Guidance Note 6 – Control of substances hazardous to health (COSHH)

This Guidance Note gives practical information about COSHH.

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A completed sample template has been included in Appendix 1 and a blank template in Appendix 2. If you wish to use the template in Appendix 2 to construct your own documents, you must ensure that all references to Alcumus SafeContractor Accreditation have been removed and the final documents are clearly incorporated into your existing safety management system.

Legal obligations

The Control of Substances Hazardous to Health Regulations 2002 (COSHH) (as amended) provides the main legislative framework for the control of hazardous substances in the workplace. Legionella bacteria (which causes Legionnaires’ disease) is covered by these regulations, and has its own approved code of practice.

Hazardous substances can take many forms including:

Control is important, as some substances do not have immediate affects e.g. symptoms of exposure to silica may not occur until twenty to fifty years after exposure.

COSHH sets out, in broad and general terms, the measures needed to prevent or adequately control exposure to hazardous substances in virtually every place of work. The definition of hazardous substances includes:

To make it easier any substance displaying one of the following symbols will require an assessment:

You may find the older orange and black warning symbols are still used on some substances (these will be phased out by 2015). Examples of this older style symbol can be seen below:

(These symbols are only relevant to specific substances for example adhesives, further advice is required for substances generated during a work process, naturally occurring substances and biological agents).


The COSHH regulations require you the employer (including the self-employed) to carry out an assessment of the substances used. There are 8 steps that need to be followed:

Step one

Assess the risk to health from the substances either being used or created.

The assessment must take into account:

Unless quantities of hazardous substances used are deemed to be so low that there is only a slight risk to the health of employees, the employer must ensure that they have arrangements in place to deal with accidents, incidents and emergencies.

This may include the provision of additional first aid facilities and safety drills.

The information concerning these arrangements must be readily available and displayed if necessary, together with the provision of suitable warning and communication systems.

Should an incident then occur, the employer must then take immediate steps to restore the situation to normal and control the effects that led to the incident.

Step two

Decide what precautions are needed – You must not allow work to be carried out where hazardous substances are involved, without considering the risks and putting precautionary measures in place to protect employees and others who may be effected by the work.

Step three

Prevent or adequately control exposure- There is a hierarchy of control measures that should be applied to hazardous substances, which is shown below in descending order of priority:

Step four

Ensure the control measures are maintained and used properly and that the safety procedures are followed.

All control measures have to be maintained to ensure that they are still effective. If not otherwise specified, the measures taken should include visual checks and examinations as prescribed by the manufacturer.

There is a legal requirement to ensure that all LEV plant is thoroughly examined and tested at least once in every 14 months. There is also a requirement to ensure that RPE is thoroughly examined at least once a month, this requirement does not apply to single use disposable respirators.

Step five

Monitor exposures.

Measure the concentration of hazardous substances in the air breathed in by workers where your assessment concludes that:

Workplace exposure limits are levels above which there is a known risk to health – these must never be exceeded.

N.B. There is no absolute “safe” level of exposure for dangerous substances, and employers should aim to bring exposure to the lowest achievable level.

Step six

Carry out appropriate health surveillance, if applicable.

For certain hazardous substances there is a requirement to carry out health surveillance.

These substances are listed in the Regulations.

Health Surveillance may also be necessary in situations where early detection will be beneficial in arresting the progression of ill health. Refer to Guidance Note 18 – Health Surveillance for further information on this topic.

Step seven

Prepare plans and procedures to deal with accidents, incidents and emergencies.

Where the work activity may lead to risk of an accident, incident or emergency involving exposure to a hazardous substance, which goes well beyond the risks associated with normal day-to-day work, you should set up warning and communication systems to allow a suitable response immediately should any incident occur. This is to ensure information on your emergency arrangements is available to those who need to see it, including the emergency services. It also requires these ‘safety drills’ to be practiced at regular intervals.

Only those staff necessary to deal with the incident may remain in the area and they must be provided with appropriate safety equipment.

Do not produce emergency procedures if:

BUT, the requirements described in Step seven must be complied with in full where carcinogens, mutagens or biological agents are used.

Step eight

Ensure employees are properly informed, trained and supervised.

Where to get information on hazardous substances.

Information on hazards posed by chemicals can be found through various sources:

Asbestos and Lead

Asbestos and Lead are subject to their own regulations and are not covered by COSHH:


Further guidance