BY Benedikt Schrage IN Industry knowledge

GHS hazard symbols: Which pictograms identify hazardous substances?

The Globally Harmonised System (GHS) of the classification and labelling of chemicals defines international standards for the classification and labelling of hazardous substances and chemical mixtures. Its aim is to protect the public's health and the environment by requiring clear identification of hazardous properties on chemical product labels and regulatory packaging.

The GHS hazard symbols on labels consist of a red-edged hazard pictogram, a signal word such as ‘Danger’ or ‘Warning’, and hazard and safety phrases (H and P sentences). This compulsory labelling plays an essential role in preventing risks in the workplace, protecting consumers and enabling emergency services to intervene in the event of an incident involving hazardous chemicals.

What is GHS?

The Globally Harmonised System (GHS) of the classification and labelling of chemicals is a global standard that defines uniform rules for the classification, labelling and packaging of hazardous substances and mixtures. It forms the regulatory basis for many countries, including the UK's Control of Substances Hazardous to Health (COSHH) regulations. In the European Union, the GHS is implemented through the CLP (Classification, Labelling and Packaging) regulation, ensuring the standardisation of GHS hazard symbols on chemical labels and packaging.

The main objective of the GHS is to eliminate international divergences in the classification of hazardous chemicals, while enhancing workplace safety, health and environmental protection, and the safe transport of dangerous substances.

Products containing hazardous substances are found in many industrial sectors, such as metallurgy, construction and the chemical industry. The medical sector and cosmetics inductry also adopt GHS hazard symbols in line with international regulations for labelling medicines and other products.

The importance of GHS labels

GHS labelling for chemical products is essential to safety in the workplace. It provides information on the hazards and precautions to be taken, thereby reducing the risks involved in handling hazardous substances.

Employers and workers use GHS labels to identify the necessary protective measures before using a product. In logistics and transport, they facilitate the storage, handling and disposal of chemical substances.

Emergency services can quickly assess health and environmental risks in the event of an emergency, thanks to GHS hazard pictograms. Even witnesses to an accident can pass on crucial information to the emergency services.

For consumers, GHS labels on chemical products help prevent accidents in the home by indicating the precautions to be followed when storing, handling and disposing of hazardous products.

Additional safety measures: safety data sheets (SDS)

In addition to GHS labels on chemicals, the standardisation of Safety Data Sheets (SDS) is a key element of the GHS system. These sheets provide detailed information on

The properties of chemical substances
Precautions for safe handling and storage
Emergency measures in the event of an incident (first aid, fire-fighting, leak management).

The standardisation of GHS SDS not only facilitates the international trade of chemicals, but also ensures the protection of public health and the environment.

Identification of hazardous substances

All hazardous chemicals are labelled according to a standardised scheme that clearly identifies the risks. The GHS hazard symbols on labels follow precise rules:

A red racket (a red-edged diamond with a white background), containing one of nine specific GHS pictograms.

A GHS code, consisting of the letters ‘GHS’ followed by a number between 01 and 09, indicating the hazard category.

An H (Hazard statement) code, beginning with ‘H’ followed by 2 to 4 digits, detailing the exact type of hazard.

A signal word, such as ‘Danger’ or ‘Caution’, in the official language of the country concerned.

Detailed safety information, including the composition of the product, specific risks, recommended precautionary measures and the contact details of the manufacturer or distributor.

These elements form a regulatory GHS pictogram, ensuring rapid identification of chemical hazards. A similar system is used for dangerous goods, where the nine hazard classes are based on the same GHS symbols, but are differentiated by distinct colours for even quicker recognition.

What do the GHS symbols mean?

The regulations on hazardous substances identify 28 categories of dangerous chemicals. Each of the nine GHS pictograms represents several hazard classes, grouping together various risks to health, safety and the environment.

