A Guide to implementing COSHH Legislation in the workplace

 Every year exposure to hazardous substances at work affects the health of many thousands of people. Common examples include:

  • lung disease (e.g. airborne particulate matter / dusty conditions), 
  • skin irritation, dermatitis or skin cancer (e.g. from frequent contact with oils, or contact with corrosive liquids / risk phrase substances from surface cleaning, coating or manufacturing processes etc.),
  • occupational asthma (e.g. sensitisation to isocyanides in paints or adhesives),
  • toxic fumes, occupational cancer etc. 


The COSHH Regulations 2002

These provide a framework to help protect people in the workplace against health risks from hazardous substances. The substances may be used directly in the work (e.g. cleaning chemicals, chemical reagents) or may arise from the work (e.g. dusts, fumes and waste products).

COSHH lays down a sensible step-by-step approach to the necessary precautions and is therefore a useful tool of good management. The potential for identifiable cost benefits (e.g. tighter control over the use and storage of materials), improved morale and industrial relations have been widely realised.

COSHH applies to virtually all substances hazardous to health. Exceptions include asbestos and lead and substances which are hazardous only because they are radioactive, asphyxiants, are stored at high pressure/temperature or have explosive/flammable properties most of which are covered by separate regulations.

Definitions, Hazard & Risk

  • Hazard - is the potential to cause harm
  • Risk - is the likelihood that it will harm you in the actual circumstances of use

The risk will depend on a number of factors, such as the hazard presented by the substance, how it is used, how exposure is controlled, the degree and extent of exposure etc.

COSHH requires the following:

Assessment of the risks

Deciding what precautions are needed

Prevention or control of the risks

Ensuring that control measures are used and maintained Monitoring exposure and health surveillance, where necessary

Informing, instructing and training employees about the risks and precautions needed.

Assessment - a step-by-step approach:

Identify what hazards there are

Evaluate the risks to people

For significant risks, decide on the action needed to remove or reduce them to insignificant levels.

Assessment is the responsibility of the employer. Persons preparing the assessment will need to: 

have access to, and understand, COSHH, related legislation, codes of practice and published guidance

be competent to carry through the work of assessment 

consult widely within the workforce and inform them of results accordingly consider peripatetic workers (who work for you on other premises)

Hazards - Substances hazardous to health include:

Substances classified as dangerous to health under the Chemicals Hazard Information and Packing for Supply (CHIP3) Regulations 2002. Many are listed in "The Approved Supply List" which is part of the "CHIP 3" regulations.

Substances with occupational exposure limits (these are specified in Guidance Note EH40 which is revised annually)

Biological agents

Dusts of any kind in substantial concentrations

Identification of hazardous substances can be sought from:

Hazard data sheets, labels etc. from suppliers (required by law) from which you must draw conclusions relevant to the way the substance is used in the workplace Knowledge from within your business or industry; trade literature, published guidance/documents

Part V of the Approved Supply List (Health & Safety Executive)

Risks - Risk assessment involves looking at:

Use, handling, generation, release etc. of hazardous substances Who might be affected and likely exposure level/extent

Nature of exposure (breathing in, swallowing, skin absorption etc.)

Current measures to prevent or control exposure - effectiveness and use

Accidental leakage, spillage or release

Cleaning and maintenance operations

Further Action following results of Assessment

No likelihood or insignificant risk - no further action until review of assessment.

Risks identified - ensure appropriate control measures, in the following order of priority:-

  1. Prevention
  • change process/activity so that the hazardous substance is not required or generated
  • replace with safer alternative (see HS(G)110 in Ref/Further Details section) substitution
  • use it in safer form
  1. Control may include any of the following:- 
  • total enclosure of the process
  • partial enclosure and extraction equipment
  • general ventilation 
  • using systems of work and handling procedures which minimise chances of spills, leaks etc. or exposure to the substance(s)
  1. Personal protective equipment (eg respirators, protective clothing) only as a last resort when you cannot adequately control exposure by any combination of the measures above.

Employees are required to make proper use of control measures and to report defects.

Employers are required to keep controls in efficient working order and good repair. Engineering controls and respiratory protective equipment have to be examined and, where appropriate, tested at suitable intervals. Suitable records of all such actions taken must be kept.

Monitoring exposure is required in certain circumstances, e.g. where there could be serious risks to health if control measures were to fail or deteriorate or where you cannot be sure that exposure limits are not being exceeded. Records of monitoring should be kept.

  1. Health surveillance is required
  • where an employee is engaged in one of the processes listed in Schedule 5 of COSHH and is likely to receive significant exposure to the substance involved.
  • where employees are exposed to a substance linked to a particular disease or adverse health effect and there is reasonable likelihood under the conditions of the work of that disease or adverse health effect occurring and it is possible to detect the disease or adverse health effect. Suitable records must be kept for 40 years.

Informing, Instructing and Training Employees

Appropriate training & briefing sessions must be carried out by employers regarding the substances and their associated risks and precautions. Sufficient information and instruction should be given on control measures, personal protective equipment, results of any exposure monitoring or health surveillance and emergency procedures.

Recording and Reviewing the Assessment

Unless the assessment is so simple that it can be easily recalled and its conclusions explained, it should be put in writing. Reviews should take place regularly, at not less than five-yearly intervals, and in any case where it is no longer valid or there have been significant changes in the work.

References/Further Details

Booklet L5-General COSSH ACOP, Carcinogens ACOP and Biological Agents ACOP(HSE) ISBN 0 7176 1670

A step by step guide to COSHH assessment - HS(G) 97 (HSE) ISBN 0 7176 1446

COSHH - a brief guide for employers IND(G) 136L (HSE). www.hse.gov.uk/pubns/indg136.pdf

Steps to successful substitution of hazardous substances HS(G) 110 (HSE) ISBN 0 7176 0695 3.

Health surveillance under COSHH (HSE) ISBN 9 780118 854474

Booklet HS(G)54: Maintenance, examination and testing of local exhaust ventilation (HSE). ISBN 0-7176-1485-9

Booklet HSG187: Control of Diesel Engine Exhaust Emissions in the Workplace. (HSE) ISBN 0 7176 1662 2