What Are The Nine Classes of Dangerous Goods?

Compliance Knowledge Base | Customs Controls Training

Posted by: Rosie Anderson Published: Fri, 19 Jul 2019 Last Reviewed: Thu, 02 Jul 2020
What Are The Nine Classes of Dangerous Goods?

Dangerous goods are materials or items with physical and chemical properties which, if not properly controlled, present a potential hazard to human health and safety and/or infrastructure. Dangerous goods are separated into categories through a classification system is outlined by the UN Model Regulations. Each dangerous substance or article is assigned to a class.

There are 9 classes of dangerous goods and the class is determined by the nature of the danger they present:

  • Class 1: Explosives
  • Class 2: Gases
  • Class 3: Flammable liquids
  • Class 4: Flammable solids
  • Class 5:Oxidising agents & organic peroxides
  • Class 6: Toxins and infectious substances
  • Class 7: Radioactive material
  • Class 8: Corrosives
  • Class 9: Miscellaneous dangerous goods

Class 1: Explosives

Class 1 goods are explosives - products that possess the ability to alight or detonate during a chemical reaction. Explosives are dangerous because they have molecules designed to rapidly change their state, which is usually a solid state into a very hot gas. There are 6 sub-divisions of explosives, which relate to the product's behaviour when initiated.

  • 1.1: Substances and articles which have a mass explosion hazard
  • 1.2: Substances and articles which have a projection hazard but not a mass explosion hazard
  • 1.3: Substances and articles which have a fire hazard and either a minor blast hazard or a minor projection hazard or both
  • 1.4: Substances and articles which present no significant hazard; only a small hazard in the event of ignition during transport with any effects largely confined to the package
  • 1.5: Very insensitive substances which have a mass explosion hazard
  • 1.6: Extremely insensitive articles which do not have a mass explosion hazard

Examples of explosives include fireworks, flares, and ignitors.

Class 2: Gases

Class 2 consists of compressed gases, gases in their liquefied form, refrigerated gases, mixtures of gases with other vapours and products charged with gases or aerosols. These sorts of gases are often flammable and can be toxic or corrosive. They're also hazardous because they can chemically react with oxygen. They are split into three sub-divisions:

  • Division 2.1: Flammable gases
  • Division 2.2: Non-flammable, non-toxic gases
  • Division 2.3: Toxic gases

Examples of gases include aerosols and fire extinguishers.

Class 3: Flammable liquids

A flammable liquid is defined as a liquid, a mixture of liquids, or liquids containing solids that require a much lower temperature than others to ignite. These temperatures are so low that there is a high risk of the liquids igniting during transportation. This makes flammable liquids very dangerous to handle and transport, as they are very volatile and combustible. Flammable liquids are usually used as fuels in internal combustion engines for motor vehicles and aircraft. This means they make up the largest tonnage of dangerous goods moved by surface transport. Many household products also contain flammable liquids, including perfumery products and acetone (which is used in nail polish remover).

Class 4: Flammable solids

Class 4 dangerous goods are classified as products that are easily combustible and likely to contribute to fires during transportation. Some goods are self-reactive and some are liable to spontaneously heating up. There are 3 sub-divisions for Class 4 dangerous goods:

  • Class 4.1 Flammable solids: These will burn easily than normal combustible materials. The burning of flammable solids is also fierce and rapid; they are also incredibly dangerous because they can decompose explosively, burn vigorously, or produce toxic gases.
  • Class 4.2 Spontaneously combustible: These can be either solids or liquids. They ignite spontaneously when in contact with oxygen.
  • Class 4.3 Dangerous when wet: These goods react with water to generate flammable gas that can be ignited by the heat of the reaction.

Examples of flammable solids include metal powders, sodium batteries and seed cake (oil-bearing seeds).

Class 5: Oxidising Agents and Organic peroxides

Class 5 dangerous goods are subdivided into 'oxidising agents' and 'organic peroxides'. These are often extremely reactive because of their high oxygen content. They react readily with other flammable or combustible materials, which means fires may break out and continue in confined spaces. These materials are also incredibly difficult to extinguish, which makes them even more dangerous.

