Which UST component is specifically designed to prevent overfilling?

The overfill protection device is specifically designed to prevent overfilling of underground storage tanks. This component plays a crucial role in environmental safety by ensuring that the tank does not exceed its capacity during filling operations. When a tank is being filled, the overfill protection device engages to alert the operator or automatically shut off the flow of fuel when a predetermined level is reached. This helps to minimize the risk of spills, leaks, and potential contamination of surrounding soil and groundwater, which are serious environmental concerns associated with UST systems.

Other components, while important to the overall functionality and safety of the UST system, do not have the same primary function. For instance, the leak detection system is designed to identify any leaks that may occur within the tank or its piping and does not prevent overfilling directly. The ventilating system is essential for managing pressure within the tank and ensuring that vapors do not accumulate but does not address overfilling specifically. Similarly, monitoring wells are utilized to track groundwater levels and contamination but do not play a role in the actual filling process of the UST. Thus, the overfill protection device stands out as the dedicated component for managing and preventing overfilling.