181 multiple, but imperfect, layers of defence against accidents, as shown below.
Accidents occur when failures occur simultaneously in all the defensive barriers.
Hazard
Accident Engineering
Systems Behaviour
Hazard
Accident Engineering
Engineering Systems
Behaviour Behaviour
Figure 19.1 - Swiss Cheese model of accident prevention
Putting this into hygiene terms, we might have: an extraction system that is not operating at full capacity because of
lack of maintenance; a non-standard task that isnt fully covered by the normal safe working
procedure; and a worker who is inclined not to wear his PPE.
Any one or two of these measures might be sufficient to control exposure, but if all fail at once, over-exposure is likely.
19.2 Motivation and Behaviour Modification
In order to change behaviours it is necessary to understand and then address the factors which influence our behaviour. In recent years there has been an
increase in the use of behaviour modification approaches to safety and the lessons are equally relevant to occupational hygiene. Analysis and
modification of the behaviour of the worker involved in an activity has been
182 shown to be an effective way of reducing both accidents and reducing
occupational exposures. Behaviour can be simply understood in terms of the Antecedents - Behaviour -
Consequences A - B - C model see for example, Daniels A C, Bringing out the Best in People, 2nd ed. 1999, McGraw-Hill.
Antecedents create the initial motivation to act. They can include
instructions from the manager, and publicity or awareness campaigns from the occupational health and safety department. How such
messages are received will depend on other antecedents, including the workers experience of similar messages in the past, established ways
of working and other events taking place around the same time.
Antecedents set the stage for what happens next. Behaviour is the observable act. Unlike attitudes or intentions,
behaviour can be observed and quantified. It is objective. Consequences are what happen after the behaviour. The worker may
notice the consequences for themselves. For example, they may find it easier to do the job when their workplace is clean and tidy. Or they
may find that the PPE they had to wear made them uncomfortable. They may also get verbal feedback, positive or negative, from their
manager or colleagues. It is these consequences that determine whether the worker is inclined to repeat the behaviour.
Antecedents are valuable for initiating change, but only reinforcing consequences will guarantee repetition of the desired behaviour.
Often there are multiple and conflicting consequences which have to be weighed against each other. For instance, the individual may be aware that
by using a respirator he has reduced his exposure to airborne asbestos and so has reduced the risk of developing cancer at some point in the future.
However, he may have experienced difficulty breathing through the respirator or restricted vision that made the job harder. The general rule is that
consequences that are Soon, Certain and Positive outweigh those that are Late, Uncertain and Negative. So it is easy to see why many workers might
183 choose to discard the respirator, choosing the immediate benefits and
believing that the future negative consequences may never happen. Effective behavioural modification requires managers and health professionals
to find ways to minimise the negative consequences and reinforce the positive consequences of the desired behaviours. A common mistake is to revert to
the antecedents and to tell people again what they should be doing. A behavioural intervention can be planned in three distinct stages as follows:
1. Motivation: Firstly it is necessary to motivate individuals in order to get
them to want to change their behaviour. This is influenced by antecedents such as:
Their skills in the activity which they are undertaking and knowledge of the hazards associated with it.
Their beliefs about consequences of exposure to a particular hazard. Their beliefs about the performance and capabilities of control
measures The established ways of working health and safety culture.
2. Instigation: Once people are motivated they need to be supported to
enable them to change behaviour. This support needs to be both physical having time training, equipment etc and social from colleagues and
managers.
3. Maintenance: When a behaviour has been changed, efforts need to be
made to ensure that it doesn‟t revert back. Typically health and safety professionals focus on antecedents such as maintaining high levels of
awareness and refreshing knowledge and skills. However, the most important factor is reinforcing the positive consequences of the change.
Each of these stages of motivation, instigation and maintenance is in turn influenced by the circumstances within the job immediate work environment,
the organisation and outside organisationssociety.
184
19.3 Health and Safety Culture
