Dangerous goods are substances or articles with hazardous properties which may, if handled incorrectly, explode, asphyxiate (choke), burn, make explosive mixtures, poison, eat skin or metal, pollute the environment or become unstable if mixed with other products.
For ease of identification of dangerous goods, the international community has created a classification system. All dangerous goods are included in one of nine primary classes. In some cases it has also been necessary to sub-divide some of the classes into divisions in order to adequately provide articulations for the dangers of the individual goods.
The 9 Classes of Dangerous Goods
The transportation of dangerous goods is controlled and governed by a variety of different regulatory regimes, operating at both the national and international levels. Prominent regulatory frameworks for the transportation of dangerous goods include the United Nations Recommendations on the Transport of Dangerous Goods, ICAO’s Technical Instructions, IATA’s Dangerous Goods Regulations and the IMO’s International Maritime Dangerous Goods Code. Collectively, these regulatory regimes mandate the means by which dangerous goods are to be handled, packaged, labelled and transported.
Regulatory frameworks incorporate comprehensive classification systems of hazards to provide a taxonomy of dangerous goods. Classification of dangerous goods is broken down into nine classes according to the type of danger materials or items present ie; Explosives, Gases, Flammable Liquids, Flammable Solids, Oxidizing Substances, Toxic & Infectious Substances, Radioactive Material, Corrosives and Miscellaneous Dangerous Goods.
Class 1 - Explosives
Explosives are materials or items which have the ability to rapidly conflagrate or detonate as a consequence of chemical reaction. Explosives are capable by chemical reaction of producing gases at temperatures, pressures and speeds as to cause catastrophic damage through force and/or of producing otherwise hazardous amounts of heat, light, sound, gas or smoke.
Division 1.1: Substances and articles which have a mass explosion hazard
Division 1.2: Substances and articles which have a projection hazard but not a mass explosion hazard
Division 1.3: Substances and articles which have a fire hazard and either a minor blast hazard or a minor projection hazard or both
Division 1.4: Substances and articles which present no significant hazard; only a small hazard in the event of ignition or initiation during transport with any effects largely confined to the package
Division 1.5: Very insensitive substances which have a mass explosion hazard
Division 1.6: Extremely insensitive articles which do not have a mass explosion hazard
Class 2 - Gasses
Gases are defined by dangerous goods regulations as substances which have a vapour pressure of 300 kPa or greater at 50°c or which are completely gaseous at 20°c at standard atmospheric pressure, and items containing these substances. The class encompasses compressed gases, liquefied gases, dissolved gases, refrigerated liquefied gases, mixtures of one or more gases with one or more vapours of substances of other classes, articles charged with a gas and aerosols.
Gases are capable of posing serious hazards due to their flammability, potential as asphyxiants, ability to oxidize and/or their toxicity or corrosives to humans.
Class 3 - Flammable Liquids
Flammable liquids are defined by dangerous goods regulations as liquids, mixtures of liquids or liquids containing solids in solution or suspension which give off a flammable vapour (have a flash point) at temperatures of not more than 60-65°C, liquids offered for transport at temperatures at or above their flash point or substances transported at elevated temperatures in a liquid state and which give off a flammable vapour at a temperature at or below the maximum transport temperature.
Flammable liquids are capable of posing serious hazards due to their volatility, combustibility and potential in causing or propagating severe conflagrations.
Class 4 - Flammable Solids
Flammable solids are materials which, under conditions encountered in transport, are readily combustible or may cause or contribute to fire through friction, self-reactive substances which are liable to undergo a strongly exothermic reaction or solid desensitized explosives. Also included are substances which are liable to spontaneous heating under normal transport conditions, or to heating up in contact with air, and are consequently liable to catch fire and substances which emit flammable gases or become spontaneously flammable when in contact with water.
Flammable solids are capable of posing serious hazards due to their volatility, combustibility and potential in causing or propagating severe conflagrations.
Sub-Divisions Division 4.1: Flammable solids
Division 4.2: Substances liable to spontaneous combustion
Division 4.3: Substances which, in contact with water, emit flammable gases and are considered dangerous when wet
Class 5 - Oxidizing Substances
Oxidizers are defined by dangerous goods regulations as substances which may cause or contribute to combustion, generally by yielding oxygen as a result of a redox chemical reaction. Organic peroxides are substances which may be considered derivatives of hydrogen peroxide where one or both hydrogen atoms of the chemical structure have been replaced by organic radicals.
