What is an essential safety measure before refueling a boat?

Before refueling a boat, it is crucial to remove all passengers from the boat to ensure everyone’s safety. This action minimizes the risk of accidents and allows the operator to focus on the refueling process without distraction. By keeping the boat free from individuals, the chances of spillage, ignition of fumes, or other hazardous incidents are greatly reduced.

The other actions mentioned, while possibly having some relevance under different circumstances, do not directly enhance safety during refueling. Turning on electronic devices could create sparks or unnecessary distractions. Filling the fuel tank to the brim might cause overflow, leading to potential hazards. Opening windows for ventilation might help in some scenarios but is typically less critical than ensuring that there are no passengers onboard.