During bunkering, when is the most critical time regarding accidental oil pollution?

The final topping off is indeed the most critical time regarding accidental oil pollution during bunkering operations. This phase occurs as the tank is nearly full and precise attention is required to manage the flow of fuel. The risk of spillage or overflow is highest at this point because the personnel need to closely monitor the filling process to prevent overfilling.

If an overflow were to occur, it could lead to significant pollution in the surrounding water, thus emphasizing the importance of vigilance and adherence to safety protocols during this stage. Moreover, as fuel is added to the tank, the volume and pressure increase, making any miscalculation or equipment failure potentially disastrous.

While other options present situations that require caution—like disconnecting hoses or blowing them down—they typically carry lower immediate risk compared to the critical state of final topping off. During those actions, there are generally procedures in place aimed at preventing spills, such as ensuring that valves are closed properly before disconnection. Safety protocols are always heightened during the final topping off phase to mitigate the greater potential for environmental impact.