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Appreciation of factors affecting health and safety at work (including the control of substances hazardous to health)

Appreciation of factors affecting health and safety at work (including the control of substances hazardous to health)



The workplace has an important bearing on health because of the multitude of hazards which exist in many working environments.  Those hazards may relate to a wide range of physical, chemical and biological agents.  Many aspects are regulated (e.g. the Health and Safety at Work Act[1], and the Control of Substances Hazardous to Health regulations[2]), while in other areas guidance and approved Codes of Practice help to maintain good working practices (e.g. EU Working Time Directive[3]).  Positive aspects of the occupational environment for health are briefly considered in the next section (9).


Key definitions and terms

Health and safety

Preventing people from being harmed or becoming ill by work by taking the right precautions; providing a satisfactory working environment


Anything that may cause harm e.g. chemicals, electricity, working from ladders, an open drawer

Risk assessment (for health and safety)

A careful examination of the potential causes of harm in the workplace, so as to inform the implementation of reasonable measures to reduce health risks


The adverse reaction people have to excessive pressure or other types of demand placed on them


Workplace health, safety and welfare

The workplace

The workplace is an environment in which most adults spend a substantial fraction of their time. It has the potential to have both positive and negative influences on their health and well-being – sometimes with lasting effects.  Factors influencing health include the following:

Workplace factors affecting health

  • Temperature and humidity.
    - Adequate (indoor) heating is important to provide thermal comfort in cold weather (normally to at least 16 °C if work is mainly sedentary, and to at least 13°C where physical effort required).  Particular cold stresses may occur in certain occupations, e.g. food preparation, open air working;
    - Protection is also needed against heat stress from high ambient temperatures, high thermal radiation and/or high levels of humidity (laundries, foundries etc).
  • Ventilation.
    - Adequate air movement and rate of air exchange is important to maintain air quality;
    (NB From 1 July 2007, it has been against the law to smoke in enclosed public places and workplaces in England. Similar legislation exists in Scotland and Wales. Most countries have some enforcement of bans on smoking[4]).
  • Ergonomics / physical arrangement of work area & equipment.
    - These are factors that allow people to work comfortably and in safety.  For example, for office workers, the height and orientation of computer screens, chairs which provide postural support.
  • Space, lighting and cleanliness of the work area.

Safety factors

  • Maintenance/good repair.
    - Especially important for safety equipment and equipment which could create a risk if faulty
  • Routes for safe movement of people and vehicular traffic, including provision of unobstructed emergency exits
  • Physical aspects.
    - Doors, gates, windows should be suitably constructed and fitted with safety devices if necessary (e.g. to prevent risk of fall if above ground level, shatterproof glazing in doors etc).  Use of such measures as fencing, rails and covering of pits/tanks to prevent risk of falls from height.
  • Control of hazardous agents (see below).


Facilities for the welfare of workers and visitors include:

  • lavatories and washing facilities;
  • provision of drinking water;
  • facilities for rest and to eat meals.

Specific hazards

Many work environments contain sources of hazardous substances (chemicals, dust, fumes, biological agents), which may cause exposure by inhalation, dermal absorption, splashing into eyes, or ingestion.  These are covered by specific legislation (see COSHH below).

One of the most common forms of workplace injury arises from slips and trips.  Care to remove tripping hazards is especially important where there is public access.  Falls from height, especially off ladders, is one of the major contributors to workplace deaths and serious injuries.

Musculoskeletal disorders relating to workplace activities are common, and include injuries from manual handling (heavy lifting etc – a major cause of days off work) and repetitive strain injuries (RSI). Display screen equipment (e.g. computer) can give rise to musculoskeletal disorders, including RSI, and eye strain.

Asbestos is the largest single cause of work related fatal disease and ill health in Great Britain, though it is now mostly the result of past exposures.

Powered hand tools etc can cause ‘vibration syndromes’, and vibration from a machine or passing through the seat of a vehicle can cause or aggravate whole back pain.  Noise can damage hearing, but it can also be a serious nuisance affecting concentration and physiological parameters.

Most electricity deaths are caused by contact with overhead or underground power cables.  Non-fatal shocks can cause severe and permanent injury.

