Hazardous and dangerous goods need to be handled with the appropriate care – self explanatory, really. Transporting these types of goods comes with (potentially) great risk, and if the right procedures are not carried out, it may lead to fatality. From symbols and codes, to how the rules and regulations were introduced, FORWARDER has put together a ‘hazardous and dangerous goods 101.’ Think of it as your very own dangerous goods freight bible, if you like…

Dangerous or Hazardous?

Dangerous goods (abbreviated as DG) are generally items or substances that pose a risk to health, safety, property or the environment when being transported. Hazardous goods or materials (abbreviated as HAZMAT) are substances – solids, liquids or gases – that can harm people, animals, property or the environment, and therefore have to adhere to chemical regulations.

Hazardous goods include materials that are radioactive, flammable, explosive, corrosive, oxidizing, toxic, pathogenic or allergenic. Furthermore, physical conditions such as compressed gases and liquids or hot materials can be classified as hazardous during certain circumstances, for example a gas reaching a temperature that could make it inherently dangerous.

The Globally Harmonized System of Classification & Labelling of Chemicals (GHS)

The GHS is a classification of hazardous and dangerous goods which is internationally known and agreed. The GHS body is managed by the United Nations and uses standardised hazard testing criteria, universal warning pictograms and safety sheets which contain information about types of hazardous products. The regulations for hazardous and dangerous goods to be carried by road are highly prescriptive. 

The GHS label and standardised information took quite a while to become highly prevalent in industry, but the system has been widely used as of 2017 in most major countries around the world, including throughout the EU.  

How did the regulations & dangerous goods legislation start?

The very first regulations created for dangerous goods classification was in a consultative document, published in the late 1970s following the introduction of the Health and Safety at Work Act in 1974. This document was, however, too complex, and was later changed in the following three divisions…

  • The Classification, Labelling and Packaging of Dangerous Substances Regulations 1984 (CPR)
  • The Dangerous Substances (Conveyance by Road in Road Tankers and Tank Containers) Regulations 1981 (RTR)
  • The Dangerous Substances (Conveyance by Road in Packages) Regulations 1986 (PGR)

Fast forward to more recent times and a European agreement regarding the International Carriage of Dangerous Goods by Road (ADR) came into force in 2004. The ADR agreement grants permission for dangerous goods to travel between multiple countries, under the condition that the full requirements are met. 

According to IATA, Sub-Section 1.5 of the IATA Dangerous Goods Regulations (DGR) requires training for dangerous good handlers and transporters. Required levels of training are dependent on the occupational responsibility, but it applies to all industry workers involved in air transport, freight forwarding, ground service providers and airlines.

NOTE: There have been significant changes to the 60th edition of the Dangerous Goods Regulations (DGR), which went into effect 1 January 2019. Please ensure you have read the most up-to-date document if you are involved in hazardous or dangerous goods transportation. 

Importing dangerous goods internationally

In the need for international dangerous goods transport, international standards must be met as governed by the UN Committee of Experts, which are contained in a so-called ‘orange book’, which covers all information from codes, classification, packaging, labelling and the transport modes of dangerous goods.  

How are dangerous goods labelled?

Dangerous and hazardous goods are usually labelled with a diamond-shaped sign with a red border to signify danger (regional versions also exist). The Globally Harmonized System of Classification and Labelling of Chemicals lists the following signs depending on the type and severity of the substance. Label elements include…

Symbols – These are GHS hazard pictograms, which convey information regarding health, physical and environment. Harmful chemicals and irritants are marked with an exclamation mark to warn for its danger. Pictograms are usually diamond-shaped, with red borders, white backgrounds and black symbols. 

Signal words – Words that signify ‘danger’ or ‘warning’ are used to highlight hazards and differentiate the severity between hazard categories. Only one word should be used per label, and the word should only be used for the most severe hazards. 

GHS Hazard statement – Standardised phrases that are allocated to categories which describe the nature of the hazard. For products that contain more than one hazard, clear and correct information displaying these hazards is required.

Product identifier – this is essentially an ingredient disclosure, which names (and numbers) the hazardous product contents which should also incorporate the substance’s chemical identity. Labels should also include a description of how corrosive or harmful it is to the body, such as skin irritation, serious eye damage, germ cell mutagenicity etc..

Supplier identification – the contact details (name, address, telephone number) of the supplier.

Classes of hazardous goods

Hazardous goods are classified into divisions. These classification descriptions are required to be documented when handling and transporting the goods.

