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Report on HSE consequences of working hours schemes and shift work

What do we know about the consequences for HSE of working hours schemes and shift work in the petroleum activities? And what do we know that we know too little about? A new report sums up what we do know and indicates areas where more research is needed.


On assignment from the Ministry of Labour and Social Inclusion, the Petroleum Safety Authority Norway (PSA) has surveyed what is known in this field and identified areas where more research is needed with regard to the HSE consequences of working hours schemes and shift work in the petroleum activities. The project was carried out in close cooperation with employer and employee unions, the Directorate of Labour Inspection (DLI) and international research institutions.

The final project report sums up what is known at present and draws attention to areas where further research is needed.

Health and accident risk
Data from a great number of other industries, from the British shelf and other community sectors, show that night work entails a considerable higher accident risk than daytime work. The transition between night and day leads to sleep complaints and diurnal rhythm disturbances that affect alertness and mental performance.

  • Experimental studies show that both night work and long periods without sleep can reduce one's perception of a situation and reaction time as much as a blood alcohol content between 0.05 and 0.1 per cent.
  • Data from other industries show a clear connection between night/shift work and several serious illnesses. For instance, night work increases the risk of cardiovascular disease by 30 - 60 per cent, compared with daytime work. The risk of breast cancer increases similarly.
  • There is also a strong synergy effect between shift work and lifestyle factors such as smoking, overweight, lack of physical activity and serious diseases. This means, for instance, that the risk of coronary heart disease for a daytime worker who smokes, is approximately 50-60 per cent higher than for a non-smoker, while smoking combined with shift work gives an increase of nearly 100 percent compared to a non-smoker. Studies have also shown that shift workers in general have a less healthy lifestyle than others.

There is a great need to initiate studies looking at to what extent these findings are relevant for the Norwegian petroleum industry.

Agreeing to disagree
The employer/employee parties and the authorities agree that the reports describe our present knowledge and its shortcomings in a satisfactory and balanced manner.

However, there is not complete agreement as to how far results from experimental studies, studies conducted on the continental shelves of other nations and in other industries can be transferred to the working hours schemes and framework conditions that apply in our offshore petroleum industry and in construction projects onshore. One of the project recommendations is to verify to what extent research conclusions related to safety are transferable to the Norwegian petroleum activity.

The report points out the need for research on individual and organisational factors in connection with working hours schemes that may have an effect on the following key areas:

I. Safety and factors that affect the risk of accidents (alertness, performance, risk perception, risky behaviour, etc).
Examples of such factors are long working days, long weeks and night work, interaction with other working environment factors plus framework conditions and measures which fully or partly compensate for working hours factors.

II. Health and reduced work capacity (health complaints, disease, rejection, retirement, etc).
In this area, it will be necessary to monitor employees over a period of time, since changes in health and work capacity develop over a long time. Here, too, it is important to look at the interaction between working hours and other factors in one's working environment and spare time, individual matters such as age, lifestyle and social conditions. More knowledge is also needed on framework conditions and measures that may help remove or reduce negative health effects.

Report in three parts
The final report consists of three parts. Part 1 is in Norwegian only and includes recommendations on knowledge and research needed which are supported by the employer and employee unions in the industry, as well as the DLI, STAMI (National Institute of Occupational Health) and the PSA.

Some of the parties and the DLI have also expressed a wish for knowledge related to various specific areas not covered by the overall recommendations, although this does not necessarily imply contradictory research needs. From the PSA's point of view, the knowledge deficiencies and research needs are greatest when it comes to the long-term effects on health and work capacity of the working hours schemes in the petroleum activities.

Parts 2 and 3 are reports from research institutions in Finland and Great Britain. They sum up knowledge status and pinpoint areas where there is deficient knowledge.

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