International Archives of

Int Arch Occup Environ Health ( 1982) 49:353-355 4 ' t~ ~{~, and

© Springer-Verlag 1982

Documents of International Meetings and Activities

Organization of Night Shifts in IndustriesWhere Public Safety is at Stake*

P Andlauer, J Rutenfranz, K Kogi, H Thierry, N Vieux, and G Duverneuil

At the 5th International Symposium on Night Shift Work held in Rouen, France,12-16 May 1980, under the auspices of the Scientific Committee on Shift Work ofthe Permanent Commission and the International Asociation of OccupationalHealth (PCIAOH, chairman, J Rutenfranz, secretary, W P Colquhoun), severalof the delegates decided to follow up C F Ehret's paper on "New Approaches toChronohygiene for the Shift Worker in the Nuclear Power Industry" with afurther meeting on "The Organization of Working Hours in Industries WherePublic Safety is at Stake" C F Ehret's paper was an assessment of thecircumstances of the accident which occurred at the Three Mile Island NuclearPower Plant in Pennsylvania, USA, at 4 a m on 28 March 1971 ' The meeting wasarranged with the agreement of the chairman of the scientific committee.

The circumstances of the accident at Three Mile Island indicate that the degreeof alertness of the control room operators was directly responsible for thesuccession of errors which eventually led to environmental pollution 2 .

The meeting was held on 28 November 1980 at St Vulbas, France Thosepresent were J Rutenfranz, chairman of the Scientific Committee, K Kogi,H Thierry, P Andlauer, N Vieux, members of the Scientific Committee, andG Duverneuil, representing the Association of Occupational Health Practitionersof the Lyon Chemical Industry.

The first part of the meeting was held in the training centre for control roomoperators in a nuclear power plant Operator behaviour and response to a criticalincident were studied through two simulated incidents which gave delegates a verygood idea of the degree of alertness required in such circumstances One of thesimulated incidents was in fact an exact reproduction of that which occurred atThree Mile Island, except for the fact that the actual incident took place at nightwhereas the training centre is open only during the day.

Subsequent discussion was based on the findings of the Commission of theAcademy of Science to the effect that on two occasions human error occurred andthat "an initial relatively innocuous material incident was considerably aggravatedby inappropriate measures "

* Meeting on 28 November 1980 at St Vulbas, Ain, FranceOffprint requests to: Prof Dr Dr J Rutenfranz, Ardeystr 67, D-4600 Dortmund, FederalRepublic of Germany

P Andlauer et al.

Our main point of concern was that the initial incident occurred at 4 a m.during the night shift and required the attention of operators who were then at theirfifth hour of the shift ( 11 p m -7 a m ) in an one-week shift cycle repeating everysix weeks The obvious question is whether this type of shift system is compatible,from the ergonomic and chronobiological point of view, with adequate operatorresponse The importance of this question becomes evident in the context ofoperators who are responsible not only for running an installation but also for thesafety of people living in the surrounding area.

All investigations concur in findings a phenomenon specific to night shift work,particularly where a high degree of mental alertness is required, which results in aloss of alertness after about 4 h of night work This is a disturbing situation becausecontrol room operators in the nuclear industry work a 9-h night shift ( 11 p m to 7a.m ) The phenomenon is obviously aggravated if the shift rotation cycle is long(e.g a week) and in instances where alertness is required beyond the second or thirdnight shift, which appears to have been the case at Three Mile Island.

Delegates were agreed on the absolute necessary of doubling up the night shiftwith two teams, with satisfactory rest facilities actually on the premises for the off-duty team In fact, such an arrangement for night shifts in industry would be theequivalent of the watch system practised for years in all the navies in the worldwhere, by definition, sailors sleep at their place of work.

Such a shift system could, naturally, be covered by regulations stipulating say 4to 4 5 h work per night shift, but a more spontaneous distribution of work betweenthe two teams would be preferable, provided, of course, that only one person was infull charge and that he was competent to give a final decision in any dispute Theessential requirement is that no operator should work more than 4 or 4 5 h total in thenight shift.

A third team would appear necessary, off-site but immediately available shouldthe operator in charge need to call them in.

The present system of making up for night work by having the night shiftworkers do day work on a reserve basis (between one and four days) is not of anyapparent value to their health The second night shift team could therefore beformed without any increase in manpower.

Furthermore, we consider it important that the shift rotation schedule shouldbecut down to a maximum of two or three days in order to prevent the desynchroni-zation which, as demonstrated by much research, inevitably occurs if the cycleexceeds three successive shifts.

Finally, from their privileged position, occupational health practitionersfrequently observe that quite spontaneously and almost openly, night shift workersmake arrangements amongst themselves to take "unofficial" rest periods Thispractice is more or less tacitly accepted by those in charge and is quite commonlyencountered not only in France but also in Japan, Holland and Western Germany.

The last subject discussed at the meeting covered the length of unbroken restcompatible with a thorough resynchronization of the biological functions (includ-ing mental functions) Some research shows that 6 weeks of unbroken rest peryear isa minimum requirement to compensate the adverse effects of shift work Thesefindings are confirmed by the fundamental notion that the adverse consequences ofshift work can in fact be subsequently reversed 3.

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Organization of Night Shifts in Industries Where Public Safety is at Stake

In conclusion, the group recommends the following action in respect oforganization of shift work in industries where public safety is at stake.

The provision of a second team for the night shift, with satisfactory restfacilities on the premises, obviating any night work in excess of 4 5 h.

The application of a short shift rotation cycle not exceeding two or threesuccessive shifts.

An unbroken period of 6 weeks annual leave, allowing complete recovery ofbiological functions affected by shift work.

Delegates strongly recommend that a higher standard of information beprovided by occupational health practitioners in order that the decisions made bynegotiators on both sides of industry are not detrimental to shift workers' health.

References

1 Ehret CF ( 1981) New approaches to chronohygiene for the shift worker in the nuclear powerindustry In: Reinberg A, Vieux N, Andlauer P (eds) Night and shift work Biological andsocial aspects Pergamon Press, Oxford New York Toronto Sydney Paris Frankfurt,pp 263-270

2 Payne J, Blake E, Fitz Gerald C ( 1979) The ordeal at Three Mile Island In: Nuclear newsspecial report, April 6, 1979 American Nuclear Society, La Grange Park, IL

3 Michel-Briand C, Chopard JL, Guiot A, Paulmier M, Studer G ( 1981) The pathologicalconsequences of shift work in retired workers In: Reinberg A, Vieux N, Andlauer P (eds)Night and shift work Biological and social aspects Pergamon Press, Oxford New YorkToronto Sydney Paris Frankfurt, pp 399-407

Received October 24, 1981 / Accepted October 26, 1981

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