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Hazard Symbols and Meanings – Useful Guide

Hazard symbols and their meanings provide useful information in a visual image form, to alert people of the presence of a hazardous chemical that could harm people or the environment. Most of the images in this guide cover what is known as the GB CLP Regulation, linked to the European Regulation (EC) No 1272/2008.

These regulations are also related and linked to the United Nations ‘Globally Harmonised System’ (GSH) for the Classification, Labelling and Packaging (CLP) of chemical substances. For more please see the useful HSE CLP guide and for more detail.

The main hazard symbols can be seen in the image below, in the 3 x 3 grid on the left and we will explain them, and some other interesting and relevant safety symbols in this article (such as the two in the bottom right corner). Some of these hazard symbols are relevant to things like mould removal services and treatments, which we are experts in, especially mould in homes and businesses locally.

Hazard Symbols Meanings – Explained

Hazard Symbols Meaning
Hazard Symbols Meaning – Explained

These red and black symbols replaced older symbols (known as CHIP symbols – Chemicals Hazard Information and Packaging for supply) that were orange and black, which have been phased out, like the ones shown below:

Hazard Symbols Orange
Hazard Symbols Orange (previous)

These CHIP symbols were replaced in June 2015 – see the HSE website for more details. As you can see, there are some similarities with the newer versions which are aligned to global standards for consistency across the world.

Chemical Hazard Symbols and COSHH UK

The HSE page also mentions the related subject of COSHH which is the Control of Substances Hazardous to Health Regulations, which can include chemicals as well as products containing chemicals, fumes, dusts, vapours, mists, nanotechnology, gases, asphyxiating gases and biological agents (germs) – including those that can cause diseases. Exposure risks to these could be via – skin contact (or puncturing the skin), contact with eyes, swallowing and breathing in.

Different items covered by COSSH will likely have WELS (Workplace Exposure Limits) more on this later. In the meantime, we have another interesting article about Christmas Fire Safety Tips which includes electrical fires.

Importantly, COSHH does not cover lead, radioactive substances or asbestos. For more information about asbestos, see our asbestos testing and removal page and our recent article about artex and possible asbestos.

We will now look at each of the 9 hazard symbols and meanings one by one, in each of the cases below we show the symbol on the left with the name of it to the right. However, in most instances the logo will not have that description shown the same so it is very useful to know them from sight. We discuss hazard symbols in our guide to fluorescein.

It is also worth mentioning that, when these logos appear on cleaning chemical labels for example, like those we use as part of our specialist cleaning services, it will likely have additional information than just the logo so do check that and also the relevant safety data sheets (SDS) plus instructions for that product.

Hazard Symbol Explosive
Explosive Hazard Symbol

Explosive Hazard Symbol

The symbol for an explosive hazard is an image of an exploding bomb and refers to reactive substances that could explode when dry or through exposure to heat or a flame, possibly causing property or severe injury to a person.

Hazard Symbol Flammable
Flammable Hazard Symbol

Flammable Hazard Symbol

The symbol for a flammable hazard is an image of a flame to signify items that may catch fire in contact with air or an ignition source or other flame. It includes “Flammable gasses, flammable liquids, flammable solids, flammable aerosols, organic peroxides, self-reactive, pyrophoric, self-heating, contact with water emits flammable gas”. Such solutions are advised to be kept stored in fire-resistance storage cabinets.

On the subject of flammable materials, we have an article about fire classification and a similar useful guide, with explanatory diagrams about the fire triangle components.

Hazard Symbol Acute Toxicity
Acute Toxicity (severe) Hazard Symbol

Acute Toxicity Hazard Symbol

The symbol for acute toxicity is a skull and crossbones which indicates a substance that can cause serious health risks or, possibly even death if it is ingested, inhaled or if it penetrates your skin. This is an example of something that, with the correct corresponding PPE (Personal Protective Equipment) can help mitigate the risk.

Hazard Symbol Oxidising
Oxidising Hazard Symbol

Oxidising Hazard Symbol

The symbol for oxidising hazards is a circle with a flame on top of it and is for substances that can react with other substances / materials that may cause explosive damage, heat, fire or even damage to living tissues.

Hazard Symbol Corrosive
Corrosive Hazard Symbol

Corrosive Hazard Symbol

The corrosive hazard symbol is a picture of two test tubes spilling or pouring over a material or flesh (shown as a hand) and indicates things that can cause serious skin damage (including burns) and eye damage if it comes into contact with them. This is another one where appropriate PPE can help and, in the case of accidental exposure, the correct first aid / medical support is very much relevant. This can include things like strong acids or alkalines.

Hazard Symbol Environment
Harmful to Environment Hazard Symbol

Harmful to Environment Hazard Symbol

The symbol for chemicals that are hazardous to the environment shows a tree and (apparently) dead fish. These substances can cause immediate or longer term damage to the environment (plants and animals – including fish) including having toxic effects on aquatic life. Amongst other things, safe disposal is key for these.

Hazard Symbol Gas Under Pressure
Gas Under Pressure Hazard Symbol

Gas Under Pressure Hazard Symbol

The symbol for gases under pressure shows a gas cylinder (or bottle) and can include gases, liquified gases etc. The risk from these not only comes (potentially) from the contents but moreover the fact that they are pressurised. In fact, in some instances the gas could be inert. We have more on this later.

