What does "UST system" encompass?

The term "UST system" stands for "Underground Storage Tank system," which specifically includes the tank itself along with the associated piping and pumps used for the storage and transfer of petroleum products or hazardous substances. This definition is critical because it underscores the components that are directly involved in the containment and management of these substances.

The tank is the primary component, designed to hold the materials, while the associated piping and pumps play crucial roles in the transfer and flow of liquid in and out of the tank. Understanding this definition is essential for compliance with regulations and ensuring proper management of USTs, as it highlights the complete system necessary for safe handling.

The other choices are too narrow or not inclusive of what a UST system truly encompasses. For instance, while storage space for hazardous materials is related, it does not specifically refer to the tank and its operational components. Similarly, monitoring equipment, while important for safety and compliance monitoring, is just one aspect of the broader system and does not represent the entire UST configuration. Lastly, the physical structure of the storage facility may refer to the building around the tank which is not part of the UST system itself. Hence, the correct definition emphasizes the integral components directly involved in the operation and maintenance of the UST