Health and Safety
Executive / Commission
Human factors
More than 3.5 million people are employed as shift workers in the UK. They work in a wide variety of industries including the emergency services, healthcare, the utilities, transport, manufacturing (including oil, gas & chemical industries), entertainment and retail. Poorly designed shift-working arrangements and long working hours that do not balance the demands of work with time for rest and recovery can result in fatigue, accidents, injuries and ill health.
Research has shown that there can be undesirable consequences for those working shifts, particularly night and early morning shifts. These include disruption of the internal body clock, sleeping difficulties and fatigue, which in turn can affect performance, increase the likelihood of errors and accidents at work and may affect health and well-being in the long-term.
Sleep disturbances can lead to a ‘sleep debt’ and fatigue. Night workers are particularly at risk of fatigue because their day sleep is often lighter, shorter and more easily disturbed because of daytime noise and a natural reluctance to sleep during daylight.
Fatigue is generally considered to be a decline in mental and/or physical performance that results from prolonged exertion, sleep loss and/or disruption of the internal clock. It is also related to workload, in that workers are more easily fatigued if their work is machine-paced, complex or monotonous.
If workers are fatigued, they will be less alert, their reaction time will be slower, they will find it less easy to concentrate and may make ill-judged decisions. As a result they may make more errors, which can lead to accidents and injuries.
It is important not to underestimate the risks of fatigue. For example, the incidence of accidents and injuries has been found to be higher on night shifts, after a succession of shifts, when shifts are long and when there are inadequate breaks. Fatigue has also been implicated in 20 % of accidents on major roads. It has been identified as a contributory factor in many major incidents including Challenger, Chernobyl, Clapham Junction and Exxon Valdez and is said to cost the UK £115 - £240 million per year in terms of work accidents alone.
Reducing the risks associated with shift work and fatigue can improve the health and safety of workers and may also financially benefit business and society in general by reducing sickness, injuries and accidents, and by increasing work efficiency and product quality.
In the UK, there is no specific health & safety legislation on shift working. Nevertheless employers have general health & safety responsibilities (e.g. a duty of care in law) for their employees (and others) . This duty includes removing or controlling the risks of fatigue by properly organising and planning shift-working arrangements. Their broader responsibility for the health and safety of others (e.g. the public) that might be affected by their work activities provides another reason why it is important to control fatigue.
The Working Time Regulations are also relevant to the planning and organisation of shifts, especially night shifts. Some workers in certain sectors such as the railway and aviation industries and mobile workers in road and sea transport may also be subject to industry-specific legislation, which lay down specific requirements in relation to the organisation of working time.
There are many different shift work-schedules and each schedule has different features. This sheer diversity of work and workplaces means that there is no single optimal shift system that suits everyone. However, a planned and systematic approach to assessing and managing the risks of shift work can improve the health and safety of workers.
There are a number of key risk factors in shift schedule design, which must be considered when assessing and managing the risks of shift work. These are the workload, the work activity, shift timing and duration, direction of rotation and the number and length of breaks during and between shifts. Other features of the workplace environment such as the physical environment, management issues and employee welfare can also contribute to the risks associated with shift work.
All the key risk factors are covered in detail in Managing Shift Work: Health and Safety Guidance , which provides practical advice on how to reduce the risks associated with them. This advice is also summarised in the form of good practice guidelines.
HSE’s new book, Managing shift work: health and safety guidance is particularly useful for employers, safety representatives, trade union officials, employees, regulators and other stakeholders. By drawing together advice and best practice from a range of sources, the guide explains employer’s legal duties, the key risk factors and describes the impact shift work can have on health and safety. It also offers sensible advice on controlling, managing and monitoring the risks of shift work.
Copies of Managing shift work: health and safety guidance, (HSG 256) ISBN 0 7176 6197 0, priced £9.95 are available from HSE books and other good booksellers.
HSE has also developed the Fatigue and risk index , a free assessment tool, which can be used to compare alternative patterns and help identify whether any particular aspects of an existing or proposed working time pattern are likely to increase the risk of fatigue.