Insufficient Oxygen Causes Collapse Of Contractors In Cargo Hold

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  • BMA has published a marine investigation report about an incident following the arrival of a team of fumigation contractors onboard the Bahamian registered bulk carrier.
  • A fumigation contractor died and another was seriously injured when they entered a cargo hold that did not have sufficient oxygen to support life.
  • The Bahamas Maritime Authority has continued to work with member States through the auspices of IMO sub-committee on Carriage of Cargoes and Containers (CCC) to revise on Resolution A.1050(27) to improve the recommended practices for entering enclosed spaces aboard ships.

The Bahamas Maritime Authority (BMA) has published a marine investigation report about an incident following the arrival of a team of fumigation contractors onboard the Bahamian registered bulk carrier Magic Striker, reports IIMS.

What happened

On the morning of 21 December 2021, the Bahamian registered bulk carrier Magic Striker had nearly completed loading a cargo of corn in Chennai, India, when a team of fumigation contractors arrived onboard. In the early afternoon, two contractors entered the cargo hold, wearing gas masks along with a phosphine gas detector. Shortly afterwards, one of them climbed back out, feeling breathless. He then noticed his colleague had fallen and went back down the ladder to help him. He too collapsed. After the alarm was raised, the chief officer ran to the hatch and saw the two workers motionless at the bottom of the ladder. He then fetched an emergency escape breathing device which he wore to enter the hold and retrieve both contractors. One of the workers recovered but his colleague did not survive.

Why it happened

Oxygen levels in the cargo hold had been depleted by the corn cargo inside – in the six days that the hatches had been shut, oxygen levels had fallen well below that needed to support life. Dangerous levels of phosphine were also found but toxicology showed no gaseous poison in the blood or lungs of the victim or survivor. The fumigation workers entered cargo hold 4 without the knowledge of the crew and without effective protection – the cargo holds were not considered dangerous spaces and therefore there was no safe system of entry or access control in place. The attempt to help a colleague in distress cost the victim his life. The uncoordinated rescue attempt by the chief officer using unsuitable equipment could have resulted in more victims.

Learnings

Organic cargoes, such as corn, can deplete oxygen (and raise carbon dioxide) to dangerous levels in enclosed spaces rapidly. The fumigation contractors’ protective equipment – gas masks and phosphine detector – offered no protection from the other hazard that they were exposed to. The risk of oxygen depletion was not considered by those onboard or ashore. The human drive to help those in distress is incredibly strong but can prove fatal. The importance of realistic drills to prepare for these scenarios and imprint an appropriate response cannot be underestimated. Shoreside personnel that are subject to the same risks would benefit from similar training.

Atmosphere

Measurements of the atmosphere in the holds were taken by the Indian Mercantile Marine Department four days after the casualty. Oxygen makes up 20.9% of air and there is a threat to human life if levels fall below 19.5%. Breathing air that contains less than 6% oxygen produces convulsions, then apnea (cessation of breathing), followed by cardiac standstill. These symptoms occur immediately. Even if a person survives exposure, their organs may be irreversibly damaged. Phosphine is a poisonous gas commonly used as a pesticide in agriculture. The effects of exposure are usually rapid and there is no antidote – treatment is to provide oxygen. The Bahamas does not have any regulations identifying occupational exposure limits for phosphine but exposure to levels above 1 part per million (ppm) is considered dangerous – even for a short time. Toxicology analysis did not identify any poisoning associated with fumigants in the blood or organs of the victim or survivor. The gas masks they were wearing may have protected them from the exposure to phosphine – unconsciousness and further deterioration of their condition was due to lack of oxygen.

Oxygen depleting cargoes

Recent work presented to the International Maritime Organization has highlighted how quickly the oxygen level can deplete to a dangerous level in holds that contain organic cargoes such as barley, wheat and timber. Experiments were not conducted on corn but other organic cargoes were found to reduce oxygen and increase carbon dioxide from the moment hatches were sealed, with some cargoes reducing oxygen below 19.5% (or raising carbon dioxide to dangerous levels) in under an hour. Higher temperatures and moisture content increased the speed of development of fatal atmospheric conditions. The findings of the study are mirrored in the atmosphere readings taken in the cargo holds of Magic Striker post-casualty – the holds that had been shut longest had the lowest levels of oxygen.

Conclusions

A fumigation contractor died and another was seriously injured when they entered a cargo hold that did not have sufficient oxygen to support life.

  • Oxygen levels in the cargo hold had been depleted by the corn cargo inside – in the six days that the hatches had been shut, oxygen levels had fallen below that needed to support life.
  • The cargos holds were not treat as dangerous spaces and therefore there was no control of access or any safe system of entry in place.
  • Contrary to the cargo documentation and specification, the corn had been fumigated prior to loading – significantly increasing risk to the health of all onboard for the duration of cargo operations.
  • The fumigation contractors protective equipment – gas masks and phosphine detector – offered protection from the phosphine but not to the other hazard that they were exposed to. The risk of oxygen depletion was not considered.
  • The victim re-entered and the cargo hold to help his colleague and was overcome. He was followed by two further colleagues who managed to exit before becoming casualties themselves.
  • The chief officer entered the hold to rescue the victims using unsuitable protection for himself and with insufficient support. The rescue operation was fortunate not to have resulted in further fatalities.

Action taken and Recommendations

As a result of the casualty, Enterprises Shipping & Trading S.A has:

  • Circulated a QHSE alert to its fleet, sharing lessons learned from the casualty including the importance of keeping all entrances to unattended dangerous areas secured against entry. The alert restated that no rescue attempts should be made without wearing breathing apparatus and safety harness and reinforced that the crew has the authority to stop any unsafe activity or behaviour by visitors or contractors that could potentially lead to an incident.
  • Revised procedures for fumigation, emphasizing charterer’s and fumigation team’s responsibilities.

The Bahamas Maritime Authority has continued to work with member States through the auspices of IMO sub-committee on Carriage of Cargoes and Containers (CCC) to revise on Resolution A.1050(27) to improve the recommended practices for entering enclosed spaces aboard ships.

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Source: IIMS

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