Oxidizers, although not necessarily combustible in themselves, can yield oxygen and in so doing cause or contribute to the combustion of other materials. Organic peroxides are thermally unstable and may exude heat whilst undergoing exothermic autocatalytic decomposition. Additionally, organic peroxides may be liable to explosive decomposition, burn rapidly, be sensitive to impact or friction, react dangerously with other substances or cause damage to eyes.
Class 6 - Toxic Substances
Toxic substances are those which are liable either to cause death or serious injury or to harm human health if swallowed, inhaled or by skin contact. Infectious substances are those which are known or can be reasonably expected to contain pathogens. Dangerous goods regulations define pathogens as microorganisms, such as bacteria, viruses, rickettsiae, parasites and fungi, or other agents which can cause disease in humans or animals.
Toxic and infectious substances can pose significant risks to human and animal health upon contact.
Sub-Divisions Division 6.1: Toxic substances
Division 6.2: Infectious substances
Commonly Transported Toxic Substances
Medical & Biomedical waste, Clinical waste, Biological cultures or samples or specimens, Medical cultures or samples or specimens, Tear gas substances, Motor fuel anti-knock mixture, Dyes, Carbamate pesticides, Alkaloids, Allyls, Acids, Arsenates, Arsenites, Cyanides, Thiols & mercaptans, Cresols, Barium compounds, Arsenics & arsenic compounds, Beryllium & beryllium compounds, Lead compounds, Mercury compounds, Nicotine & nicotine compounds, Selenium compounds, Antimony, Ammonium metavanadate, Adiponitrile, Chloroform, Dichloromethane, Hexachlorophene, Phenol, Resorcinol.
Class 7 - Radioactive Materials
Dangerous goods regulations define radioactive material as any material containing radionuclides where both the activity concentration and the total activity exceeds certain pre-defined values. A radionuclide is an atom with an unstable nucleus and which consequently is subject to radioactive decay.
Whilst undergoing radioactive decay radionuclides emit ionizing radiation, which presents potentially severe risks to human health.
Class 9 - Miscellaneous Dangerous Goods
Miscellaneous dangerous goods are substances and articles which during transport present a danger or hazard not covered by other classes. This class encompasses, but is not limited to, environmentally hazardous substances, substances that are transported at elevated temperatures, miscellaneous articles and substances, genetically modified organisms and micro-organisms and (depending on the method of transport) magnetized materials and aviation regulated substances.
Miscellaneous dangerous goods present a wide array of potential hazards to human health and safety, infrastructure and/ or their means of transport.
Commonly Transported Miscellaneous Dangerous Goods
Dry ice / cardice / solid carbon dioxide, Expandable polymeric beads & polystyrene beads, Ammonium nitrate fertilizers, Blue asbestos & crocidolite, Lithium ion batteries, Lithium metal batteries, Battery powered equipment, Battery powered vehicles, Fuel cell engines, Internal combustion engines, Vehicles, Magnetized material, Dangerous goods in apparatus, Dangerous goods in machinery, Genetically modified organisms, Genetically modified micro-organisms, Chemical kits, First aid kits, Life saving appliances, Air bag modules, Seatbelt pretensioners, Plastics moulding compound, Castor bean plant products, Polychlorinated biphenyls, Polychlorinated terphenyls, Dibromodifluoromethane, Benzaldehyde.
Mixed Class Dangerous Goods
This is not part of the UN labeling system and is not included in the modal codes. Valid only for road or rail transport within Australia. Principally used as a placard on transport units transporting more than one class or division of dangerous goods.
Some chemicals pose a danger to aquatic life. The International Maritime Dangerous Goods code part 18.104.22.168 states that all marine pollutants must be labelled for transport by sea, with the exception of packages containing less than or equal to 5L or 5kg. This is a sub-risk label only and is used with the other primary classes of labels.
Transport units and placard units containing a substance that is transported or offered for transport in a liquid state at a temperature equal to or exceeding 100°C, or in a solid state at a temperature equal to or exceeding 240°C. Used in conjunction with Dangerous Goods Class Labels for substances requiring storage or transport at elevated temperatures.
Dangerous goods in limited quantities (designated as in section 3.4 of the IMDG Code) are exempt from certain requirements in the IMDG code due to the consideration that they are packed individually, in small quantities, which gives an acceptable level of safety through quantity limitations. Dangerous goods transported according to these special provisions shall be packaged only in inner packaging placed in suitable outer packaging. The total gross mass of a package shall not exceed 30kg or 20kg if the “outer packaging” is provided by shrink or stretch wrap.