Oxygen Depleting Cargo

A prominent risk while carrying certain cargoes is oxygen depletion due to the inherent form of the cargo, for example, self-heating, 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. However, the list is not exhaustive. Oxygen depletion may also be caused by other materials of vegetable or animal origin, by flammable or spontaneously combustible materials and by materials with high metal content:

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 (such as esparto grass/spanish grass, hay, straw, bhusa), 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

The atmosphere in any enclosed space may be deficient in oxygen and/or contain flammable and/or toxic gases or vapour s. Such an unsafe atmosphere could also subsequently occur in a space previously found to be safe. Unsafe atmosphere may also be present in spaces adjacent to those spaces where a hazard is known to be present.

If fumigation is carried out, detailed recommendations contained in the " Recommendations on the Safe Use of Pesticides in Ships" should be followed. Spaces adjacent to fumigated spaces should be treated as if fumigated.

Conclusion

Failure to observe simple procedures can lead to people being unexpectedly overcome when entering enclosed spaces. While ship's staff are quite aware of such dangers and observe sufficient precautions, it is also obligatory on the part of the vessel to ensure that cargo holds are well ventilated and the stevedoring company warned of inherent dangers with the cargo carried on board before commencement of cargo work.