When fueling a placarded vehicle, someone must always be ____.

When fueling a placarded vehicle, it is essential that someone is at the nozzle, controlling the fuel flow. This requirement is crucial for safety reasons. Having an individual present at the nozzle ensures that they can immediately address any potential hazards that may arise during the fueling process, such as spills, leaks, or unexpected ignition sources. Maintaining direct control over the fuel flow allows for prompt intervention and helps minimize the risk of accidents involving hazardous materials.

Monitoring the fuel gauge, being inside the vehicle, or searching for a receipt does not provide the same level of safety accountability as being at the nozzle. These actions do not allow for immediate responsiveness in case something goes wrong during fueling. Therefore, having direct oversight at the nozzle is a critical component of safe fueling practices for vehicles transporting hazardous materials.