How do you fight a fire in undeclared IMDG cargo?

flowchart TD
  A["Fire in dangerous goods"] --> B{"Cargo declared and identified?"}
  B -->|Yes| C["Apply that cargo's EmS fire schedule (F-A to F-H)"]
  B -->|No or mis-declared| D["Assume the worst: general fire schedule F-A"]
  D --> E["Alarm, muster, breathing apparatus, evacuate and control access"]
  E --> F["Boundary cooling with water spray, to windward; no unknown medium on the cargo"]
  F --> G["Identify the cargo from manifest, markings, DPA; switch to its schedule"]

• Framework: emergency response information must be immediately available (IMDG §5.4.3.2.1); the EmS Guide (MSC.1/Circ.1025) gives each cargo a fire schedule F-A to F-H and a spillage schedule S-A to S-Z.
• Undeclared: no reliable hazard information, so treat it as the worst case and apply the general fire schedule ALFA (F-A).
• Actions: raise the alarm and muster; breathing apparatus and protective clothing; evacuate and control access; boundary cooling with water spray from a protected position to windward.
• Trap: water is not assumed safe, it reacts violently with dangerous-when-wet class 4.3 substances; cooling only for compressed gases.
• Identify and escalate: manifest, booking, stowage position, markings, shore response and the DPA; switch to the specific schedule once known; close ventilation, consider fixed CO2, manage the heading.
• Offence: mis-declaration breaches the IMDG Code and SOLAS chapter VII; casualty report, s.231 notification for an Indian ship, documents secured as evidence.
• As Chief Engineer: fire main and pumps, emergency fire pump, fixed installations and boundary-cooling supply; people first, contain and cool, identify, then fight correctly.