6th October, 2021

What Substances Does COSHH Cover?

The COSHH regulations cover substances that are hazardous to health. If a substance, in any form, could cause harm to a person, it will need to be assessed under the COSHH regulations. The substances covered by COSHH include chemicals, mixtures, dust, gases, fumes and biological agents.

What Substances Does COSHH Cover? header image

The Control of Substances Hazardous to Health (COSHH) Regulations requires you to control substances that are hazardous to health within your organisation. But what substances does COSHH cover?

Hazardous Substances

It might seem obvious from the name, but the Control of Substances Hazardous to Health (COSHH) Regulations cover hazardous substances. That all seems to make sense, but what makes a substance hazardous?

“hazard”, in relation to a substance, means the intrinsic property of that substance which has the potential to cause harm to the health of a person, and “hazardous” shall be construed accordingly;

The Control of Substances Hazardous to Health Regulations 2002 Interpretation

If the properties of a substance, in any form, could cause harm to a person, then it is hazardous and will need to be assessed under the COSHH regulations. The hazardous substances covered by COSHH include:

It's worth noting here that some very hazardous substances such as asbestos, lead and radioactive substances are covered under their own separate regulations. While these are classified as hazardous substances, they don't come under COSHH as more specific requirements are needed. Other than these special exclusions, all hazardous substances are covered by COSHH.

“substance hazardous to health” means a substance (including a preparation)—

  1. which is listed in Part I of the approved supply list as dangerous for supply within the meaning of the CHIP Regulations and for which an indication of danger specified for the substance is very toxic, toxic, harmful, corrosive or irritant;
  2. for which the Health and Safety Commission has approved a maximum exposure limit or an occupational exposure standard;
  3. which is a biological agent;
  4. which is dust of any kind, except dust which is a substance within paragraph (a) or (b) above, when present at a concentration in air equal to or greater than—
    • (i) 10 mg/m3, as a time-weighted average over an 8-hour period, of inhalable dust, or
    • (ii) 4 mg/m3, as a time-weighted average over an 8-hour period, of respirable dust;
  5. which, not being a substance falling within sub-paragraphs (a) to (d), because of its chemical or toxicological properties and the way it is used or is present at the workplace creates a risk to health;

The COSHH regulations apply to a wide range of substances and mixtures. This includes substances classified as toxic and harmful, those given a workplace exposure limit (WEL), biological agents, hazardous dust, and any dust when present in hazardous quantities. It also includes any other substance where the way it is used or is present at the workplace creates a health risk.

It's important to assess your work and identify which substances could harm your health - you might be surprised. For example, in some workplaces, even water can come under COSHH. Yes, water! It's not a hazardous substance, but if your work means having your hands wet for a long time or frequently wet during the day, this can irritate your skin leading to dermatitis. So the substance isn't necessarily hazardous, but the way it is used or is present at the workplace creates a risk to health.

You can find out more about COSHH in our blog post about why COSHH is important in your workplace.

Identifying Hazardous Substances

The first step in becoming COSHH compliant is to identify the substances used or produced within your business processes. You can't control the risk until you know where the hazards are. Some hazardous substances used within your business will be obvious, but some everyday substances should also be assessed under COSHH.

Often, the labels on bottles and containers will contain warning messages and hazard symbols to indicate the risks. These red diamond pictograms are easy to spot.

corrosive coshh symbol

Where substances are purchased, you can check the safety information on labels and the information provided by suppliers (usually on a safety data sheet, hazard data sheet or other similar product information sheet).

You should request product information from suppliers whenever a new substance is used, as the sheet will contain important information relating to storage, use and the properties of the product. Risk and safety phrases will give you a good indication of how the substance could be harmful to you and your team.

safety data sheet example

Some substances might not be purchased from a supplier, but may be produced as a result of your work processes.

For example, the wood dust produced in a joinery workshop or on a construction site should be assessed under the COSHH regulations. Hardwood dust is classified as a carcinogen (can cause cancer), so is covered by COSHH, and exposure must be minimised and monitored.

To identify substances produced during work processes, carry out a COSHH inspection. Walk around your workplace and look for processes that could produce dust, fumes, vapours, mist or gas, and where skin comes into contact with liquids, pastes and powder.

Your existing knowledge and the knowledge of those you employ to carry out and supervise your business activities should also be used in substance identification. You and your team have specific knowledge of the process and industry experience, and this can be used to help minimise the risks from substances in your workplace.

You can also look for areas of concern from health surveillance, staff complaints and the accident book. Look into any reports of skin burns, dermatitis, nausea, or light-headedness from solvents etc.

Industry knowledge from trade press and data, professional bodies, associations, publications, best practices and HSE guidance material can be used to supplement your in-house knowledge and supplier data. These information sources will often highlight substances that are causing issues in your specific line of work.

When finding which substances you use and produce by your work covered by COSHH, remember to look for:

Once you have identified the substances that are hazardous to health within your workplace, you can then create a COSHH inventory and carry out the required COSHH assessments to minimise the risk and control exposure.


If you need help writing your COSHH assessments, you can start free with the blank COSHH assessment template, or browse the library of ready to use COSHH assessment templates.

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This article was written by Emma at HASpod. Emma has over 10 years experience in health and safety and BSc (Hons) Construction Management. She is NEBOSH qualified and Tech IOSH.

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