Occupational Health

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What is occupational hygiene?

Occupational hygiene is a field of health and safety involved in protecting workers  health from workplace hazards that may cause harm. The five principles of occupational hygiene are:

  1. Anticipate the hazard(s)
  2. Recognise the hazard(s)
  3. Evaluate the hazard(s)
  4. Control the risk caused by the hazard(s)
  5. Confirm controls are effective

Through science and engineering, occupational hygienists identify, evaluate and control exposure to workplace health hazards that come in many different forms, for example; chemicals, dusts, fumes, noise, vibration etc.

The role of an Occupational Hygienist is to understand workplace health risks and communicate advice on what needs to be done to prevent serious illnesses like occupational cancer, occupational asthma, occupational skin diseases, noise induced hearing loss etc.

As part of the identification and evaluation of health hazards an occupational hygienist may need to measure and monitor the exposure of the worker (to dust, fume, noise, chemicals, vibration etc.) in order to assess the level of risk. The output from measurements and monitoring surveys should be in the form of an occupational hygiene report.

Do I Need an Occupational Hygienist?

Often the risks from health hazards present in the workplace is not readily apparent, recognised or understood. They can cause serious ill-health over time from acute (short term), chronic (long term) exposures or repeated low level exposures if the hazard has not been identified and appropriate controls applied.

Important health and safety legislation includes:

  • Control Of Substances Hazardous to Health Regulations (Northern Ireland) 2003
  • Control of Noise at Work Regulations (Northern Ireland) 2006
  • Control of Vibration at Work Regulations (Northern Ireland) 2005
  • Control of Lead at Work Regulations (Northern Ireland) 2003
  • Control of Asbestos Regulations (Northern Ireland) 2012

These regulations require employee exposure to certain hazards to be monitored in order to effectively assess the level of risk to their health, to provide assurance that the employer is not exceeding occupational exposure limits (EH40/2005 Workplace Exposure Limits) set out in the regulations and that current control measures are effective in protecting employees health.

Examples of when you may need an occupational hygienist are when:

  • you need competent assistance and advice to identify the most suitable control solution for a particular scenario
  • failure or deterioration of the control measures (e.g. a lack of containment, or LEV not performing as intended) could result in a serious health effect
  • you need exposure monitoring to be sure that an occupational exposure limit (e.g. WEL) or any self-imposed (in-house) exposure standard is not exceeded and to ensure that control measures are effective
  • use of a specific substance and processes for which monitoring is required; listed in Schedule 5 of COSHH Regulations
  • youv require a general review of existing arrangements for the management of health hazards

How Do I Find an Occupational Hygienist?

It is the employers responsibility under Health and Safety legislation to ensure they appoint a competent person to carry out any occupational hygiene services. 

Deciding exactly what help you need is very important as this will help you identify what type of specialist is best placed to assist you.

The British Occupational Hygiene Society is the UK professional body for Occupational Hygienists and has a ‘Buyers Guide for Obtaining Occupational Hygiene Services’ - BOHS-Buyers Guide - September 2021. There is also a Directory of Occupational Hygiene Services - Directory of OH Services (bohs.org)

When selecting an occupational hygiene service provider, there are some key considerations:

  • do they have evidence of relevant competency, such as formal qualifications and training (e.g. the BOHS Certificate of Operational Competence or the Diploma of Professional Competence)?
  • do they have practical experience related to your industry, or processes?
  • can they explain to you why they are competent to advise you on this problem?
  • do they have the resources to complete the work within the required timescale?
  • can they provide references for completed work on similar projects?
  • are they a member of a relevant professional body e.g. BOHS (British Occupational Hygiene Society), FAAM (Faculty of Asbestos Assessment and Management), IOA (Institute of Acoustics), ILEVE (Institute of Local Exhaust Ventilation Engineers), IOSH (Institute of Occupational Safety and Health), or similar?

Anyone who provides an occupational hygiene service must be competent to do so and be able to demonstrate that they have appropriate training and experience in the service to be provided, e.g. exposure monitoring, assessment of LEV etc.

They should be familiar with the relevant monitoring standards and methods published by HSE and professional bodies, have adequate knowledge of occupational exposure limits and monitoring strategies, demonstrate adequate continuing professional development, and be committed to providing sensible and proportionate advice.

A competent person should be able to apply a monitoring strategy suitable for the actual circumstances found in the workplace. This requires a good knowledge and understanding of the particular industry and process. It should include discussion and input of knowledge and experience from both the management and workers at that workplace.

Have I received the help I needed?

Advice given must be based on a correct assessment of the risk and take account of established standards, such as the principles of good control practice and occupational exposure limits. The output from the service provider should provide you with a practical, sensible solution to your problem. 

As an employer you should read the report and if you think it is incorrect or you do not understand or agree with any part of it, you should discuss with the consultant accordingly.

The report provided should be clear, concise and adequate, and accurately reflect your working practices. It should be suitable and contain detailed information to allow employers, employees, safety representatives and enforcing authorities to understand and draw conclusions about the processes, work activity and the effectiveness of exposure control.

The regulations referred to previously and their associated Approved Codes of Practice (ACOP) stipulate what details should be contained in an exposure monitoring record. BOHS also have a guidance on occupational hygiene reports which can be found in the link below:

How to write an Occupational Hygiene Survey Report

An Occupational Hygiene report should provide clear, concise, informative and verifiable information. This will allow employers, employees, safety representatives and enforcing authorities to understand and draw conclusions about the processes, work activity and the effectiveness of exposure control.

To find out how to write an Occupational Hygiene Survey Report, please see the following link:










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How to request information from the Health and Safety Executive Northern Ireland including Freedom of Information (FOI) and the use of our Publication Scheme.