Pressure systems – systems containing a fluid under pressure (e.g. pressure cookers, boilers, steam heating systems) – account for about 150 incidents / year in England, mainly due to equipment failure through poor design, incorrect operation or poor maintenance.

Radiation risks are usually strictly controlled.  Ionising radiation risks may arise from exposure to x-rays or radionuclides e.g. medical imaging, as well as from radon gas from the ground.  This also includes damage and cancer risk from UV radiation (e.g. from sun).


Stress is an over-used and imprecisely defined term. However, it is clear what most people mean by it, and there is a large body of research that shows a link between markers of stress and subsequent ill health.  The UK Health and Safety Executive defines stress as ‘the adverse reaction people have to excessive pressure or other types of demand placed on them.’[5]  It can be tackled in similar way to any other form of workplace hazard – by identifying contributing causes and attempting to reduce them. Factors that often appear important include:

  • lack of control over the way work is done;
  • work overload (or underload);
  • lack of support from managers;
  • conflicting or ambiguous roles;
  • poor relationships with colleagues (including bullying);
  • poor management of organisational change.


Responsibilities and the law


In England, health and safety within factories, farms and building sites is enforced by the Health and Safety Executive (HSE)[6], and in offices, shops, hotels, and catering and leisure facilities by Environmental Health in local authorities[7].


Three main forms of regulation are used:

  • Guidance (not compulsory, but aimed at helping compliance with the law);
  • Approved Codes of Practice (support good practice, and have legal status in that an employer may be found at fault if they have not followed relevant provisions);
  • Regulations (legal requirements).


In recent years, more health and safety law has originated from Europe as proposals and Directives of the European Commission, but the main basis of British legislation is:

- Health and Safety at Work Act 1974[8], which sets out the general duties which employers have towards employees and members of the public, and employees have to themselves and to each other ‘so far as is reasonably practicable’

- The Management of Health and Safety at Work Regulations 1999[9] (the Management Regulations), which make more explicit what is required of employers under the Health and Safety at Work Act

Employers have responsibility to ensure the health, safety and welfare of their workforce (with a written policy if they have more than five employees), to assess risks, to ensure implementation of necessary protection measures, to provide relevant staff training, to publicise health and safety information, to report injuries and accidents.

Employees have a duty to take reasonable care for their own health and safety and that of others, to cooperate with an employer on health and safety matters, including by use of protection equipment.  Employees can refuse to do something unsafe without being threatened with disciplinary action.


Risk assessment

Risk assessment

Much of health and safety is based on the principle of risk assessment (note, the use of the term risk assessment here should be distinguished from its use to imply quantification of risk (similar to health impact assessment) as described in section 10 below).

The law does not expect elimination of risk, but it requires that people are protected as far as ‘reasonably practicable’.  The principal elements of a risk assessment are:

(1) To identify the hazards;
(2) To decide who might be harmed and how;
(3) To evaluate the risks and decide on precautions;
(4) To record and implement findings;
(5) To review risk assessment and update if necessary.


Control of Substances Hazardous to Health (COSHH)


The law requires employers to control exposure to hazardous substances – chemicals, dusts and fumes – that may cause toxic effects, infections, cancers, allergic responses, asphyxiation etc.  The principal law is the Control of Substances Hazardous to Health Regulations 2002 (COSHH) (as amended)[10]

These regulations cover substances that are dangerous to health, including biological agents, substances with workplace exposure limits, pesticides, medicines, cosmetics and substances produced in chemical processes.  Asbestos, lead, radioactive materials, and substances with explosive or flammable properties are covered by other regulations.

COSHH sets out eight steps that employers (and sometimes employees) must take.  They are:

  • Assess the risks;
  • Decide on necessary precautions;
  • Prevent or adequately control exposure;
  • Ensure use and maintenance of control measures;
  • Monitor exposure;
  • Carry out appropriate health surveillance;
  • Prepare plans and procedures for accidents, incidents and emergencies;
  • Ensure employees are properly informed, trained and supervised.
  • The EU ‘Registration, Evaluation, Authorisation & restriction of Chemicals’ (REACH) Regulation places responsibility on industry to manage the risks from chemicals and to provide safety information on the substances available on the market.[11]


Key references


Useful websites



                                    © Dr Paul Wilkinson 2009, Helen Crabbe and Rebecca Close 2016