or building tested. We only test homes or buildings at the request of the resident or owner. It is highly recommended that you have at least one sample conducted in your home or building to ensure you are not being exposed to harmful levels of chemical vapors.
I’ve been sampled in the past. Do I need to be sampled again?
That depends on the type of sample taken. If you have been sampled using one of the large, silver canisters, your sample was for one 24-hour period. Research has shown, however, that vapor intrusion occurs only under certain conditions that can vary from day-to-day. If your sample was taken on an unfavorable day, it may miss vapor intrusion that could be occurring on other more favorable days.
In 2015, the Air Force replaced the 24-hour sample canisters with new devices that are left in a home or building for about 26 days. These long-duration samplers allow for a continuous monitoring of the air during both favorable and unfavorable conditions. If vapor intrusion is occurring, these devices have a better chance of finding it. If there is no vapor intrusion, these devices will report that with much greater certainty than the 24-hour canisters.
If you’ve only been sampled once or twice before using the old sampling method the results may not sufficiently guarantee that vapor intrusion is not occurring in your home. We recommend having your home sampled using the new long-duration sampling devices.
If you’ve been sampled with one of the new sampling devices and it shows vapor intrusion is not occurring, your location will require no further sampling.
What if I don’t have a basement?
We still recommend having your home tested. We will place the sampling device in the lowest livable space of your home.
Is my drinking water safe?
Yes. You are most likely connected to city water. The city obtains its drinking water from deep aquifers or mountain reservoirs. Your city regularly tests its water to ensure it is safe. If you are drinking city water, you are not drinking contaminated water. For information about your drinking water, contact your city’s public works office.