Before considering checks and interventions for health effects on workers, the range of possible effects needs to be considered, alongside injuries caused by safety issues. There are often links between the health and safety aspects of work. A health effect can have an influence on the chances of an accident, for instance through physical weaknesses brought on by exposure to hazardous substances, or fatigue. Conversely a safety concern can have a longer-term effect on health, such as poor conditions in the workplace or unsuitable equipment.
The key factors in whether something causes harm to health are:
- the duration of exposure
- the level of exposure
- the mode of exposure, eg, contact, inhalation, injection or ingestion
- in the case of chemicals
- individual susceptibility and behaviours, eg, young or old workers, those with disabilities
- the work environment – does the layout make the activity more hazardous, eg, incorrect height, poor ventilation or lighting?
- variables such as different work rates, and seasonal variations, eg, wind, rain and sunlight.
Effects on health, and their causes, can be divided into acute and chronic, as follows.
Acute causes and effects (immediate factors)
- are instantaneous or develop a few seconds to hours after exposure
- usually have an easily identifiable source (cause)
- can follow repeated or prolonged exposure, eg a worker developing contact dermatitis from oil
- can be recovered from (or the condition is managed), with treatment or by preventing further exposure
Chronic causes and effects (delayed)
- occur gradually over a long period (years)
- produce no obvious signs of ill health at the time of exposure
- are diagnosed by medical professionals
- are not easily linked to a specific health hazard, exposure or work activity/workplace
- often have no cure, but treatment may alleviate symptoms, eg, cancer or chronic obstructive pulmonary disease.
The main range of health effects to which workers could be exposed include:
This includes noise, vibration, heat (and lack of it), light levels, radiation and compressed air. Ergonomic risks will be dealt with in a separate section. The effects of exposure to high noise levels include hearing loss and tinnitus. Excessive or prolonged exposure to vibration can cause conditions such as vibration white finger and Raynaud’s syndrome. Excessive heat levels can result in heat exhaustion and dehydration. Exposure to radiation can cause cancers (not forgetting skin effects such as melanoma from exposure to the sun). Compressed air can cause blast or injection injuries.
Workers could be exposed to toxic, irritant, oxidising, mutagenic or flammable chemicals, or dusts. This category includes occupational cancers arising from exposure to asbestos, carcinogenic solvents or welding fumes; respiratory diseases such as silicosis and asthma; skin diseases such as dermatitis; and infertility or miscarriages due to exposure to chemicals or biological agents.
Here, the distinction is between naturally occurring biological risks (eg, infections from animals and plants, viruses) and biological risks created by humans (eg, manufactured pathogens, pharmaceuticals). Also included would be communicable and non-communicable diseases, the former including infectious diseases such as HIV and hepatitis.
This category would include mental health issues such as depression and anxiety, and psychological effects of work and workplace culture, such as lack of control over work and stress. This also covers lone working, night working, shift working, violence, aggression and bullying.
Ergonomics can be considered the study of human–machine interfaces, and matching work equipment to the dimensions and abilities of workers. This includes the design of items such as control panels to ensure optimum operation by workers, design of workstations to minimise awkward or repetitive movements or poor postures being adopted, and arguably the use of display screen equipment. Manual handling could also be included in this category of risks. The effects of poor ergonomics and manual handling include chronic back pain, upper limb disorders affecting the arms and hands, and strains and sprains.
A summary of the main types of health hazard are given below: