2025 Class A/B Operator UST Practice Test – Comprehensive Exam Prep

Stage I vapor recovery is related to the delivery process of fuel to underground storage tanks (USTs). This system is designed to control emissions of volatile organic compounds (VOCs) that occur when fuel is delivered from a tank truck to the UST. During the transfer, vapors that would otherwise escape into the atmosphere are captured and returned to the tank truck or directed back into the UST.

This process helps to minimize air pollution and ensures compliance with environmental regulations. It addresses emissions occurring when the tank is filled, which is critical during fuel deliveries. Stage II, on the other hand, pertains to vapor recovery during the dispensing process at the fueling station itself, capturing vapors produced when a vehicle is being fueled.

Active and passive refer to systems in a broader context and do not specifically denote the recovery that occurs during the delivery phase. Active systems typically involve powered equipment to facilitate vapor recovery, while passive systems rely on the vacuum created during the fuel transfer or other natural physical mechanisms to control emissions. Therefore, Stage I is the correct answer as it pertains directly to the vapor recovery associated with the delivery of fuel to USTs.