  • Class 5.1 Oxidising Agents: Also known as oxidisers, these substances that can cause or contribute to combustion as a product of chemical reactions. Oxidisers aren't necessarily combustible on their own, but the oxygen they produce can cause combustion with other materials.
  • Class 5.2 Organic peroxides: The molecular structure of these materials makes them extremely liable to ignition. This means they're liable to combust individually. They are designed to be reactive for industrial purposes, so they are unstable and can be explosive.

Examples include hydrogen peroxide and lead nitrate.

Class 6: Toxins and Infectious substances

  • Class 6.1 Toxins: Toxic substances are liable to cause death because they're, as the name suggests, toxic. They can cause serious injury or harm to human health if they enter the body through swallowing, breathing in, or absorption through the skin. Some toxics will kill in minutes, however, some might only injure if the dose isn't excessive.
  • Class 6.2 Infectious substances: These are goods that contain micro-organisms that cause infectious diseases in humans or animals, otherwise known as pathogens.

Examples include medical waste, clinical waste, and acids.

Class 7: Radioactive material

Radioactive materials contain unstable atoms that change their structure spontaneously in a random fashion. They contain 'radionuclides', which are atoms with an unstable nucleus. It's this unstable nucleus that releases radioactive energy. When an atom changes, they emit ionising radiation, which could cause chemical or biological change. This type of radiation can be dangerous to the human body. Examples include smoke detectors and yellowcake.

Class 8: Corrosives

Corrosives are highly reactive materials that produce positive chemical effects.. Due to their reactivity, corrosive substances cause chemical reactions that degrade other materials when they encounter each other. If these encountered materials happen to be living tissue, they can cause severe injury. Examples include batteries, chlorides and flux.

Class 9: Miscellaneous dangerous goods

This category covers substances that present a danger not covered in the other classes. Examples include dry ice, GMO's, motor engines, seat belt pretensioner, marine pollutants, asbestos, airbag modules and magnetised material.

What Are The Nine Classes of Dangerous Goods?

Hazardous goods vs prohibited goods

Dangerous goods are classified based on their immediate physical or chemical effects, including fires or explosions. Hazardous substances differ because they're classified based only on health effects. Dangerous goods and hazardous substances are covered by separate legislation, however, there is some overlap. The regulations for hazardous substances focus on controlling the different risks associated with them.

Prohibited goods are goods that will be seized at customs. You cannot import or export prohibited goods because they've been banned for reasons linked to health, environment, security and legislation. Examples include illegal drugs, rough diamonds and offensive weapons. In contrast, you can ship dangerous goods, but you need to adhere to the UN Model Dangerous Goods Regulations and obtain a licence.

How do you know if the goods you're shipping are dangerous?

The transportation of dangerous goods is regulated internationally by European agreements, directives and regulations. If you're involved in any part of the carriage of dangerous goods process (this includes processing and packing), you will need to classify them according to the UN classification system.

You can find out whether your shipments are dangerous goods by referring to the UN Dangerous Goods List, or by checking to see if they have a Material Data Safety Sheet. You can also refer to transport-specific regulations set out by bodies such as the International Air Transport Association (IATA), and the ADR (concerning European road transport), International Carriage of Dangerous Goods by Rail, and the International Maritime Organisation (IMO). They can all advise on how to handle and transport your dangerous goods.

The UN Model Dangerous Goods Regulations can also advise on how to pack dangerous goods. When packing shipments, you should consider the packing group, writing the shipment name in upper case letters, hazard class labels UN identification number, UN certification mark, and an orientation label (for liquids). Packages must contain either a Dangerous Goods Note or a Declaration for Dangerous Goods, be able to withstand open weather exposure and all labels must be displayed on contrasting colour background. A Dangerous Goods Note is usually completed by a consignor with qualified personnel within the company. These notes give the receiving authority accurate information about the goods so that they can be handled safely and legally.

