Oxygen depleting cargoes

A recent report from The Nautical Institute International Marine Accident Reporting Scheme (MARS) described an incident in which four stevedores died.

After entering a hold, one of them slipped on a cargo of logs which had been stripped of their bark. When the other stevedores went in to try and rescue him, they too were trapped in the deep spaces between the logs. All four were later brought out unconscious and were pronounced dead on arrival at the hospital. The inherent nature of the cargo, which lead to oxygen depletion in the enclosed space, combined with the slippery surfaces of the logs, created the hazard which led to this tragic incident.

Logs are just one of several cargoes which are known to have oxygen depleting properties. This oxygen depletion can be caused by factors such as self-heating of the cargo, oxidation of metals and ores or decomposition of vegetable oils, animal fats, grain and other organic materials or their residues. The materials listed below are known to be capable of causing oxygen depletion:

• Grain, grain products and residues from grain processing (such as bran, crushed grain, crushed malt or meal), hops, malt husks and spent malt;
• Oilseeds as well as products and residues from oilseeds (such as seed expellers, seed cake, oil cake and meal);
• Copra;
• Wood in such forms as packaged timber, round wood logs, pulpwood, props (pit props and other prop wood), woodchips, wood shavings, wood pulp pellets and sawdust;
• Jute, hemp, flax, sisal, kapok, cotton and other vegetable fibres, empty bags, cotton waste, animal fibres, animal and vegetable fabric, wool waste and rags;
• Fishmeal and fishscrap;
• Guano;
• Sulphidic ores and ore concentrates;
• Charcoal, coal and coal products;
• Direct reduced iron (DRI);
• Dry ice;
• Metal wastes and chips, iron swarf, steel and other turnings, borings, drillings, shavings, filings and cuttings; and
• Scrap metal.