Program Overview

In a number of communities surrounding Hill AFB, chemicals from the base have contaminated areas of shallow groundwater. The groundwater is not used for drinking or other household uses. It is possible, however, for chemicals to evaporate from the groundwater and move into homes. (Click here to see how vapors move into homes.) This process is known as vapor intrusion.

Vapor intrusion doesn’t happen in every home. Hill AFB's Indoor Air Sampling Program focuses on testing homes 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. 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.

Over the last several years, Hill has tested the air in approximately 2,000 homes in communities surrounding the base affected by groundwater contamination. Less than 10 percent of homes tested have had vapor levels above an action level. A vast majority of those homes, however, were tested using a method that could have missed vapor intrusion. Click here for more information about how testing methods have changed to more accurately determine if vapor intrusion is occurring.