Hazard Health Exclamation
Health Hazard Exclamation Mark Symbol

Health Hazard Symbol

The symbol for health hazards is an exclamation mark, showing things that can cause harmful skin irritation, dangerous / serious eye irritation, harm to the ozone layer and even acute toxicity. This can be from biohazards too, which we will discuss further later as there is a symbol people often associate with that too.

Serious Health Hazard
Serious Health Hazard Symbol

Serious Health Hazard Symbol

The symbol for serious health hazards is a human head and shouders with a star-shaped internal health hazard symbol. It can include “Respiratory sensitiser, mutagen, carcinogen, reproductive toxicity, systemic target organ toxicity, aspiration hazard” – things that can cause long term, very serious damage to your health.

Biohazard Risk Hazard Symbol

Biohazard Symbols

The symbol above is used to indicate a biohazard or biological hazard and can cover a number of things which can pose a threat to living organisms, including human life. This can include viruses (such as Covid-19 / Coronavirus) or toxins. There are a number of categorisations and levels of this which can be seen and explained in more detail on the Biological Hazard Wikipedia page.

We offer a Covid Cleaning Service (or other similar viruses) and biohazard cleans to people.

Hazard Symbol Compressed Gas
Compressed Gas Hazard Symbol

Compressed Gas Symbol – Class 2

This is not one of the red and white CLP Hazard Symbols but it is something you might see. There are different variants but this one above is for ‘Class 2‘ which has sub-classes of non-flammable or non-poisonous compressed gas. In our case, we sometimes use tracer gas for our water leak detection service. Tracer Gas is generally 5% Hydrogen and 95% Nitrogen.

Hazard Symbols Precautionary Statements

You may often see hazard symbols with precautionary statements alongside them to help mitigate the risk from the relevant hazards, examples could include:

  • Flammable liquid – keep away from heat, sparks or flames
  • Respiratory related hazards – ensure good ventilation and wear respirator
  • Corrosive hazards – wear protective gloves and eye protection
  • Pressurised gas hazards – store in a well ventilated cool place

We talk about safety in our guide to when you have a washing machine leaking. And also our really informative guide to air quality readings.

We hope you found this guide to hazard symbols useful. As we said above, it is useful to familiarise yourself with these hazard symbols, even if it is not something you use in your work, you could have a situation where you come into contact with these signs so be alert and take care when you see them.

If you think you might have a water leak and want help and advice from our friendly, experienced and local team – get in touch with us and and we will help and advise you.

We’re experts in dealing with many types of hazardous situations relevant to hazard symbols, including crime scene cleaning York and the Yorkshire Coast area. So if you need help with these, contact our friendly team to arrange for help and guidance. We also deal with water leaks in Yorkshire homes and businesses, including water leak detection in York.

At Rainbow Restoration – York & Yorkshire Coast we’re experts in Water Damage Restoration, so if you need help getting your property back to normal after a leak or flood, get in touch with our team.

What do hazard warning symbols look like?

Hazard Symbols Warning

There are 9 main hazard warning symbols that are all red diamond borders with white backgrounds and black symbols on them to indicate which warning it is portraying. They show symbols for explosives, flammable materials, acute toxicity, oxidising, corrosive, hazardous to the environment, gas under pressure, health hazards and serious health hazard symbols, each with a different meaning.

What do hazard warning symbols mean?

Hazard Symbols Warning

Hazard warning symbols are present to indicate substances, in particular chemicals that present a risk, including to harm human health. There are 9 main symbols on the GB CLP (Classification, Labelling and Packaging) pictograms in the shape of a diamond with a red border and black symbols on a white background. They replace older (orange) symbols in the UK which have been phased out so as to be consistent with global standards for hazard symbols.

What are the 9 hazard symbols?

Hazard Symbols Warning

The 9 hazard symbols and their meaning are – an exploding bomb (for explosives), a flame (flammable materials), skull and crossbones (acute toxicity), a circle with flames on top (oxidising), test tubes dripping on a substance and hand (corrosive), a dead tree and fish (hazardous to the environment), gas cylinder (gas under pressure), exclamation mark (health hazards) and a head and shoulders image with a star-like internal damage symbol (indicating serious health hazard symbols)

What are Workplace Exposure Limits – WELS?

Hazard Symbols Warning

Workplace Exposure Limits (abbreviated to WELS) are limits set on the amount of exposure limits applied to certain hazardous substances under COSHH. This can be from breathing in, coming into contact with skin or eyes, through puncturing the skin or by swallowing. They exist to protect people both in the short and long term to protect people’s health. This is usually displayed with the details of the product and covered as part of the Material Safety Data Sheet (MSDS).

How do you explain what a hazard meaning is?

Hazard Symbols Warning

The meaning of a hazard is something with the potential to cause harm, injury or illness. In extreme situations a hazard can have the potential to cause death. This is why understanding hazard meanings, such as those on chemicals, can be critical to good health and safety practices. In identifying and understanding hazards, as part of a risk assessment, you can help to mitigate the associated risks (for example with PPE).

Leak Detection Logo
Leak Detection Logo