Symbol	Description	Hazard Class	GHS Code	Signal Word
	Exploding Bomb	Explosive substances/mixtures and articles containing explosives. Partially self-reactive substances/mixtures. Partially organic peroxides.	GHS01	Danger
	Flame over Line	Flammable gases/liquids/aerosols/solids. Pyrophoric liquids/solids. Partially self-reactive substances/mixtures. Self-heating substances/mixtures. Substances/mixtures that develop flammable gases upon contact with water. Partially organic peroxides.	GHS02	Cell
	Flame over Circle	Oxidising gases/liquids/solids	GHS03	Danger
	Gas Cylinder	Compressed/liquefied/refrigerated liquefied/dissolved gases	GHS04	Warning
	Two Test Tubes, Damaged Surface and Hand → Corrosive	Corrosive to metals. Skin/eye irritating/damaging substances/mixtures	GHS05	Depending on the specific hazard: Danger or Warning
	Skull and Crossbones	Acutely toxic substances/mixtures (Categories 1-3)	GHS06	Danger
	Exclamation Mark	Acutely toxic substances/mixtures (Category 4). Skin irritants (Category 2). Skin sensitising substances/mixtures. Target organ toxic substances/mixtures (single exposure, Category SE3). Ozone-depleting substances/mixtures	GHS07	Warning
	Human Torso	Respiratory sensitising substances/mixtures. Germ cell mutagens. Reproductive toxic/carcinogenic substances/mixtures. Target organ toxic substances/mixtures (Categories SE1, SE2 – single exposure). Target organ toxic substances/mixtures (Categories RE1, RE2 – repeated exposure). Aspiration hazardous substances/mixtures	GHS08	Depending on the specific hazard: Danger or Warning
	Dead tree and dead fish	Substances / mixtures / products hazardous to aquatic environments (acute / chronic)	GHS09	Depending on the exact nature: Warning or no signal word

The UFI code in the GHS

EU Regulation 2017/542 introduced further changes in 2017. Since then, GHS labels must also include the UFI code (Unique Formula Identifier).

The UFI code is a 16-digit combination of letters and numbers that uniquely identifies a hazardous substance. This facilitates communication with poison centres in particular, as the code provides quick information on the trade name, composition, colour and toxicology.

What is the difference between GHS and CLP?

The CLP regulation (Regulation No. 1272/2008) was adopted by the European Union in 2008 to implement the Globally Harmonised System (GHS) within its territory. It establishes rules for the classification, labelling and packaging of hazardous substances, thereby guaranteeing the protection of human health and the environment.

In addition to the use of GHS pictograms and standardised wording on GHS labels, the CLP regulation imposes specific standards for the packaging of hazardous chemicals. It also requires importers and downstream users to provide authorities with detailed information on solutions presenting health risks.

The CLP regulation also plays an economic role in promoting competitiveness and innovation in the European chemicals sector. By establishing a harmonised regulatory framework, it facilitates trade in the chemical industry within the EU. The regulation is based on former European directives, in particular:

Directive 67/548/EEC (Dangerous Substances Directive)
Directive 1999/45/EC (Dangerous Preparations Directive)

These directives have been replaced by the CLP Regulation, establishing a modernised and unified regulatory basis for the classification and labelling of chemicals across Europe. This simplified framework not only facilitates international trade, but also enhances the protection of workers, consumers and the environment.

History of the GHS

The idea of a unified global system for the classification and labelling of chemicals was introduced at the Earth Summit on Sustainable Development in 1992. It led, in 2002, to the creation of the Globally Harmonised System (GHS), which standardised hazard symbols, labels and Safety Data Sheets (SDS).

In the European Union, the GHS was implemented via the CLP Regulation in 2008, which came into force in 2009 and gradually replaced all national regulations by 2015. Since then, the same rules for classifying, labelling and packaging hazardous substances have been applied across the EU, ensuring greater consistency and safety in the trade and use of hazardous chemicals.

What is a hazardous substance?

Dangerous substances present risks because of their chemical and physical properties, particularly when handled incorrectly. They fall into three main categories:

Pure substances: Individual chemical elements (e.g. hydrogen, H) or compounds made up of at least two elements (e.g. water, H₂O).
Mixtures: Combinations of two or more pure substances, which may exist in different forms such as fumes, mists or emulsions.
Finished products: Manufactured products containing substances or mixtures - some are considered unregulated under EU laws, while others are classified as hazardous.

Hazardous substances can present risks to health, the environment or physical safety. This may include hazards related to flammability, explosiveness or harmful effects on living organisms and materials. These risks are not limited to the initial state of the product, but also concern potential hazards during manufacture or use.

To simplify, the terms ‘dangerous substances’ and ‘chemicals’ will be used in a general way in the remainder of this article. A more precise distinction between pure substances, mixtures and finished products will only be made where this is necessary for understanding.
Routes of Exposure to Hazardous Substances
Hazardous substances can enter the human body through various means:

Inhalation: Inhalation of gases, vapours, mists or dusts.
Dermal exposure: Absorption through the skin or mucous membranes via direct contact.

