What on earth does Swiss cheese have to do with work health and safety?
Good question. Let’s back up a bit so we can put it all in context. We have recently launched our new Strategic Incident Analysis (SIA) training here at AlertForce. SIA is a set of strategies for figuring out why a incident occurred, how to prevent it from happening again and how to use the lessons learned to continually improve workplace safety and mitigate risk in the future. Developed in consultation with experts in the field of incident root cause analysis and risk mitigation, our SIA course takes the principles of Incident Cause Analysis Method (ICAM) and delivers them in a fresh new, accessible and practical framework.
One of the key principles of ICAM is the Swiss Cheese Model developed by Professor James T. Reason. It’s got nothing to do with it being anyone’s favourite sandwich filling and everything to do with understanding how accident causation works in the context of risk management. This is – briefly – how it works:
- Reason compares human systems to layers of swiss cheese
- Each layer is a layer of defence against mistakes and failures
- There are “holes” in each layer because no system is perfect, and humans are fallible, but if something gets through, it usually gets stopped by another layer of defence
- Things go wrong when failures are able to get through every layer i.e. where the holes in each slice of Swiss cheese line up
- This is what leads to workplace accidents and incidents
Ideally, when it comes to workplace safety, we want all our systems or layer of defence to be intact. In reality, however, all systems have weaknesses – the “holes” in the cheese. We put into place extra layers around those weaknesses but occasionally circumstances collide in such a way that all the weaknesses coincide and the whole defence structure is breached. When the holes momentarily align, the circumstances are in place for what Reason calls “a trajectory of accident opportunity.”
These failures in the defence layers arise from a combination of two factors:
- Active failures
- Latent conditions
Active failures are the unsafe acts of people connected to the system e.g. slips and fumbles, mistakes and lapses, violations of codes or procedures.
Latent conditions arise from flaws or frailties in the wider system e.g. decisions made by management or designers, problems within workplace culture, outdated policies and procedures. They are elements that can remain dormant in the system for a long time before coming to light when an incident occurs. Here’s an example:
- A dump truck reverses into some scaffolding on a construction site causing damage to the vehicle and the structure and injuring a worker on the ground.
- The active failure here is most likely the driver’s failure to adequately control the truck – perhaps the driver didn’t use a warning device, didn’t check the area before moving, and/or didn’t adequately communicate with workers and traffic control staff on the site.
- Upon further investigation it is found that the driver was insufficiently trained to operate that kind of heavy vehicle but was under pressure from supervisors to get the job done by a certain time. The latent failure here then is management’s focus on productivity at the expense of training and safety and the workplace culture that meant the employee did not feel empowered to question the direction they were given.
- The outcome could be a review of training standards, with more rigorous training put in place, and the implementation of updated safety protocols to ensure inexperienced workers are not charged with jobs they are not qualified to do.
This is a very simple example but one than illustrates the layers of responsibility involved and the importance of looking beyond the “who’s fault was that?” question and examining more deeply the larger factors at play in any accident. Addressing those latent conditions – we might think of them as the holes in the cheese that have been there so long we barely even register them anymore – is central to the continual improvement of safety in any workplace.
Once failures in the various layers of defence have been analysed and dealt with, your Swiss cheese will start looking a bit more like a block of good, solid parmesan.
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