Singapore’s Transport Safety Investigation Bureau has concluded its inquiry into the deadly fire aboard the boxship Maersk Honam in 2018. While the bureau was not able to conclusively determine the cause of the inferno, its forensic investigators ruled out electrical faults, fuel tank heating, misdeclared goods and non-IMDG cargo ignition sources, leaving one possibility: a giant block stow of an oxidizing compound called sodium dichloroisocyanurate dihydrate (SDID).
SDID is a chlorinating agent classified as an IMDG Class 9 miscellaneous dangerous good, not a more dangerous Class 5.1 oxidizer. However, like a Class 5.1 chemical, it is highly oxidizing and has the potential for self-decomposition when stowed in bulk, much like the notorious self-heating compound calcium hypochlorite, which is used for identical end purposes.
When Maersk Honam set sail, a total of 1,000 tonnes of SDID was stowed in a cube-shaped stack of 54 containers in her number-three cargo hold, the location where the fire broke out. The stow was fully compliant, and Maersk’s cargo-loading program detected no issues with the arrangement when it was placed on board.
At 1945 hours on March 6, 2018, while she was under way off the coast of Oman, a smoke alarm went off in her number three hold.
The master headed for the bridge, and on the way up, he smelled chlorine, though he saw no smoke. At 1951 hours, he instructed the chief mate to sound the fire alarm, and the crew mustered for a response.
The two designated firefighting teams managed to shut off most of the vents around the hatch for the number three hold, but they could not seal off 16 natural ventilation flaps on the port side. Even though the vents were not fully closed, the master ordered the use of the CO2 flooding system in an attempt to extinguish the blaze.
At 2035 hours, with the smoke worsening, the master ordered all crew to muster on the bridge. He ordered two more rounds of CO2 flooding, including a full discharge on the final round. The last discharge was followed by several explosions and a large plume of smoke, which engulfed the accommodations block and led most of the crew to flee the bridge in panic.
The crew became separated into four groups, and each separately made its way aft to abandon ship. The 23 survivors were rescued by the boxship ALS Ceres, one of them, the ship’s painter, died of his injuries before reaching shore.
During rescue and salvage operations, the bodies of two deceased crewmembers were found on the port side bridge wing, where they had been using fire hoses to assist with boundary cooling during the crew’s firefighting effort. One more was found below the port side lifeboat. The final missing crewmember was not found.
As for Maersk Honam, a multi-week salvage operation finally ended in late April 2018 when she was towed into Jebel Ali. After an extensive process of unloading the surviving cargo and evaluating the extensive damage in her forward holds, Maersk opted to scrap the ship’s bow and deckhouse and ship the stern section to a South Korean yard for repair. The newly-remade vessel is currently trading as Maersk Halifax.
The survivors told investigators that throughout the firefighting and abandon-ship evolutions, they encountered ‘white colored smoke with strong bleach/chemical smell,’ and they experienced breathing difficulty and skin irritation.
A blue Maersk uniform recovered from the ship was bleached nearly white, and firefighting gear showed extensive bleaching discoloration.