What is the first action to take if there is a major leak on the FOP's?

In the event of a major leak on the Fuel Oil Purifier (FOP), toggling switches outside the space is a crucial first action because it can help to immediately shut off power or activate emergency systems to mitigate the leak's impact. This response prioritizes the safety of personnel and allows for quicker response measures to control the situation.

Taking immediate action to deactivate equipment can prevent further spillage or ignition of flammable substances. It contributes to safeguarding the crew and the vessel, providing the opportunity to assess the source and severity of the leak while minimizing potential hazards.

Calling emergency services or evacuating the area are indeed critical steps that may follow after initial controls are activated, but they come after securing the immediate environment and reducing further risk. Shutting down all machinery is also an important consideration, but doing so through toggling switches provides a more controlled and immediate way to address the leak without compromising safety further.