Which scenario does not require cargo transfer operations on a tank vessel to be stopped?

In the context of tanker operations, safety protocols dictate that certain scenarios necessitate the immediate cessation of cargo transfer operations to mitigate risk and ensure crew and environmental safety. Stopping operations is crucial during a fire on the dock or on a nearby vessel, as this could pose significant danger, potentially leading to explosions or further fires. Similarly, an electrical storm in the vicinity can pose a serious risk, especially with the presence of flammable cargo, as lightning could ignite vapors or cause electrical failures.

When a large, fresh oil spill is discovered adjacent to the side of the tanker, it indicates an immediate environmental hazard that could be exacerbated by the transfer of cargo, thus requiring an urgent halt to ensure proper response to the spill and prevent further contamination.

In contrast, the scenario involving a tug coming alongside while the tanker is loading grade D and E cargoes does not inherently require the stoppage of operations. While safety assessments and protocols should certainly be followed, the presence of a tug does not present the same level of immediate risk as the other scenarios mentioned. The cargoes themselves, grades D and E, specified in relation to their flash points and properties, may not necessitate an immediate halt unless specific safety procedures or operational protocols are violated.