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Safety around the clock

Photo of offshore worker Photo: Anne Lise Norheim
Photo of offshore worker Photo: Anne Lise Norheim
Lengthy working days and night shifts are essential in many occupations if society is to function.
But how do long hours, overtime and shift work affect people – and what do they mean for risk management?
  • Working environment

The Norwegian Ocean Industry Authority (Havtil) has seen a worrying trend towards extended working hours in the petroleum industry.

Its audits show that regulations in this area are being breached and that too little is being done to assess the negative consequences related to widespread use of overtime and extended offshore tours.

“We see that working hours are not given adequate consideration as a risk factor,” says principal engineer Elisabeth Lootz in Havtil’s occupational health and safety discipline.

“What does it mean, for instance, if somebody works more than 12 hours at a stretch? How do the companies ensure that they have control of exposure when limit values for noise and chemicals are specified in terms of 12-hour shifts?

“What impact do long working days have on the ability to maintain good situational awareness and to respond rapidly when incidents occur? What does working time mean for the risk of errors and the health of individuals?”

Expertise lacking

Lootz believes that the companies do not pay sufficient attention to the negative consequences of overtime working. She wants specialists with expertise about the psychosocial and organisational working environment, and about human factors, to be more involved in assessing the risk and proposing measures.

“The people responsible for planning work offshore often know too little about the working time regulations,” she notes.

It is particularly worrying that Havtil’s audits repeatedly identify the same problems in the same companies.

“This shows that management of working time is weak in some companies, and that a better grasp is needed of the risks involved in increasing the hours worked,” Lootz emphasises.

Working time, shift work and risk

Elisabeth Goffeng, who studies shift working at Norway’s National Institute for Occupational Health (Stami), notes that night work enhances the risk of fatigue and error in the short term and poses health problems in a longer perspective.

“If you’ve been awake too long, you can be overwhelmed by sleep and have ‘microsleep’ episodes,” she explains. “These typically occur late in a night shift, and can last from one second to a whole minute – and you don’t always even notice the loss of consciousness.”

Both Goffeng and Lootz spoke on these issues at a Havtil seminar on human opportunities and limitations on 26 September 2023. Go here to see their presentations, in Norwegian only.

Long days hit health

Studies show that tiredness accumulated over time through long working days can have a debilitating effect on the body and increase the risk of cardiovascular disease.

Recent research has also found a small correlation between excessive work periods and depression, and an increased risk of breast cancer among personnel working for many nights in a row over several years.

Goffeng believes that these findings justify caution over doing long periods of work at night. She notes that breaks appear to have a protective effect, and that it is important the employer makes provision for adequate rest between lengthy sessions of such shifts.

“Although the correlations are moderate or weak, employers should perform detailed assessments, in cooperation with employees, of the acceptability of long working days.

“They should look at the length of the work day, breaks, positioning of working shifts in the day and whether the arrangements contribute to sleep deficits.

“This isn’t about eliminating all shift work, but involves finding good solutions which limit its negative consequences as much as possible.”


However, shift working and long days are not the only factors affecting the attention people pay to their job. Another is how demanding their tasks are.

Goffeng points to studies conducted with airline pilots working long days in succession. These show that their reaction time increases significantly for each take-off and landing.

“The risk of making errors rises with the workload, not just the number of hours worked,” she says. “So it’s also important to look at the total burden imposed by shift arrangements, and tailor measures to the work to be done.”

Stami advice on working time in relation to health and safety

  • Rotate shifts clockwise
  • Preferably begin shifts before 07.00 in the morning if the nature of the work makes this possible (must be agreed)
  • Avoid as far as possible working more than 10 hours per day
  • Avoid as far as possible working more than 48 hours per week
  • A minimum of 11 hours of rest between shifts
  • Make provision for a break of at least 30 minutes every fourth hour
  • Make provision for power naps at work if the nature of the job makes that possible (must be agreed)
  • Involve the employees in planning tours of duty
  • Adapt shift work to employee age – the burden rises with the years

Source: Stami - Råd om arbeidstid med hensyn til helse og sikkerhet (in Norwegian only)