TSIB Investigation: Fatality due to cargo hold’s low oxygen concentrations

TSIB Investigation: Fatality due to cargo hold’s low oxygen concentrations
The Editorial Team December 19, 2022 https://safety4sea.com/tsib-investigation-fatality-due-to-cargo-holds-lo...

The Transport Safety Investigation Bureau of Singapore (TSIB) published its accident report on the bulker Nozomi, onboard which a seafarer died after entering a cargo hold, and suffered from oxygen deficient atmosphere.

The incident

On 19 March 2022, Nozomi arrived and anchored at the Tanjung Api-Api (TAA) anchorage, South Sumatera, Indonesia, for loading coal cargo, which took place between 22 and 26 March 2022.

On 1 April 2022, Nozomi waited at the anchorage for cargo export documents, and the departing pilot to embark at about 1200H. At about 1000H, the Bosun asked three ASD’s (ASD1, ASD2 and ASD3) to assist him in carrying out maintenance work (greasing) of the shipboard cargo cranes on the main deck. When the group arrived at No. 4 crane at about 1010H, the Bosun was doubtful whether the grease available on board was appropriate for the moving parts of the cranes. The Bosun informed the Chief Officer (CO) via walkie-talkie of the matter and requested the CO to go to the main deck for confirmation.

The CO, who was resting in his cabin, went to the main deck and met up with the group. After discussing with the Bosun, the CO mentioned that he would inform the Company to supply the correct grease for the cranes at the next available port. The Bosun told the CO that the grease was however suitable for lubricating the dog handles of the booby hatch accessing cargo holds, and that the crew could grease these dog handles instead. Each booby hatch cover is secured by four sets of internal and external dog handles. Each set of the dog handles has a claw to secure the booby hatch cover internally. The CO agreed with the Bosun’s suggestion and thereafter the CO went back to the ship’s accommodation to rest.

The Bosun and the three ASDs transferred the grease and tools to the forward booby hatch. While turning the external dog handles to open the booby hatch cover, two out of the four were found to be seized. The deck crew used a short pipe to slot into the external dog handles and managed to turn them, and thereafter were able to lift open the booby hatch cover.

To free up the seized dog handles for greasing, the Bosun continued using the short pipe, assisted by the ASD2. At the same time, with the booby hatch cover in open position, the ASD1 used a hammer to strike the internal dog handle of the other set of seized-up dog handles. After a few strikes, the external dog handle dropped onto the main deck and was picked up by the ASD3.

At about 1030H, the ASD2 heard a sound from No. 5 cargo hold, he looked over the booby hatch and saw the ASD1 lying on the coal cargo. An internal dog handle7 was found wedged between the vertical ladder and the side stringer of ship’s structure. No one was aware that the ASD1 had entered the cargo hold. The deck crew assessed that the ASD1 could have dropped the internal dog handle into the cargo hold while hammering it and tried to retrieve it without informing anyone.

The Bosun shouted to the ASD1 but did not receive any response. The Bosun ran towards the accommodation to get safety harness and ropes while shouting to attract the attention of other crew members. The ASD2, at about the same time, reported the incident on the walkie-talkie to the Third Officer (3O), who was the duty officer keeping anchor watch on the bridge.

A short while later after the 3O left the bridge, the Master instructed the 2O to remain on the bridge and thereafter the Master went to the incident site. The Master noticed that the ASD1 was motionless lying on the coal cargo and recalled seeing some crew arriving at the site with the EEBD, stretcher, safety harness and some other equipment.

Analysis

The ASD1 was found motionless on the coal cargo and there were no bodily injuries as observed by the crew. The exact cause of death of the ASD1 could not be determined as the body did not undergo an autopsy examination.

Based on available evidence, the ASD1 was medically fit without limitations or restrictions for servicing at sea and had 16 hours of rest in the past 24-hours. He had not performed any strenuous activity since the morning and was last known to be working in freeing up the internal dog handle of the booby hatch’s securing mechanism.

The investigation team considered the possibility of the ASD1 accidentally falling into the cargo hold. Correlating the build (height) of the ASD1, the position where the ASD1 before being discovered and the coaming height (0.8m) of the booby hatch, it is probably unlikely that the ASD1 accidentally fell into the cargo hold. An accidental fall would have caught the attention of the other crew members as well as resulted in some injuries sustained by the ASD1, which was not the case.

The investigation team considered the probability that the internal dog handle had dropped into the cargo hold when the ASD1 was attempting to free it. The ASD1 then entered the cargo hold to retrieve it without informing the other crew. When the ASD1 had retrieved the internal dog handle and was climbing up the ladder, due to the depleted oxygen condition in the cargo hold, he lost consciousness and fell, leaving the dog handle wedged between the ladder and the stringer.

This hypothesis is further corroborated by the height of the ASD1 and the location where the dog handle was found. From the location where the dog handle was found to the coal level, it is about 2.1m. When a person climbs up a vertical ladder, both hands are extended to hold the sides of the ladder. With the height of 1.70m and the arms’ length of about 0.5m, it is likely that the ASD1 was either about to climb up the ladder or making the first couple of steps on the ladder, before losing consciousness. The fall was from a low height which explains the reason for no visible injuries sustained by the ASD1. The investigation team opined that the ASD1 might have deemed the cargo hold to be safe for entry and that retrieving the dog handle was a simple task which could be done quickly.

Probable cause

The ASD1 had likely entered the No.5 cargo hold without the knowledge of the other crew members to retrieve a dog handle. The t due to the cargo of coal. The ASD1 collapsed while climbing out of the cargo hold.

The maintenance of the booby hatch was an unplanned task and did not require entering of cargo hold. The dropping of parts into the cargo hold was not anticipated for this maintenance. The risks associated with working in the vicinity of a hazardous environment (cargo hold loaded with coal) had not been identified, a risk assessment was not carried out.

Furthermore, he hazards associated with the coal cargo had been overlooked when the maintenance of booby hatch was being carried out. There was also a misconception on board the ship that EEBD could be used for rescue operation and the crew used inappropriate equipment to rescue the ASD1. The crew also did not follow the assigned duties as per the muster list.

Finally, here were no signages to warn the crew to treat cargo hold as enclosed space when it has been sealed for some time.