IMO Resolution MSC.255(84) — the Casualty Investigation Code — sets the international framework for safety investigations into marine casualties and incidents. Mandatory under SOLAS XI-1 Reg. 6 since January 2010. The Code distinguishes between 'safety investigation' (lesson-learning, confidential statements) and other proceedings (criminal, civil, administrative) which run on separate evidentiary tracks.
Casualty categories
Very serious marine casualty — loss of life, total loss of ship, or severe pollution. Mandatory investigation by the flag state and notification to IMO GISIS.
Serious marine casualty — substantial damage, immobilisation of main propulsion or other propulsion that prevents service; significant injuries or pollution. Investigation expected.
Less-serious marine casualty — discretionary investigation by flag state.
Marine incident — event or sequence of events that could have endangered ship, crew, environment, or property. Investigation discretionary; near-miss reporting encouraged.
Master's first actions
1. Ensure safety of crew, vessel, environment in that order.
2. Notify the company / DPA. The DPA notifies flag state, class, port state where casualty is in territorial waters, and the P&I correspondent.
3. Preserve VDR/S-VDR — operate save function or de-power the recorder; the data integrity must be maintained.
4. Preserve all evidence: ECDIS, CCTV, OLB, ENG-room log, alarm logs, charts, weather data, deck and engine work permits, drug & alcohol test results.
5. Open a casualty file: photographs of damage / environment, witness list, sequence of events while still fresh.
6. Statements: encourage crew to make their statements truthfully to the safety investigator. Make a separate, more cautious approach to any criminal-track investigator after consulting the P&I correspondent.
7. Continue to log events as they unfold in the OLB until the situation is stabilised.
National investigation bodies
MAIB (United Kingdom) — Marine Accident Investigation Branch; investigates UK-flag casualties worldwide and others in UK waters.
NTSB (USA) — National Transportation Safety Board; covers vessels in US waters and US-flag worldwide.
ATSB (Australia) — Australian Transport Safety Bureau.
TSB (Canada) — Transportation Safety Board of Canada.
BSU (Germany) — Bundesstelle für Seeunfalluntersuchung.
BMA / Liberia / RMI / Panama — large flag administrations; commission independent investigators (often class society or specialist firms) when their flag is involved.
AIBN Norway, DAIB Denmark, Onderzoeksraad Netherlands — strong investigative bodies often called in for cross-border casualties.
Statement protections
Casualty Investigation Code Section 23 makes statements given to safety investigators confidential and inadmissible in civil / criminal / administrative proceedings against the seafarer, except where a competent authority specifically determines that the public interest of disclosure outweighs the public interest in encouraging future testimony. This protection applies to the safety-investigation track only. A separate statement to a port-state criminal investigator (e.g. local police or coast-guard prosecutor) is on a different track — request P&I-correspondent and union-rep involvement before speaking.