Case study: saturation diver fatality due to hydrogen sulphide

The incident happened on board a vessel operating in an offshore oil field, on a long charter for carrying out inspection, maintenance and repair duties. An oil leak was discovered in one of the main 36-inch (91cm) diameter subsea lines carrying sour crude.

The vessel was directed to proceed to the site and carry out pipeline repairs on an emergency basis at 74 msw depth. A diver was deployed from the bell at 65m depth, a short distance away from the pipeline, not directly above it. On reaching the seabed, the diver approached the leaking pipeline to locate the rupture and conduct a close survey of the leak area and the pipeline. The seabed all around the trench was covered with oil sludge.

After getting preliminary details, he returned to the bell. Shortly after he had returned to the bell, first the bellman, then the diver himself, collapsed. Not having secured the safety harness, the diver fell into the water and was carried away by the current, and drowned.

A bell-to-bell rescue of the bellman was arranged with equipment and divers from another nearby vessel. Following medical treatment, he made a full recovery and was diving a month later. The lost diver’s body was recovered the following day.

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