Class 1, Explosives

Explosives contain material apt to changing from its resting state into (very hot) gas. This produces a rapid and violent chemical reaction, otherwise known as an explosion. When an explosion occurs, the chemical energy (heat) rises to several thousand degrees, expanding and forcing outwards. There is a range of low and high explosives, and not all chemical reactions are triggered in the same way. Some react from violent shock (e.g. a high-speed traffic accident), high temperatures (e.g. fire), and some even by low temperature.

There are six divisions of explosives in Class 1, ranging from high-explosive reactions to low. These divisions are crucial when transporting loads, as the different types of loads will most likely need different levels of care, safety procedures and transport specifications. 

Explosives are acknowledged as NEQ (Net Explosive Quantity) when documented during transport, which is usually unconnected to the gross weight.


  • Mass explosion hazard
  • Projection hazard only
  • Fire hazard and minor blast or minor projection hazard
  • Minimal hazard
  • Blasting agents
  • Very insensitive denoting articles

Class 2, Gases

Gases tend to be stored under pressure in order to reduce its volume, saving space when transporting and storing. Should the pressure be released suddenly, the fast air release can create high energy release and rocketing, putting the surroundings in danger. Furthermore, as most gases are denser and heavier than oxygen, meaning that exposure of the gases in confined spaces can cause suffocation. Some gases liquefy under pressure in normal temperatures, such as chlorine and ammonia. 

Gases are also separated into divisions due to their physical dangers:

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

Class 3, Flammable liquids

Flammable liquids such as petroleum (petrol) and industrial processed (alcohol) are highly flammable if exposed to a naked flame. Fuels are one of the largest tonnage of dangerous goods transported in the freight industry. The flashpoint for petrol is -40º C, meaning it burns at normal temperatures, whilst diesel’s is 65º C, which has to be heated to be able to burn. The UN Class 3 limit is generally flashpoint 60º C, which is not classified as dangerous for transport. 

Flammable liquids are set in Packing Groups in reference to their boiling point and flashpoint.

Packing Group Initial Boiling Point Flashpoint (closed cup)

  • I Below 35º C
  • II Above 35 º C Below 23 º C
  • III Above 35 º C >23 º C and <60 º C    

Class 4.1/4.2/4.3
Flammable solids
Spontaneously combustible
Dangerous when wet

  • 4.1 – Flammable solids, usually burn more easily than materials like wood and paper. When burning of these flammable solids occur, the flames will be aggressive and rapid, resulting in high levels of heat. Flammable solids can also decompose dangerously and produce toxic gases.
  • 4.2 – Spontaneously combustible, can either be in solid or liquid form. Spontaneously ignite when in contact with oxygen, so must be kept in airtight protection or as liquids under a special blanket. Ignition levels can vary depending on the material, ranging from five minutes to lengthy periods of time. Classification also adheres to Packing Groups I, II and III depending on the ignition level of the material. 
  • 4.3 – Dangerous when wet, reacting with water (liquid or vapour form), which causes flammable gases. These flammable gases can ignite through the heat of the reaction. Class 4.3 must be kept in watertight, sealed containers.

Class 5.1 / 5.2
Oxidising Agents
Organic peroxides

  • 5.1 – Oxidising Agents, feature high oxygen content, which can be the reason for a chemical reaction. May oxidise with other flammable and combustible materials, producing heat and resulting in fire and burning. The only way to put out an Oxidising Agent-caused fire is by large amounts of cold water.
  • 5.2 – Organic peroxides, its molecule structure contains carbon and oxygen which makes the substance vulnerable to ignition. Materials are likely to be used in industrial settings, and can as a result be unpredictably explosive. Usually classified as either Class 1 or Class 5.2, reflective of its purpose. Often kept at a temperature-controlled (refrigeration) level to keep the molecules inactive and to prevent from reacting (and creating a fire or explosion). Organic peroxides can be highly damaging to the human body, specifically the eyes. 

Class 6.1/6.2
Infectious substances

  • 6.1 – Toxics, which are chemical poisons that can cause damage to the human body, whether it be exclusive to one exposed part, or the entire body. Toxics must not be able to get inside of the body, whether it be through swallowing, breathing or absorption of the skin as the toxics can kill in minutes. Some toxics may not kill if the exposure is low, but will harm the body. 6.1 can be in solid or liquid form, and toxic gasses are classified as Class 2.3.
  • 6.2 – Infectious substances, contains pathogens, such as micro-organisms that can cause infectious diseases in both animals and humans if exposed to the substance. 
  • Category A – Substance is capable of causing permanent disability or life-threatening diseases to humans or animals. Examples are: Rabies Virus, Ebola Virus and Hepatitis B Virus.   

