Hazard Pictograms & Symbols and What They Mean | EcoOnline

Hazard pictograms and what they mean

Published May 10, 2023

4 minute read

From toxic chemicals to flammable substances, hazardous products can be dangerous to your employees and the environment. It’s important you understand COSHH hazard pictograms or symbols and exactly what they mean to protect your people from short or long-term health hazards and the surrounding environment from harm. These hazard pictograms can keep employees who are working with these substances safe and help you, as the employer, mitigate risks faster with the proper training, controls, and processes in place.  



Keep reading to uncover: 

  • How the GHS simplifies the labelling of chemicals 
  • What do the 9 COSHH hazard symbols mean?
  • What are hazard statements, precautionary statements, and signal words?
  • COSHH next steps 

Chaos to Clarity: How the GHS Simplifies the Labelling of Chemicals

You might be thinking, what is GHS? GHS or the Globally Harmonized System of Classification and Labelling of Chemicals, is an international standard that is used to classify hazards and label hazardous chemicals.

Hazard pictograms must be included on COSHH labels of chemical products as a requirement under the GHS. This standardised system provides a single source of truth so people can fully understand the risks certain substances pose, just by looking at the pictogram.  

What do the 9 COSHH Hazard Symbols Mean?

There are 9 standard hazard pictograms which are used to depict potential hazards worldwide. Each black symbol is depicted within a red diamond with a white background. This is different from the older symbols which were cast against an orange square. 

Old and new COSHH hazard pictograms

You might be thinking, can I still use the old COSHH hazard symbols? The short answer is no. In 2015, the classification system changed to the new Classification, Labelling, and Package (CLP) regulations and in order to stay compliant, you must use the new COSHH hazard pictograms.  

It is your responsibility, as the employer, that all employees are aware of the COSHH hazard symbols and meanings if they work with hazardous substances 

You can find an example of each below:  

Examples of GHS hazard pictograms. Black symbols with red diamond outline as warning.

Now let's get into more detail about exactly what these hazard pictograms mean:

1. Gas under pressure

Gas pressure hazard pictogram

This hazard pictogram indicates gases which are stored under pressure, such as ammonia. The symbol depicts a gas cylinder because this is a common example of something that is found at certain organisations. To protect your employees, make sure these cylinders are always checked to avoid a potential leak.   

2. Dangerous for the environment

Dangerous for the environment hazard pictogram

Showing an environment with chemicals that are harmful to species living in water, this pictogram indicates substances which are dangerous for the environment. Make sure all employees carefully use chemicals with this label and dispose of them in the proper way.  

3. Toxic

Toxic hazard pictogram

The skull and crossbones is a familiar symbol to most of us, as this is used to indicate something that is toxic if ingested, inhaled, or absorbed. Provide the proper training on such chemicals so employees are aware and can take the proper steps to avoid harm.  

4. Health hazard

Health hazard hazard pictogram

In addition to toxic substances, there are several which can cause health hazards irritating the skin and eyes, respiratory tract, and more. This pictogram shows a picture of an exclamation mark. Health hazards are a serious risk to your people, so ensure they all are trained to properly use such chemical products and are given the necessary personal protective equipment.  

5. Flammable

Flammable hazard pictogram

This pictogram shows a flame which means this substance is flammable. Substances that can ignite or catch on fire can be very dangerous to your teams, so provide training on how to deal with these products. 

6. Oxidising

Oxidising hazard pictogram

This pictogram, showing a circle which appears to be on fire, indicates that this chemical product can react with others and release oxidising substances. This is dangerous because such chemicals can cause fires or explosions. 

7. Explosives

Explosive hazard pictogram

Chemical products that have the potential to explode can cause serious risks to your employees. This pictogram shows a bomb exploding, so it’s up to you to provide the necessary training to employees so they know how to handle such a substance.   

8. Serious health hazard

Serious hazard to health hazard pictogram

Certain substances have the potential to cause serious damage to the health of your people. This pictogram, showing someone with internal damage, is usually found on chemical products that can affect internal organs, fertility, and more. 

9. Corrosive

Corrosive hazard pictogram

Chemicals that can be extremely harmful to your skin or objects around you are labelled corrosive. This pictogram depicts skin and specific materials that are damaged because of this substance. All employees must learn how to properly use such products and be given the necessary PPE.  

What are Hazard Statements, Precautionary Statements, and Signal Words?

In addition to hazard pictograms, COSHH labels and safety data sheets can also include hazard statements, precautionary statements, and signal words. Combined, these will help paint a clearer picture of the hazardous substance and how to reduce risk on site.  

Let’s break down what each of these means: 

  • Hazard statements: A hazard statement provides more information on the hazard within the substance. Phrases like, may cause irritation or toxic if swallowed, are an example of a hazard statement.  
  • Precautionary statements: A precautionary statement explains how to minimise health hazards which may arise from exposure to a hazardous substance when interacting with it. An example of this would include wearing specific types of PPE.  
  • Signal words: Under CLP regulations, two signal words may appear on COSHH labels: Danger or Warning. If the substance may result in a serious hazard, the signal word Danger will appear, while if it is not as serious the signal word Warning will be written.  

Below is an example of section two found within a safety data sheet, which includes a hazard pictogram, signal word, and hazard statements: 

An image of section 2 within an SDS

It’s important that you and your teams are aware of all these statements before working with a specific substance.  


Your next steps

Now that you know all about hazard pictograms and what they mean, you can give yourself a huge chemical safety pat on the back! If you're ready to explore more, we’ve chosen three resources below that you might find useful.

  1. Discover how to label your way to success with effective CLP Labelling compliance

  2. Dive into the key points that you need to know about COSHH and get answers to key questions

  3. Or, access our downloadable GHS / CLP Pictograms Poster and put your knowledge into action

Author Dina Adlouni

Dina is a Content Marketing Manager at EcoOnline who has been writing about health and safety, ESG and sustainability, as well as chemical safety for the past four years. She regularly collaborates with internal subject matter experts to create relevant and insightful content.

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