What is vapor recovery in relation to USTs?

Vapor recovery refers specifically to the process designed to capture and control the vapors released during the transfer of fuel to and from underground storage tanks (USTs). When fuel is pumped into a tank, the space above the liquid fuel fills with vapors that can be harmful if released into the atmosphere. The vapor recovery system collects these vapors and either returns them to the storage tank or processes them to prevent them from being released, thereby reducing air pollution and improving environmental safety.

This process plays a critical role in minimizing emissions that can contribute to air quality issues, making it an essential aspect of regulatory compliance for facilities that handle fuels. The other options, while related to USTs, do not pertain to the specific function of capturing vapors during fuel transfer. For instance, refilling tanks, cleaning contaminated soil, and monitoring tank pressure all serve different operational and safety purposes within the context of UST management, but they do not capture the essence of vapor recovery.