Zinc and zinc products 
May have dangerous and hazardous properties. When dealing with these commodities it is advisable to make reference to the ‘International Maritime Dangerous Goods Code’. Zinc and some manufactures or derivatives thereof are variously affected by water, salt or fresh, depending on the nature of the commodity and its uses; the monetary loss will reflect the cost of the remedial treatment and/or variation of quality, etc., of the ultimate product or by-product.

Zinc (Slab)
– Zinc in massive form is liable to superficial corrosion by immersion in or exposure to salt or fresh water. While the corrosion product can be fairly easily removed by brushing, its presence leads to an increased loss in subsequent melting operations and may therefore represent some loss in value.

Zinc Ashes
– Class 4.3 Dangerous when wet.
Liable to give off dangerous gases in contact with water or very humid atmosphere accompanied by heating. Should be packed in effectively closed tin cans or steel drums.

Zinc Chloride – IMDG Class 8 Corrosive
Solution or solid, corrosive, burns the skin.

Zinc Concentrates – When shipped in bulk may be subject to loss in weight and liquefaction; see also Concentrate (of Minerals). The presence of chlorides reduces the value of the concentrates and contact with sea water results in the deterioration of value due to the increase of chlorine content. The extent of the chlorine content determines the degree of damage. At the time of shipment the concentrates may contain a small percentage of moisture, and if it is proposed to overstow with other cargo, it is recommended that the ore be double dunnaged and double ‘sisal’ paper be used to prevent the rising of moisture damaging cargo stowed on top.

Zinc Dust – IMDG Class 4.2 Spontaneously combustible, also dangerous when wet – A hazardous cargo which should be shipped in hermetically sealed lined cases or metal drums. Evolves hydrogen when in contact with water, humid atmosphere, etc., and may ignite. Exposure to moisture should be avoided. Would require complete reprocessing if wet.

Zinc Phosphide – IMDG Class 4.3 Dangerous when wet – Insoluble in water and in the absence of air will decompose only at a very high temperature. It is unlikely, therefore, that this commodity will suffer damage by heat unless this is higher than the melting point of zinc. Reacts violently with oxidizing agents, produces toxic and flammable phosphine by reaction with acids. Toxic by ingestion and a deadly poison.

Zinc Sheets – Access of water between closely packed sheets by condensation or otherwise may damage them through the formation of a white corrosion product known as ‘white rust’. This will reduce coating thickness and spoil the appearance of both galvanized and zinc sheets. These effects are largely due to access of moisture in a limited supply of air and should be avoided by spacing the sheets, or storing or stowing in a dry well-ventilated place. Any sheets that have become wet during transit should be wiped dry before storage. Where outside wrappers are clean and dry, with no signs of water entry, but the sheets themselves show a white deposit, it is possible that the sheets have been packed in a warm and moist atmosphere with subsequent cooling of the sheets causing condensation, giving rise to corrosion.

Note: Consult the IMSBC Code (International Maritime Solid Bulk Cargoes Code) on zinc ashes/concentrates, and IMDG Code (International Dangerous Goods Code) on zinc products for overseas transport.