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Hazardous Substances - COSHH Ris Assessment - Overview

Control of Substances Hazardous to Health (COSHH) Regulations 2002

What is a "substance hazardous to health"?

COSHH covers chemicals, products containing chemicals, fumes, dusts, vapours, mists and gases, and biological agents (germs). If the packaging has any of the hazard symbols then it is classed as a hazardous substance.

COSHH also covers asphyxiating gases.

COSHH covers germs that cause diseases such as leptospirosis or legionnaires' disease: and germs used in laboratories.

COSHH doesn’t cover lead, asbestos or radioactive substances because these have their own specific regulations.

This guidance is only aimed at those businesses likely to have chemicals stored or used on their premises.  Other classes of hazardous substances are dealt with in other Quick Guides or require specific professional advice.  

This guide does not apply to those who produce hazardous substances either for supply or as a by product of any process.

How Do I Know if a Substance is Hazardous?

All hazardous substances supplied for sale must carry the Hazard Warning Symbol appropriate to the substance.  They are generally the orange and black symbols found on many common substances or the new international red and white symbols.

What is a MSDS Sheet?

The manufacturer of each substance is obliged to supply a Safety Data Sheet on request which will set out the nature of the hazard, how to store and use the substance, the minimum control measures necessary to control exposure and any necessary personal protective equipment.  The data sheet will also include instructions on how to dispose of the substance safely and without damaging the environment.  The manufacturer’s contact details must be on the product label.

Does COSHH apply to me?

If you have employees (including subcontractors), every part of COSHH applies.

If you have no employees (but you take hazardous substances to other people's premises), all parts of COSHH regulations apply except those about monitoring and health surveillance.

What you need to do - COSHH Risk Assessment:

If your employees are using dangerous substances, you must conduct a COSHH Risk Assessment. Begin by completing a list of all substances used or stored by the business bearing a hazard symbol and then consider the following:


What do you do that involves chemical hazardous substances?
How can these cause harm?
How can you reduce the risk of harm occurring?

Reducing the Risk of Harm at Source

If you cannot replace the substance can you eliminate the hazard at source: for example:


Can you avoid using a hazardous substance or use a safer process – preventing exposure, eg using water-based rather than solvent-based products, applying by brush rather than spraying?

Can you substitute it for something safer – eg swap an irritant cleaning product for something milder, or using a vacuum cleaner rather than a brush?

Can you use a safer form, eg can you use a solid rather than liquid to avoid splashes or a waxy solid instead of a dry powder to avoid dust?

Check your trade press and talk to employees. At trade meetings, ask others in your industry for ideas.

What if you cannot prevent exposure?

If you can’t prevent exposure by eliminating the hazard at source, you need to control it 'adequately' by applying the principles of good control practice:


Design and operate processes and activities to minimise emission, release and spread of substances hazardous to health.

Take into account all relevant routes of exposure – inhalation, skin absorption and ingestion – when developing control measures.

Control exposure by measures that are proportionate to the health risk.

Choose the most effective and reliable control options which minimise the escape and spread of substances hazardous to health.

Where adequate control of exposure cannot be achieved by other means, provide, in combination with other control measures, suitable personal protective equipment.

Check and review regularly all elements of control measures for their continuing effectiveness.

Inform and train all employees on the hazards and risks from the substances they work with and the use of control measures developed to minimise the risks.

Ensure that the introduction of control measures does not increase the overall risk to health and safety.

Control Measures

The objective of COSHH is to prevent, or to adequately control, exposure to substances hazardous to health, so as to prevent ill health. You can do this by:


using control equipment, eg total enclosure, partial enclosure, local exhaust ventilation (LEV);

controlling procedures, eg ways of working, supervision and training to reduce exposure, maintenance, examination and testing of control measures;

worker behaviour, making sure employees follow the control measures.

Changing how often a task is undertaken, or when, or reducing the number of employees nearby, can make an improvement to exposure control.

Control equipment

Control equipment can be general ventilation, extraction systems such as local exhaust ventilation, enclosure, or where the air cannot be cleaned, refuges and respiratory protective equipment

Other control equipment includes spillage capture, decontamination, clean-up procedures and personal protective equipment.

Ways of working

Control through ways of working includes operating procedures, supervision and training.
It includes emergency procedures, decontamination and "permits to work" for tasks such as maintenance. 

It also means testing all control measures regularly – equipment, ways of working and behaviour, to make sure that they work properly.

You should keep records of examinations, tests and repairs to equipment for at least five years. This helps to identify any trends or variations in equipment deterioration.

Worker behaviour

Where control measures are in place it is important to use them properly.  This includes:


wearing any PPE necessary;

using control equipment;

following hygiene procedures;

warning supervisors if anything appears to be wrong.

Control is adequate when the risk of harm is "as low as is reasonably practicable".  This means:


All control measures are in good working order.

Exposures are below the Workplace Exposure Limit, where one exists.

Exposure to substances that cause cancer, asthma or genetic damage is reduced to as low a level as possible.

Exposure Limits

Certain chemicals are subject to Workplace Exposure Limits.  The exposure limit will be set out in the data sheets.

Regard must be had to the workplace exposure limits when determining the adequacy of the control measures.

Hazard Symbols
Legionnaires Disease

Email Us to carry out a COSHH Risk Assessment for you or call us now on (01452) 864 213.

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Control of Substances Hazardous to Health