A LPG Carrier was on a ballast voyage 120 nautical miles off coast of India when it was reported to the Master that six officers/crew members, including the Chief Officer and the Gas Engineer, had been overcome in the compressor room while working there. On learning about the incident, vessel operator immediately alerted the Navy and Indian Coast Guard for relief and rescue operations. Additionally the vessel was diverted towards the closest port.
Navy and Coast Guard deployed vessels and a helicopter with a medical team for evacuation of the officers/crew members. A team of naval doctors examined the casualties and confirmed that only the Gas Engineer could be saved. The remaining five were declared dead. The helicopter airlifted the survivor to medical facility.
The preliminary investigation carried out by the vessel operator indicates that the team of officers and crew disassembled a spectacle blank (which prevents flow through the pipe) on a pipeline carrying inert gas that was under pressure while the vessel was undergoing a standard ‘gas freeing’ operation. The removal of the spectacle blank, without shutting off the inert gas supply and failure to ensure that there was no inert gas in the pipe, caused a significant release of inert gas into the compressor room, displacing the oxygenated air, causing asphyxiation of the team.
The greatest danger from inert gas is the low oxygen content. Normal air has oxygen content of 21% by volume. As the oxygen content in an atmosphere is lowered, breathing initially becomes both deeper and faster. The susceptibility of individual to this effect is varied, however once the level of oxygen falls to 16% all persons are affected to a greater or lesser degree. These symptoms are usually insufficient to alert the individual to the lack of oxygen. Most would fail to recognize the danger until too weak to escape without aid, especially when climbing or exertion is required. If the atmosphere has less than 10% oxygen content by volume, unconsciousness will inevitably follow. This will become more rapid as the oxygen level lowers, and a victim will soon die unless quickly removed to a pure fresh air atmosphere and resuscitated. At 5% oxygen unconsciousness will result with the first, and possibly a victim’s last, gasp for air. There is no warning of the danger at this level of oxygen deficiency and death will follow swiftly if resuscitation is delayed for little more than a few minutes. Even if revived, a victim can suffer irreversible brain damage.
Note: This incident is a sobering reminder that there is no room for complacency. There is a great deal of emphasis placed on the handling of “dangerous” liquids and gases and strict procedures in place and followed. When handling, seemingly, less dangerous gases such as inert gas or nitrogen, the asphyxiation hazard is perhaps forgotten and the results of inhaling these gases or the displacement of oxygen is over looked. These gases can be equally as deadly as others that are treated with more respect. In this instance the operator and the vessel had received numerous awards for excellent operations and safely, which are testimony to the company’s commitment to safety and quality standards and best practices in management. However, without due diligence and strict adherence to procedures and best practice at all times, accidents can happen and tragedies such as this occur.