Dangerous Goods Note and Declaration for Dangerous Goods

The shipper is responsible for the safe transportation of dangerous goods to their destination. All goods should be correctly declared, packed and labelled with the correct documentation for the countries of origin, transit and destination. Dangerous goods shipments must have either a Dangerous Goods Note (DGN) or a Declaration for Dangerous Goods (for air transport) completed. This will include information about the nature, quantity of goods and other handling information.

What does the Dangerous Goods Note do?

The Dangerous Goods Note (DGN) is a transport document that gives details about the contents of a consignment to carriers, receiving authorities and forwarders. It's an essential part of shipping dangerous goods because it explains how they should be handled and packaged safely. The same standard document can be completed for all consignments of dangerous goods, even if they're going to different ports or Inland Container Depots (ICD). A Dangerous Goods Note is used when you transport goods using any form of transport except air freight. For air freight transport, the IATA Declaration of Dangerous Goods is used instead.

It's very important to use a Dangerous Goods Note, as the receiving authority need complete and accurate information about the dangerous goods in order to handle them safely and legally. Using a DGN means that everyone who encounters your goods has enough information at each movement stage. It's a criminal offence to ignore legislation, but more importantly, improper control over dangerous goods can cause significant and devastating damage to human health and infrastructure.

What legislation is there around dangerous goods?

The Petroleum Act 1879 was the first legislation to address the need for control over dangerous goods. The Health and Safety at Work Act 1974 initiated proposals for a set of regulations that addressed issues such as the classification and packaging and labelling of dangerous substances. Many regulations and legislation have been revoked and replaced over the years, but it's important to understand the most up to date laws.

Other significant legislation includes:

  • ADR Carriage of Dangerous Goods by Road: This applies to all road transport journeys. These regulations are enforced by several different authorities, including the Health and Safety Executive (HSE), the Office for Nuclear Regulation (ONR). The Department for Transport (DfT) also works alongside the police and the Driver and Vehicle Standards Agency (DVSA) to manage these rules.
  • RID Carriage of Dangerous Goods by Rail: This applies to all rail transport journeys. The Office of Rail Regulation (ORR), the HSE, the ONR and the DfT take responsibility for enforcing regulations involving rail transport.
  • IMDG Carriage of Dangerous Goods by Sea: This includes domestic and international journeys. Nationally, the Maritime Coastguard Agency (MCA) is responsible for any matters related to compliance for goods moving by sea.
  • IATA Carriage of Dangerous Goods by Air: This includes all shipments by air, domestic and international. The compliance for goods offered to airlines for carriage by air is monitored by the Civil Aviation Authority (CAA).
  • Tunnel Regulations: For Road and Rail. These are now included in the ADR and RID.

Import and Export Licences

Customs Clearance Procedure is upheld by the customs duty office. This system is designed to prevent illegal and prohibited items entering the country, as well as to determine the number of duties to be paid when importing foods that are subjected to taxation under the local law. Due to these regulations, you need an import or export licence when transporting dangerous goods. The potential use of the item and where you're exporting it to/importing it from determining the licence requirements. There are different licences depending on the nature of the dangerous goods.

It can be difficult to determine whether the goods you're exporting require a licence. You can check online through the UK Strategic Export Control Lists, which lists all the items that require a licence. You can submit a licence application electronically via the online system SPIRE. When you make your application, you'll need the technical specifications and End User Undertakings of your goods.

Types of Licences

There are a variety of different types of licences that you may be able to use to export your goods. For example:

  • Open General Export Licences (OGELs): These licences are available for less restricted exports to less restricted destinations. OGELs are pre-published licences with set terms and conditions which you must adhere to. There are currently over 40 OGELs available which cover a wide range of circumstances. For example, some are for military goods and others are for dual-use goods. If you regularly export restricted items, being an OGEL holder is incredibly advantageous, as it can potentially benefit your business by saving you time and money.
  • Standard Individual Export Licences (SIELs): If your goods, technology, software, destination or situation is not covered by an OGEL, you will need to apply for a Standard Individual Export Licence (SIEL).
  • Open Individual Export Licences (OIELs): This type of licence is designed to cover long-term contracts, projects and repeat business.

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