If an unknown fluid is being discharged overboard, who should you contact?

The correct choice is to contact CCS (Central Control Station) and call "CEASE ALL PUMPING." When an unknown fluid is being discharged overboard, it is crucial to immediately halt the discharge to prevent environmental contamination and comply with safety protocols. The CCS is responsible for monitoring and managing ship operations and will coordinate the response and investigation of such incidents.

Notifying CCS allows for prompt evaluation of the situation, and essential actions can be taken to mitigate any potential hazards. In addition, a "CEASE ALL PUMPING" command will help ensure that all systems responsible for the discharge are shut down, thereby preventing further release of the unknown substance into the water.

This swift response is essential for ensuring safety and environmental protection, which is a primary concern when dealing with potentially hazardous materials.