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Hazardous Substances

You have a responsibility to control and reduce the risks to the health of your employees arising from the use of substances hazardous to health.

These responsibilities were set out in detail in the Control of Substances Hazardous to Health (CoSHH) Regulations 2002 (as amended). In 2005 these Regulations were changed in order to:

  • Make it easier and less burdensome for employers to understand the occupational exposure limit (OEL) approach and thus aid implementation 
  • Overcome problems such as the lack of a comprehensive approach and the perception that the former occupational exposure standard (OES) was a "safe" limit 
  • Improve the approach to and process for setting limits 
  • Ensure compatibility with the EU process for setting exposure limits

Despite the seemingly major changes much remained unchanged and employers who were already complying with the regulations did not have to undertake much, if any, work in order to comply with the updated regulations.

As always, it is best to act before any effect on health occurs and a first step in identifying hazardous substances is to check the labels of products and read the material safety data sheets (MSDSs) provided by the supplier or manufacturer.

Assessing the Risks:

Once potentially harmful substances have been identified an assessment will need to be carried out.

A COSHH assessment evaluates the risks to health from a substance and identifies the action needed to eliminate, reduce or control those risks. You have responsibility for carrying out assessments, but the task can be delegated to somebody suitable. Either way, they need to understand the COSHH Regulations and have access to the Approved Code of Practice and any other documents.

For more information about the HSE's assessment visit*
When carrying out an assessment, it is important that managers and employees' representatives are consulted and understand the processes and the risks involved. Points to consider in the assessment include:

  • The work routines; how people are exposed and the lengths of time that they are exposed. 
  • The effects of the substances if they were to cause harm, both acute and chronic. 
  • The control measures that are currently in place and their effectiveness.

The risks should be evaluated and conclusions reached on what is needed to adequately control the risks. Guidance on best practices to minimise exposure can be obtained from manufacturers and suppliers, the HSE and any other authoritative sources.

You may find that many of the measures necessary to control the risks are already in place, but you should still record the conclusions of your assessment. You also need to review the assessments from time to time to check that they are still valid.

The employer will also need to keep a written record of the assessment to enable it to be reviewed in the future.

Taking Control:
The assessment will indicate the extent of the risks and identify the control measures required. To control the health risks presented by SHHs, the most effective control measures must be considered first. The general hierarchy of control measures is as follows:

Avoid exposure by

  • Eliminating the substance from the workplace 
  • Substituting the substance with a less hazardous one 
  • Total enclosure of the process, thus separating the substances from the person 
  • Enclosure and provision of local exhaust ventilation (LEV) 
  • Good general ventilation 
  • Personal protective equipment such as respirators gloves and goggles

Other measures might include:

  • Prohibiting eating, drinking and smoking in the work area 
  • Providing washing facilities and facilities for changing clothes 
  • Regular cleaning of the workplace 
  • Providing the means for safe storage and disposal of substances and waste

The New Approach:

The new approach can be summarised as follows:

  • Single type of OEL - the Workplace Exposure Limit (WEL) 
  • An emphasis on applying/following good practice 
  • Provision of advice on control strategies 
  • Linking of WELs to good practice advice 
  • Transfer of all Maximum Exposure Limits (MELs) and the soundly based OESs (in excess of 100) to the new system

Whereas the "old approach" established that legal compliance was achieved by defining adequate control as being compliance with MELs and OESs the new Regulations revoke that duty. Instead a new duty of "adequate control" is defined which involves applying the principles of good practice. This duty exists for all substances whether or not they have an exposure limit. For those substances that have been given an exposure limit there is an additional duty not to exceed the workplace exposure limit (WEL). The new approach also avoids any difference in approach relating to the route of exposure. Whereas in the past compliance was focussed on control of inhalation the new approach in COSHH 2004 applies irrespective of whether there is a risk by inhalation, ingestion or through dermal contact.

The Principles of Good Practice:
These are set out in schedule 2A of the new Regulations and include the following. Examples of the application of the principles are given in each case:
Designing and operating processes and activities to minimise the emission, release and spread of SHHs

Example: Carrying out chemical reactions that might generate harmful substances in closed vessels fitted with extraction; Fitting machines that generate dust with suitable extraction
Taking into account all routes of exposure

Example: Ensuring that all possible exposures are considered - ingestion, inhalation and skin exposure
Controlling exposure by means that are proportionate to the health risk

Example: The approach for controlling a toxic dust would be much stricter than that for a low toxicity substance thus a simple cartridge respirator may be suitable for a nuisance dust whereas a powered respirator or breathing apparatus might be needed for more toxic substances (if LEV had not been installed)
Choosing the most effective and reliable control options to minimise the escape and spread of SHHs

Example: Whilst an extraction system might contain dust generated during mixing of dry ingredients the use of premixed liquid components removes the risk entirely and will also eliminate the need for routine examination and maintenance
Providing, in combination with other measures suitable respiratory protective equipment (RPE) if adequate control of exposure can not be achieved by other means

Example: Selecting the most effective types of respiratory equipment (RPE) for the task e.g. half-face masks, breathing apparatus etc and then involving employees in the final selection of the equipment to be used
Checking and regularly reviewing all elements of control measure

Example: Ensuring that ventilation equipment receives a regular inspection and examination to confirm that it is still in good working order; ensuring that there is regular inspection of respiratory equipment and that consumables such as cartridges are replaced as necessary
Providing information and training to all employees on the hazards and risks associated with the substances with which they work and the use of control measures

Example: Obtaining Material Safety Data Sheets (MSDS) from suppliers, and then carrying out an assessment of local use and communicating the results to employees; ensuring that employees are aware of the importance of closing doors and entries to enclosed spaces and vessels to ensure effective operation of extraction equipment
Ensuring that the introduction of control measures does not increase the overall risk to health and safety

Example: The installation of an extraction hood may make it difficult to add bagged goods to a reactor vessel

CoSHH Essentials
The COSHH Essentials website will play a greater role in the new regime. It will be a powerful source of guidance and advice, delivering:

  • Task specific control advice 
  • Control guidance sheets for dusts and fumes 
  • Information for specific industries

The primary question on entering the COSHH Essentials website will be whether the substances have a WEL. If so, the WEL determines the hazard group and the appropriate action to be taken. In the absence of a WEL the R phrase will perform the same function. The next revision of EH40 will quote the hazard group for each WEL.

Next Steps

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Please Note
This document contains general information and guidance and is not and should not be relied on as specific advice. The document may not cover every risk, exposure or hazard that may arise and Aviva recommend that you obtain specific advice relevant to the circumstances. AVIVA accepts no responsibility or liability towards any person who may rely upon this document.

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