Transcript Video 3: An introduction to work health & safety management (Chapter 5)

In this video we are going to learn about James Reason’s Swiss Cheese model. This theoretical model tries to explain the relationship between a hazard and a workplace injury. It can be used two different ways. Firstly, after an incident has occurred, it can be used to help us understand what went wrong so we can learn and immediately improve our safety system. Alternatively, we can use it before an incident occurs and it can help us identify any weaknesses developing in our safety system so we can fix these before something serious happens.

But who is James Reason and why did he develop this model? After much research and analysis on critical incidents (large scale ones resulting in many fatalities), UK-based Professor James Reason started thinking about what causes an incident – how do hazards and people interact? How does a potential hazard actually end up hurting people at work? Where does it go wrong? And, ideally, what strategies could we use to prevent an incident?

First we need to think about a hazard – a source of potential for harm.

Every workplace has many hazards – they are everywhere…machinery with blades that could cut off a worker’s hand, ladders that a worker could fall off or computer keyboards that might cause repetitive strain injury.

But, while hazards are everywhere; they are not injuring workers all the time or at the same rate – some organisations have catastrophes while others have low rates of injury even when workers are doing the very same job with exposure to the same hazards.

So while the threat of getting injured or harmed is always there, the risk to the worker (“The likelihood and consequence of injury or harm occurring.”) is not the same.

What could explain why some workers get injured and other do not? This is particularly interesting when workers are exposed to the same hazard while doing the same job. What is the difference about the individual or the workplace where the work is occurring?

Professor Reason and others concluded that it depends on the effectiveness of the organisation to identify the hazard, assess its risk (the actual potential for an injury to occur to a worker) and undertake measures to reduce the risk to the workers.

Interestingly, blaming the individual did not explain the incident nor did it lead to better safety outcomes.

What is unique to James Reason is that he had analysed workplace catastrophes he had learned that it was never just one person’s fault. Different issues in and around organisations affect the people involved and led to the incident. He was looking for a way to explain that we really shouldn’t blame-the-victim – because he could see that there were patterns – systems failures – and these were to blame. But how could he explain this?

Then, the idea of Swiss cheese model came to him!

James Reason first proposed that if a workplace were considered a block of cheese, then slices of cheese might represent layers of defence in a safety system including:

A people layer – safety focused workers with relevant values, behaviours and safe decision making

An engineering layer – with alarms, physical barriers and automatic shutdowns

A procedural layer – with instructions on safe work practices

An Administrative layer – ensuring people are hired with the right skills and provided the right training to perform tasks safely and are also, for example, given a safe work uniform.

However, Reason believes that there would be weaknesses in these layers occurring at any given time due to internal and external factors putting pressure on the organisation and its workers.

So James Reason proposes that we are not really looking at a solid block of cheese but, instead, we are looking at something like Swiss cheese. The first thing you notice with Swiss Cheese is that it has holes in it.

When workplaces develop weaknesses in their safety defence layers we can imagine the cheese getting holes in it. These holes are not always predictable or static they pop up when safety issues arise and disappear when safety issues are resolved, they can occur in different defence layers and within different parts of the organisation.

So, let’s imagine a block of cheese cut into slices – we are viewing the safety system in its distinct safety defence layers. Then, let’s pretend a hazard is like an arrow trying to shoot through the cheese to cause an incident.  Fortunately the hazard can only shoot through the cheese when all the holes in the defence layers line up.

In each of the defence layers, holes are constantly appearing and being repaired. Most of the time holes in each layer do not line up but when they do, you have an incident. The hazard will have had its opportunity to make contact with the worker and injury or harm will occur. Essentially when multiple layers of safety defences are weak, there are more holes in the cheese and a greater probability that the hazard arrow can shoot through more often to cause more incidents.

Organisations striving for good safety management try to repair the holes in the Swiss cheese as promptly as possible to minimise the probability of all the holes lining up and the hazard arrow shooting through.

So what specifically causes the holes in our safety cheese?

Professor Reason suggests that holes are created in safety defence layers by active failures and latent conditions combining.

Active failures are the unsafe acts committed by people who are in direct contact with the hazard. If you blame-the-victim this is all you would consider as it would just be that person’s fault. You would only examine the ‘people’ safety defence layer. They are either safe or unsafe people.

But with a systems approach we also examine Latent conditions – any decisions, processes and procedures that have the potential to weaken our safety defences and impact on a worker’s safety. This considers the engineering, procedural and administrative layers.

Active failures are ‘active’ – immediate and easily visible. Unless we are proactively using the Swiss Cheese Model to review our safety defence layers systematically and regularly, latent conditions can lay dormant in the system, they might only obviously emerge when the holes in the Swiss cheese match up causing an incident.

For example a manager decides to operate double shifts with the same crew. This management decision leads to tired workers. One worker hits a button on a machine –the hazard – out of sequence (an active failure) and this results in a colleague having his hand crushed (the incident). A procedural weakness is overlooking the fatigue in the operator who pressed the button. An engineering weakness is the fact that there was no layer of defence, no safety guard, to prevent the colleague’s hand being in the machine.

So how do we repair the holes in the Swiss cheese to stop the arrow shooting through?

Active failures are complex human-centric factors which makes them difficult to predict and control. However latent conditions can be identified and fixed before an incident occurs.

Keeping latent and potential active factors in check is key to safety management.

So how do we manage our safety defence layers? How do we avoid a blame-the-victim approach?

Most organisations choose to use a systems approach and therefore choose to have a safety management system.

In our next video we will learn about safety management systems, what they are comprised of and the different steps involved in setting one up. We will learn how to use safety management systems to identify and repair holes in the cheese.

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