1. In the afternoon of 25th May 1999, the HK licensed Dumb Steel Lighter " Wing On No.1" moored alongside Berth 13 of Stonecutters Island Public Cargo Working Area was shifting freight containers on board by her own cargo handling gear. At about 1530 hours, a 40 foot hicube container laden with dismantled parts of second-hand motorcycles was lifted by the derrick after a sailor had hooked all 4 lifting slings to the container. Another sailor was stationed near the port hatch coaming to help the positioning of the container. A tally clerk was standing near the hatch coaming on the starboard side. The container was lifted with the sailor who had put on slings staying on its roof. After it was lifted one tier up and about 0.3 metre from landing onto the second tier container in the next forward row, the lowering was halted because the container swung and slightly struck the top surface of the container on which it was to be landed. At this instant, the container exploded. Two explosions occurred, one following the other.

2. The explosions ruptured the container and the motorcycle parts burst into flames ( see Appendix A ). The blast of the explosions killed the tally clerk working on the lighter and seriously injured one sailor while throwing him from the roof of the container into the sea. The sailor helping to position the container was slightly injured while jumping overboard to escape. The Fire Service Department was called to the scene and put out the fire at about 1730 hours.

B. Findings

1. The most possible cause of the explosion was the accumulation of hydrocarbon vapour in the container which was ignited by spark generated by either metallic contacts between the unsecured motorcycle parts or short circuit of the batteries. The accumulation was due to the uncleaned fuel tanks of motorcycles containing residue of volatile hydrocarbon based substance and residual fuel in the engine assemblies. As a result, flammable vapour was given off through the vent valve of the fuel tanks and the open end of the fuel supply hose as well as vent holes of the carburettors allowing the vapour of the residual fuel to accumulate. The container was not venting the flammable vapour even though ventilators were provided at each corners. This facility was not intended for dispersing of accumulated vapour. The hydrocarbon vapour which might be in small amounts was trapped in the container.

2. The principal cause of this accidents was due to the non-observance of the safety guidelines for transport of motor vehicles/cycles. As a result, residual fuel from the dismantled motorcycles parts vaporised and accumulated inside the container.

3. The investigation also revealed that the transportation parties were not in possession of documentation detailing the content of the containers. The lack of documentation for containers would not only make it difficult to identify any potentially hazardous cargo carried, but also make it impossible to assess its loading effect on the stability of the vessel.

4. The investigation also showed that the sailor who sustained serious injury from the explosions had been staying on the roof of the lifting container and the No.1 lighterman failed to react to such unsafe practice by the sailor. Both the sailor and the No.1 lighterman were not following the Shipboard Cargo Handling Safety Guide issued by Marine Department in 1995.

C. The Lessons

1. Non compliance of the safety guidelines for the transport of motor vehicles/cycles is considered the principle cause of this accident. Had the guidelines been followed, there would have been no uncleaned fuel tanks of motorcycles containing residue of volatile hydrocarbon based substance and residual fuel in the engine assemblies, and as a result no accumulation of hydrocarbon vapour in the container.

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