IMSBC Code defines MHB ( Materials hazardous only in bulk ) as materials which may possess chemical hazards when carried in bulk other than materials classified as dangerous goods in the IMDG Code.

 Below are MHBs listed in IMSBC Code with description and their hazardous nature.

BROWN COAL BRIQUETTES

Brown Coal (Lignite) Briquettes are manufactured by pressing dried brown coal particles into compressed blocks.

Briquettes are easily ignited, liable to spontaneous combustion and will deplete oxygen in cargo space.
 CHARCOAL

Wood burnt at a high temperature with as little exposure to air as possible. Very dusty, light cargo. Can absorb moisture to about 18 to 70% of its weight. Black powder or granules.

May ignite spontaneously. Contact with water may cause self-heating. Liable to cause oxygen depletion in the cargo space. Hot charcoal screenings in excess of 55oC should not be loaded.

COAL

Coal (bituminous and anthracite) is a natural, solid, combustible material consisting of amorphous carbon and hydrocarbons.

Coal may create flammable atmospheres, may heat spontaneously, may deplete the oxygen concentration, may corrode metal structures. Can liquefy if predominantly fine 75% less than 5 mm coal.

DIRECT REDUCED IRON (A)

A metallic grey colloid material emanating from a densification process whereby the direct reduced iron (DRI) feed material is at a temperature greater than 650oC at time of moulding and has a density greater than 5.0 g/cm3. Fines (under 4 mm) not to exceed 5%.

Material may slowly evolve hydrogen after contact with water. Temporary self-heating of about 30oC may be expected after material handling in bulk.

This cargo is non-combustible or has a low fire-risk.

DIRECT REDUCED IRON (B)

Direct Reduced Iron (DRI) (B) is a metallic material of a manufacturing process formed by the reduction (removal of oxygen) of iron oxide at temperatures below the fusion point of iron.

Cold-moulded briquettes should be defined as those which have been moulded at a temperature of under 650oC or which have a density of less than 5.0 g/cm3.

DRI may react with water and air to produce hydrogen and heat. The heat produced may cause ignition. Oxygen in an enclosed space may be depleted.

FERROPHOSPHORUS

An alloy of iron and phosphorus used in the steel industry

May evolve flammable and toxic gases (e.g. phosphine) in contact with water.

This cargo is non-combustible or has a low fire-risk.

FERROSILICON

25% to 30% silicon, or 90% or more with silicon (including briquettes)

Ferrosilicon is an extremely heavy cargo.

In contact with moisture or water it may evolve hydrogen, a flammable gas which may form explosive mixtures with air and may, under similar circumstances, produce phosphine and arsine, which are highly toxic gases.

This cargo is non-combustible or has a low fire-risk.

FLUORSPAR

Yellow, green or purple crystals. Coarse dust.

This material may liquefy if shipped at moisture content in excess of their Transportable moisture limit. See section 7 of the Code. Harmful and irritating by dust inhalation.

LIME (UNSLAKED)

White or greyish-white in colour.

Unslaked lime combines with water to form calcium hydroxide (hydrated lime) or magnesium hydroxide. This reaction develops a great deal of heat which may be sufficient to cause ignition of nearby combustible materials. This is not combustible or has a low fire-risk corrosive to eyes and mucous membranes.

This cargo is non-combustible or has a low fire-risk.

LINTED COTTON SEED

Cottonseed with short cotton fibres adhering to the kernel after approximately 90% – 98% of the cotton has been removed by machine.

May self-heat and deplete oxygen in cargo space.

MAGNESIA (UNSLAKED)

Combines with water to form magnesium hydroxide with an expansion in volume and a release of heat. May ignite materials with low ignition temperatures. Similar to LIME (UNSLAKED) but is less reactive. Corrosive to eyes and mucous membranes.

This cargo is non-combustible or has a low fire-risk.

METAL SULPHIDE CONCENTRATES

Mineral concentrates are refined ores in which the valuable components have been enriched by eliminating the bulk of waste materials. Generally the particle size is small although agglomerates sometimes exist in concentrates which have not been freshly produced

.The most common concentrates in this category are: zinc concentrates, lead concentrates, copper concentrates and low grade middling concentrates.

Some sulphide concentrates are liable to oxidation and may have a tendency to self-heat, with associated oxygen depletion and emission of toxic fumes. Some materials may present corrosion problems.

When a Metal Sulphide Concentrate is considered as presenting a low fire-risk, the carriage of such cargo on a ship not fitted with a fixed gas fire extinguishing system should be subject to the Administration’s authorization as provided by SOLAS regulation II-2/10.7.1.4.

PEAT MOSS

Surface mined from mires, bogs, fens, muskeg and swamps. Types include moss peat, sedge peat and grass peat. Physical properties depend on organic matter, water and air content, botanical decomposition and degree of decomposition.

May range from a highly fibrous cohesive mass of plant remains which when squeezed in its natural state exudes clear to slightly coloured water, to a well decomposed, largely amorphous material with little or no separation of liquid from solids when squeezed.

