Issue 6: October 1998



(Contractor: Scottish Centre for Infection and Environmental Health)

The Control of Substances Hazardous to Health (COSHH) Regulations (1994) and the European Community Directive on the Protection of Workers from Exposure to Biological Agents at Work (1990) both require assessment of the risks resulting from exposure to hazardous substances and micro-organisms due to working practice or accidental exposure. Previous surveys have identified the trends in the incidence of laboratory-acquired infections within NHS laboratories and have been useful in highlighting a number of areas of concern. However, the lack of follow-up on non-responders to such surveys and the emphasis on NHS clinical laboratories has restricted the usefulness of the data for quantifying the risk of infection experienced by workers potentially exposed to pathogens in different types of laboratory. HSE therefore commissioned this retrospective survey, covering the period 1994 to 1995, to provide information about the risk and incidence of infection in a wide range of clinical laboratories.

Questionnaires were sent out to 659 organisations thought to have laboratories. A total of 557 responses were received, of which 397 were from organisations with laboratories. Only nine cases of possible or probable occupationally-acquired infections were reported by these laboratories. The survey covered over 55000 person-years of occupational exposure. The overall infection incidence rate found was 16.2 per 100000 person-years compared with 82.7 per 100000 person-years found in a similar, previously reported, survey covering 1988 and 1989.

Infections were found to be most common in females, in relatively young staff, in microbiological laboratory workers and in scientific/technical employees. Gastrointestinal infections predominated, particularly shigellosis, but few specific aetiological factors relating to work practice were identified. No hepatitis B cases were reported.

The results of this survey are encouraging, and whilst there remains room for improvement, the findings reflect well on standards of infection control in UK laboratories.


(Contractor: System Concepts Ltd.)

In order to investigate the problems associated with DSE use, a questionnaire survey of DSE users was carried out. The questionnaire was designed to collect information relating to: the symptoms of discomfort associated with DSE use; problems associated with the DSE work environment; and general information about the DSE user. The responses of 968 individual DSE users from 27 companies were received and analysed.

A key finding of the study was that DSE work lead to frequent complaints of discomfort. Around 1 in 3 users complained of general fatigue, whilst around 1 in 5 complained of headaches or of neck, shoulder, hand, arm or eye discomfort. The research showed that the amount of time spent using DSE was a good predictor of discomfort, and users who spend more than 75% of their work time using DSE were significantly more likely to complain of wrist, hand and finger discomfort than lighter users. DSE-critical users (such as data entry clerks) were significantly more likely to complain of headaches, focussing difficulties and discomfort in the legs, shoulders and wrists than discretionary users (such as managers).

Users who had attended DSE training were less likely to complain about discomfort symptoms, particularly users who felt the training had been appropriate and who had subsequently applied the training in the workplace. For the group of DSE users surveyed, work breaks appeared to have no effect on reports of discomfort, even when DSE users who worked for 3 hours without a break were compared to those who worked for less than 1 hour before having a break. Users provided with spectacles for DSE use were significantly more likely to complain about a range of visual discomfort symptoms. Over half of the users were critical of the air quality and ambient temperatures in their offices and 1 in 3 of users were dissatisfied with reflections, glare and the overall light levels in their offices.


(Contractor: University of Wales Swansea)

Although there would appear to be a wide variety of shift systems in operation in the UK, there is a strong bias towards the use of rotating rather than permanent systems to cover the 24-hour day. Approximately 75% of rotating shift systems involve 8-hour rather than 12-hour shifts. Literature suggests that the use of 12-hour shifts is increasing, mainly due to pressures from the workforce who see advantages in the potentially increased proportion of rest days.

The beneficial effects of 12-hour shift systems reported in the literature and obtained from this study are largely limited to subjective measures such as improved mood and family and social life and reduced psychological health problems, including stress. However, some objective benefits include reduced commuting costs and time, and a reduction in the number of shift handovers. The disadvantages of 12-hour shift systems centre largely on fatigue and safety problems, although this study did find some evidence of reduced physical health. In line with previous research, the study also confirmed the inferiority of performance and mood of workers on 12-hour shifts during the early hours of the morning. A similar inferiority of response was also found in the early afternoon, another time at which the 12-hour workers had been on duty for rather longer than their 8-hour shift counterparts.

These effects are probably due to the combined effects of the length of time the individuals had been working for and the circadian rhythm known to exist in sleep propensity. The results of this study also indicated that a shift changeover at 07:00 caused considerably fewer problems than one at 06:00. Little evidence was found to support the view that forward rotating 8-hour systems were preferable to backward rotating ones. Neither was any strong evidence found to support the inclusion of a break of more than 24-hours when changing from day shifts to night shifts on a 12-hour system, although there was evidence of a culmative detrimental effect caused by successive 12-hour night shifts.

The results concur with other published research, that the use of 12-hour shift systems should be avoided where there is risk to the public. The popular 12-hour system of two-days and two-nights on and four-off (which requires four teams averaging a 42-hour week to provide continuous cover), would appear to have much to commend it in many work situations. However, the advantages of this type of shift system should not be negated by the increased use of overtime. Many of the advantages of the 12-hour shift system stem from the increased number of rest days and allowing these to be worked as overtime may turn this strength into a weakness.


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Published on internet on 6/1/99

Updated 2021-03-30