Depending on the route of exposure, the health risks vary, requiring appropriate protective measures such as wearing a respiratory mask, protective gloves or other safety equipment.

Examples of hazardous substances

The definition of a hazardous substance covers a wide range of chemical and physical properties. In the UK, the Control of Substances Hazardous to Health (COSHH) regulations are the main regulatory reference for these substances. It sets out the rules for labelling hazardous substances using chemical and GHS labels, as well as standards for compliant packaging.

COSHH requires employers to identify and assess the risks associated with hazardous substances in the workplace, hazardous substances under COSHH include:

Substances that are classified as hazardous to health, according to the CLP (Classification, Labelling, and Packaging) regulations.
Explosive compounds, which present an explosion risk under certain conditions, regulated separately under the Explosives Regulations.
Products whose manufacture or use generates hazardous substances, such as fumes, dusts, and vapors.
Substances that may not be classified as hazardous under CLP but could still pose a risk to safety or health in the workplace.
Chemical products subject to an occupational exposure limit (OEL) or workplace exposure limit (WEL), which defines safe exposure thresholds in the workplace.

Hazard classes according to the GefStoff

The Hazardous Substances Ordinance differentiates between hazardous substances according to their hazard classes:

Physical hazards (e.g. flammable, explosive or self-reactive substances)
Health hazards (e.g. carcinogenic, toxic or corrosive substances)
Environmental hazards (e.g. substances hazardous to water)

This classification determines which protective measures are required and which labelling is prescribed on packaging and safety data sheets.

Legal consequences of violations of Control of Substances Hazardous to Health (COSHH) regulations

In the UK, Control of Substances Hazardous to Health (COSHH) regulations have clear rules for the safe handling of hazardous substances. Depending on their severity, violations can be punished as administrative offences or criminal offences. This applies, for example, to:

Missing or incorrect labelling of hazardous substances,
Inadequate protective measures for employees,
Non-compliance with storage and transport regulations,
Failure to comply with occupational exposure limits for hazardous substances.

Consistent compliance with the COSHH not only ensures legal safety, but also protects people and the environment from potential hazards.

Is there a difference between dangerous substances and dangerous goods?

Anyone interested in GHS hazard symbols and the labelling of 'dangerous substances' will inevitably come across the term 'dangerous goods'. Although the two concepts seem similar, there are some notable differences:

Dangerous substance: Presents a danger during its manufacture, storage or use.
Dangerous goods: Represents a risk during transport.

This means that a chemical product is not necessarily a dangerous good, but may become one in certain circumstances. For example, lighter fluid is not a dangerous good when stored, but when transported in large quantities by lorry, it becomes subject to regulations on the transport of dangerous goods.
Conversely, some products are classified as dangerous goods without being considered as dangerous substances on a day-to-day basis. This is the case with lithium-ion batteries, which, because of the risk of thermal runaway, are subject to strict regulations for air transport.

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The effects of the GHS regulation on packaging

The CLP Regulation (EC n°1272/2008) sets out the rules for the classification, labelling and packaging of hazardous substances and mixtures within the European Union. It applies to all packaging required for the direct use of a product, whether outer, inner or intermediate packaging. GHS (Globally Harmonized System) labels must be affixed to all such packaging.

Protective and consolidation packaging that is used exclusively for transport or storage, however, is not subject to the labelling requirements of the CLP Regulation. This means, for example:

Direct outer packaging (secondary packaging): A battery that is classified as a hazardous substance must be labelled with the appropriate hazardous substance labels in its direct secondary packaging.
Transport packaging: A cardboard box that combines several such battery packagings for transport is considered protective packaging and is not subject to the CLP labelling regulations.

Other CLP packaging requirements

Packaging size: Small containers under 125 ml may be subject to simplified labelling obligations in which not all hazard statements are required.
Obligations of distributors: Manufacturers, importers and distributors must ensure that their packaging is labelled correctly and in good time.
Multilingual labelling: Hazardous substance labels must be available in the official language of the Member State in which the product is sold.
Safety requirements: Child-resistant closures and tactile warning signs are required for certain substances to better protect consumers.

Vigilance from packaging companies

As not all types of packaging are affected by these regulations, the packaging industry does not have to completely reorganise its processes. Nevertheless, it is essential to familiarise yourself with the current directives. Companies in the packaging industry are obliged under the CLP Regulation to ensure a transparent flow of information with their customers through appropriate labelling of hazardous substances.

It is therefore essential for companies to check in advance that their packaging complies with GHS regulations, to avoid any risk of non-compliance.