Typically air-dried peat has low density, high compressibility and high water content; in its natural state it can hold 90 percent or more of water by weight of water when saturated.

Oxygen depletion and an increase in carbon dioxide in cargo and adjacent spaces.

Risk of dust explosion when loading. Caution should be exercised when walking or landing heavy machinery on the surface of uncompressed Peat Moss.

Peat Moss having a moisture content of more than 80% by weight should only be carried on specially fitted or constructed ships  Dust may cause eye, nose and respiratory irritation.

PETROLEUM COKE (calcined or uncalcined)

 Black, finely divided residue from petroleum refining in the form of powder and small pieces.

Uncalcined petroleum coke is liable to heat and ignite spontaneously when not loaded and transported under the provisions of this entry.

This cargo is non-combustible or has a low fire-risk.

PITCH PRILL

 Pitch Prill is made from tar produced during the coking of coal. It is black with a distinctive odour. It is extruded into its characteristic pencil shape to make handling easier.

Cargo softens between 40ºC to 50ºC. Melting point: 105ºC to 107ºC

Melts when heated. Combustible, burns with a dense black smoke. Dust may cause skin and eye irritation. Normally this cargo has a low fire-risk. However powder of the cargo is easy to ignite and may cause fire and explosion. Special care should be taken for preventing fire during loading or discharging.

PYRITES, CALCINED (Calcined Pyrites)

 Dust to fines, Calcined Pyrites is the residual product from the chemical industry where all types of metal sulphides are either used for the production of sulphuric acid or are processed to recover the elemental metals – copper, lead, zinc, etc. The acidity of the residue can be considerable, in particular, in the presence of water or moist air, where pH values between 1.3 and 2.1 are frequently noted.

Highly corrosive to steel when wet. Inhalation of dust is irritating and harmful. Cargo may

liquefy. This cargo is non-combustible or has a low fire-risk.

SAWDUST

Fine particles of wood.

Spontaneous combustion if not clean, dry and free from oil. Liable to cause oxygen depletion within the cargo space.

SILICOMANGANESE

 Silicomanganese is an extremely heavy cargo, silvery metallic material with a grey oxide coating.

HAZARD

In contact with water may evolve hydrogen, a flammable gas that may form explosive mixtures with air and may, under similar conditions produce phosphine and arsine, which are highly toxic gases.

Cargo is liable to reduce oxygen content in a cargo space.

This cargo is non-combustible or has a low fire-risk

TANKAGE

The dried sweeping of animal matter from slaughterhouse floors. Very dusty.

Subject to spontaneous heating and possible ignition. Possibly infectious.

VANADIUM ORE

 Dust may be toxic.

This cargo is non-combustible or has a low fire-risk

WOODCHIPS

Natural timber mechanically chipped into the approximate size of a business card.

This material possesses a chemical hazard. Some shipments may be subject to oxidation leading to depletion of oxygen and increase of carbon dioxide in cargo and adjacent spaces.

With moisture content of 15% or more this cargo has a low fire-risk. As the moisture content decreases the fire risk increases. When dry, woodchips can be easily ignited by external sources; are readily combustible and can ignite by friction.

WOOD PELLETS

 The Wood Pellets are light blond to chocolate brown in colour; very hard and cannot be easily squashed. Wood Pellets have a typical specific density between 1,100 to 1,700 kg/m3 and a bulk density of 600 to 750 kg/m3. Wood Pellets are made of sawdust, planer shavings and other wood waste such as bark coming out of the lumber manufacturing processes. Normally there are no additives or binders blended into the pellet, unless specified. The raw material is fragmented dried and extruded into pellet form. The raw material is compressed approximately 3.5 times and the finished Wood Pellets typically have a moisture content of 4 to 8%. Wood Pellets are used as a fuel in district heating and electrical power generation as well as a fuel for small space heaters such as stoves and fireplaces.

Wood Pellets are also used as animal bedding due to the absorption characteristics. Such Wood Pellets typically have a moisture content of 8 to 10%.

Shipments may be subject to oxidation leading to depletion of oxygen and increase of

carbon monoxide and carbon dioxide in cargo and communicating spaces.

Swelling if exposed to moisture. Wood Pellets may ferment over time if moisture content is over 15% leading to generation of asphyxiating and flammable gases which may cause spontaneous combustion.

Handling of Wood Pellets may cause dust to develop. Risk of explosion at high dust concentration.

WOOD PULP PELLETS

 The pellets are brown in colour; very hard and cannot be easily squashed. They are light and are about half the size of a bottle cork. The pellets are made of compacted woodchips.

This cargo possesses a chemical hazard. Some shipments may be subject to oxidation leading to depletion of oxygen and increase of carbon dioxide in cargo and adjacent spaces. With moisture content of 15% or more this cargo has a low fire-risk. As the moisture content decreases, the fire risk increases.

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