In seven communities surrounding Hill AFB, chemicals from historical practices at the base have contaminated areas of shallow groundwater. Since the groundwater is not used for drinking or other household uses, the only way for the public to be exposed to the chemicals in the groundwater is through a process known as vapor intrusion. Vapor intrusion occurs when chemicals from the groundwater evaporate and move into homes or businesses within the affected area. (Click here to see how vapors may move into homes or businesses.)
Vapor intrusion doesn’t happen in every home or business within the affected area. Hill AFB's Indoor Air Sampling Program focuses on testing locations most likely to have vapor intrusion—those above or close to areas of shallow groundwater contamination. In cooperation with state and federal regulators, the Air Force has established contaminant levels at which it will recommend taking action to prevent vapors from the groundwater from entering the home or business. These levels are called Risk-Based Action Levels, or RBALs. (Click here for more information about RBALs.) All sampling and mitigation actions will be done at no cost to the resident.
Since 2001, Hill has tested the air in more than 2,300 locations in communities surrounding the base affected by groundwater contamination. Less than 10 percent of homes and businesses tested have had vapor levels above an action level. A vast majority of those locations, however, were tested using a 24-hour method that could have missed vapor intrusion. Testing is now done with a 26-day sampler to ensure more accurate results. (Click here for more information about how testing methods have changed to more accurately determine if vapor intrusion is occurring.)
The maps linked below show the areas where air sampling is offered to homeowners, tenants, property owners and businesses as outlined by an orange line. Residences, businesses and schools within or touching the orange line are eligible for testing.
Frequently Asked Questions
EPA's Vapor Intrusion Website
ToxFAQs (Agency for Toxic Substances and Disease Registry's Toxic Substances Portal)
The Air Force has tested the air in more than 2,300 homes since 2001. Testing is done during the heating season (October through March). Research has shown that this is the best time to detect vapor intrusion.
How the air is tested
Can household products trigger a detection?
Sampling method fact sheet
Preparing your home for testing
Click here to see how vapors can enter homes.
Indoor Air Program Manager
75th Air Base Wing Public Affairs
U.S. Environmental Protection Agency, Region 8
(800) 227-8917 ext. 312-6666
Utah Department of Environmental Quality
Craig Barnitz (Project Manager)
David Allison (Public Involvement)