What does the "interstitial monitor" refer to in relation to secondary containment?

The term "interstitial monitor" specifically refers to a device designed to detect leaks within the secondary containment of underground storage tanks (USTs). Secondary containment systems are crucial for environmental protection, as they prevent product spills or leaks from escaping into the surrounding soil and groundwater. The interstitial monitor operates by detecting any liquid that may accumulate in the space between the primary tank and the secondary containment barrier. This monitoring is vital because it provides an early warning of potential leaks, allowing for timely remedial action, which helps safeguard public health and the environment.

While other options describe different functions—such as measuring temperature or gauging product levels—they do not directly relate to the primary role of an interstitial monitor, which focuses exclusively on leak detection within the context of secondary containment systems.