This toolkit provides step-by-step guidance for managing the risks from hazardous substances.

What is COSHH?

COSHH stands for Control of Substances Hazardous to Health. Under the Control of Substances Hazardous to Health Regulations 2002, there is a duty on employers to prevent and control exposure to hazardous substances that can cause ill health or injury to their employees and those who may come into contact with their activities.

The COSHH Regulations also place a duty on the employer to implement a health surveillance programme for those who are exposed to specific hazardous substances and to keep medical records for a certain amount of time.

What does COSHH not apply to?

The COSHH Regulations do not cover lead, asbestos or radioactive substances as these are covered by their own regulations.

Nor does COSHH cover substances and mixtures which are hazardous solely because of their physical properties, ie substances and mixtures that are:

  • hot, eg molten metals

  • cold, eg liquid nitrogen

  • pressurised, eg gas cylinders

  • flammable, eg solvents

  • explosive.

What form do hazardous substances take?

Hazardous substances may be:

  • chemicals

  • products containing chemicals

  • fumes

  • dusts

  • vapours

  • mists

  • nanotechnology

  • gases

  • biological agents (eg bacteria, viruses, fungi, parasites).

Hazardous substances can enter the body through ingestion, injection, inhalation or absorption through the skin. The effects of exposure can vary greatly: from mild irritation to, sometimes, death. Effects can be acute (such as a one-off gross exposure as a result of a spillage) or chronic (day-after-day low-level exposures, which have an effect only after months or years of exposure). The degree of exposure to a substance during an activity is critical.

How to Control Substances Hazardous to Health

1. Draw up an inventory of hazardous substances

The first step is to identify what hazardous substances are present, or are likely to be present, in the workplace, or to be encountered during working operations. Use the Hazardous Substances Inventory Record.

2. Conduct a risk assessment

The detail of the risk assessment depends largely on the nature of the work process, the associated hazards and those who are at risk of exposure. This COSHH — Risk Assessment summary can help.

Select competent personnel to complete the assessment exercise but ensure that this is not done in isolation from those who actually use and handle the substances as a part of their work.

3. Identify any additional control measures required

Start by comparing existing control measures against recognised management standards such as industry sector best practice, your own in-house policy and guidance, government advice and any necessary specialist advice and guidance. See also Principles of Good Practice.

Following the risk assessment, decide whether exposure needs to be further prevented or controlled using the hierarchy of control. Risk can be reduced by procedural controls such as reducing the number of workers exposed to the hazard, reducing the duration of exposure and implementing good personal hygiene standards.

Ensure that control measures are used and maintained. When hazardous substances are used in the workplace, it is imperative that the safe systems of work in place to prevent harm are reviewed often, equipment is tested including personal protective equipment (PPE), accidents and incidents are reported and investigated and training is given to those who manage employees who use the substances and the employees who use them.

4. Consider whether to monitor exposure

Monitoring is the measurement of an employee’s exposure to substances hazardous to health and should be carried out if:

  • the assessment indicates there could be serious risks to health if control measures fail or do not work properly

  • exposure limits might be exceeded.

Monitoring is not necessary if the employer can show exposure is prevented or adequately controlled by other means of evaluation. However, monitoring must be carried out if employees are exposed to certain substances specified in COSHH.

For details see Exposure Monitoring in the Occupational Exposure Limits topic.

5. Consider whether health surveillance is necessary

Health surveillance aims to detect at an early stage adverse changes which may be attributed to exposure to substances hazardous to health, or to help evaluate the suitability of control measures or the evaluation of hazards.

Health surveillance is appropriate if:

  • there is exposure to a substance known to damage health in some particular way

  • there are valid ways to detect the disease or condition

  • an employee is found to be suffering from an illness or infection which is suspected to be the result of exposure at work (in this case other employees who have been similarly exposed should be placed under suitable health surveillance until it is established that they are not affected)

  • it is reasonably likely that damage to health may occur under the particular conditions at work.

6. Establish emergency measures

A plan will need to be implemented for those events where exposure to a hazardous substance goes beyond the risks associated with normal day-to-day work.

Also, employers are required to prepare plans and procedures in case of an accident or emergency. See the Emergency Management topic for guidance, model policies, factsheets and forms.

7. Provide suitable training

Make sure employees have the necessary training to work with hazardous substances safely and without harm to themselves or others.

Training should be proportionate to the risk. The COSHH assessment will give indication to the level and depth of training required.

Training should be mandatory for those who use such substances as well as those who manage them, to ensure they too understand the risks to employees. Training must also be refreshed at adequate intervals. Use the Hazardous Substances Training Record.

The COSHH Training Presentation can be downloaded and adapted to suit your organisation’s needs.

8. Keep records

Under COSHH, records of maintenance, examination and testing of control measures must be kept for at least five years. This includes records of the maintenance of engineering controls such as local exhaust ventilation systems (LEV) and respiratory protection.

Exposure monitoring records must be kept for five years if not related to specific employees. Where they do relate to specific employees, they must be kept for 40 years. This includes results of health surveillance which must also be kept confidentially. See the Factsheet: How long to keep health and safety records in the Records and Record Keeping topic.

Keeping records assists in examining the effectiveness of control measures as well as providing evidence for potential injury claims.

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Last reviewed 2 March 2021