Extended/Unusual Work Shifts Guide


The Occupational Safety and Health Act (OSH Act) requires employers to comply with hazard-specific safety and health standards. In addition, pursuant to Section 5(a)(1) of the OSH Act, employers must provide their employees with a workplace free from recognized hazards likely to cause death or serious physical harm. Emergency Preparedness Guides do not and cannot enlarge or diminish an employer's obligations under the OSH Act.

Emergency Preparedness Guides are based on presently available information, as well as current occupational safety and health provisions and standards. The procedures and practices discussed in Emergency Preparedness Guides may need to be modified when additional, relevant information becomes available or when OSH Act standards are promulgated or modified.

What is an Extended/Unusual Shift and when are they used?

A normal work shift is generally considered to be a work period of no more than eight consecutive hours during the day, five days a week with at least an eight-hour rest. Any shift that incorporates more continuous hours, requires more consecutive days of work, or requires work during the evening should be considered extended or unusual. Extended shifts may be used to maximize scarce resources. Long or unusual shifts are often required during response and recovery phases of emergency situations such as terrorist threats, which generally come without warning, require continuous monitoring, and may overwhelm local responders both technically and tactically. These schedules ensure that the appropriate scarce resources are in place and accessible while full mobilization is being developed.

Is there an OSHA standard covering this?

Currently, there is not a specific OSHA Standard for extended or unusual work shifts. This document is intended solely as a guide to provide information to employers and workers.

What should workers know?

Extended or unusual work shifts may be more stressful physically, mentally, and emotionally. Non-traditional shifts and extended work hours may disrupt the body's regular schedule, leading to increased fatigue, stress, and lack of concentration. These effects lead to an increased risk of operator error, injuries and/or accidents.

Society is oriented toward traditional daytime work hours and work at night will often intensify fatigue and reduce alertness. Workers generally will not acclimate to night work, and sleep patterns will generally be disrupted so the non-work periods do not provide full recovery, resulting in sleep deprivation. Studies suggest that it can take up to 10 days to adapt to a night time work schedule.

Fatigue is a message to the body to rest. It is not a problem if the person can and does rest. However, if rest is not possible, fatigue can increase until it becomes distressing and eventually debilitating. The symptoms of fatigue, both mental and physical, vary and depend on the person and his or her degree of overexertion. Some examples include:

  • weariness
  • sleepiness
  • irritability
  • reduced alertness, lack of concentration and memory
  • lack of motivation
  • increased susceptibility to illness
  • depression
  • headache
  • giddiness
  • loss of appetite and digestive problems

Emergency responders, particularly those who are assigned to work for extended hours, must be aware of the limitations of the protective equipment they use and the allowable or safe duration of exposure to hazardous environments. It is not practical or safe to wear some forms of protective equipment for extended periods. Fatigue and heat-related illness are common problems.

How can I address these hazards?

When there is a choice, managers should limit the use of extended shifts. Working shifts longer than 8 hours will generally result in reduced productivity and alertness. Additional break periods and meals should be provided when shifts are extended past normal work periods. Tasks that require heavy physical labor or intense concentration should be performed at the beginning of the shift if possible. This is an important consideration for pre-emergency planning.

Managers and supervisors should learn to recognize signs and symptoms of the potential health effects associated with extended and unusual work shifts. Workers who are being asked to work extended or irregular shifts should be diligently monitored for the signs and symptoms of fatigue. Any employee showing such signs should be evaluated and possibly directed to leave the active area and seek rest. Employers should have plans in place to assist and address workers experiencing serious or severe effects of fatigue.

Make efforts, whenever feasible, to ensure that unavoidable extended work shifts and shift changes allow affected employees time for adequate rest and recovery. Extended shifts should not be maintained for more than a few days, especially if they require heavy physical or mental exertion.

Plan to have an adequate number of personnel available in order to enable workers to take breaks, eat meals, relax, and sleep. If at remote sites, ensure, as far as possible, that there is a quiet, secluded area designated for rest and recuperation.

Plan for regular and frequent breaks throughout the work shift. In addition to formal breaks such as lunch or dinner, encourage the use of micro breaks to change positions, move about, and shift concentration.

In addition to fatigue, employers must ensure that employees are not exposed to hazardous chemicals or other agents in excess of health standards. Working extended shifts may involve prolonged exposures to hazards which exceed established standards. Therefore, employers should implement measures to monitor and limit exposures. Those may include administrative controls such as limiting the time employees may remain at the response site; engineering controls such as clean locations for employee rest areas; or rest areas located sufficiently up wind of contaminated sites.

For additional information about hazards, prevention, and limitations on work hours, visit OSHA’s Work Hours, Extended or Irregular Shifts, and Worker Fatigue Safety and Health Topics page.