Class 7

Radioactives are materials that have unpredictable atoms that change their structure at random over a period of time, emitting radiation that can be harmful to animals and humans. Depending on the type of radiation, exposure can cause damage to the body, including mutation and biological changes. Radioactive packages are generally safe to import and export, as the packaging acts as protection. However, it can still be dependent on how radioactive the source is.

Class 8

Corrosives, often described as acids of alkalis, are highly damaging substances that can cause positive chemical changes, affecting the material that has come in contact with it. This can be highly damaging to the body, destroying tissue and organs in the human body. 

Corrosives are packaged specially with the corrosive level considered. Assigned to Packing Groups, corrosives are packaged according to its ability to destroy the full thickness of skin tissue over an observation period. There are strict requirements for transporting corrosives, especially via ocean freight.

Class 9
Other Substances

Class 9 covers the substances that aren’t already covered by the previous classes, yet still threat some sort of danger. Furthermore, these properties cannot be included in the UN Class system due to crossing two or more Class boundaries. The information has to be recorded on the individual material to warn for dangers and what the contents includes. The two UN numbers in Class 9 for environmentally hazardous materials. UN 3077 Environmentally Hazardous Substance Solid N.O.S and UN 3082 Environmentally Hazardous Substance Liquid N.O.S.  

Packaging and tanks

As highlighted in some of the classified substances above, materials may need special packaging or tanks to contain them. Whether it be for storage or transport purposes (or both), it is vital that the packaging is suitable. Should the goods be incorrectly packaged or stored, it could increase risks, and even trigger ignition, corrosion or harm.

Referring to volume 2 of the aforementioned ‘orange books’, ADR require that the packaging is defined by standardised terms (Chapters). Transporters are also required to list details regarding the construction and testing of the packagings/tanks. 

Here is an example of the details that should be provided when listing the packaging and/or tanks when transporting a load:

  • UN No.1263 Paint product in PG I (first entry) 
  • Column 8 shows that it may be packed according
    to the instruction P001 
  • In turn, top of column 8 directs you to para 4.1.4, which gives the details of what P001 allows.
    A wide range of packaging types is given.

(Taken from hse.gov.uk )

Different requirements may apply according to the details of previously mentioned, Packaging Group (PG). 

In most cases, packaging needs to be certified to UN standards. Testing may need to be carried out on the packaging to test for its durability. Certified packaging is referred to as ‘type-approved’, or ‘UN certified’. 

Examples of types of tanks are pressure receptacles (aerosols), intermediate bulk containers, portable tanks and vacuum-operated waste tanks.

Safety Data Sheet

The Safety Data Sheet (SDS) are key documents that must be used to safely supply, handle and use chemicals. It is required to be used by the REACH (Registration, Evaluation, Authorisation and restriction of Chemicals) Regulation, and is enforced for safety reasons due to the high-risk nature of the dangerous goods. The SDS details about the hazardous goods plus risk assessment information by Control of Substances Hazardous to Health Regulations (COSHH). A SDS is not an assessment itself, but more of an informative document. 

When should you supply an S.D.S? 

According to REACH Regulations, you must provide a SDS if you supply a substance or mixture that is classified as hazardous under the CLP Regulation, if you are a supplier and your customer requests a SDS, or you are a supplier of a product listed as ‘special case’ in the CLP Regulation. Even in the event of using materials that are not classified as hazardous, but contain small amounts of hazardous substances, a SDS is required. Full details for when you should supply a SDS can be found on the REACH document on the hse.gov.uk website.  

What information needs to be listed on an S.D.S? 

  1. Identification
  2. Hazard(s) identification
  3. Composition/ information on ingredients
  4. First-aid measures
  5. Fire-fighting measures
  6. Accidental release measures
  7. Handling and storage
  8. Exposure control/ personal protection
  9. Physical and chemical properties
  10. chemical stability and reactivity
  11. Toxicological information
  12. Ecological information
  13. Disposal considerations
  14. Transport information
  15. Regulatory information
  16. Other information

Transporting hazardous goods

Hazardous goods have to be transported with care. Depending on the mode of transport, special requirements may have to be made in order for the load to reach its destination safely with minimal risks. For example, dangerous Class 1 high-pressure gas loads on an air cargo load could increase risks being at higher altitude, or 4.3 (Dangerous when wet) loads may need extra attention if being carried via sea. 

According to the IATA Dangerous Goods Regulations (DGR), shippers must provide a DG Shipper’s Declaration (DGD) as well as an electronic version (e-DGD). The electronic version is required for digital, safety and accessibility reasons.  

Rachel Jefferies, Editor, FORWARDER magazine