My Simplistic View on Accident Cause, Investigation and Prevention

My Simplistic View on Accident Factors, Investigation and Prevention – Works for me!

slot machineReading all the articles on blogs and comments on various posts on Linkedin it seems that we all agree to disagree on most things and that is pretty healthy as long as we keep debating and keep an open mind. I really hope someone challenges me on what I am about to say.

NB – Thanks to George Robotham for pointing out that we should call them “Factors” NOT “Causes” otherwise we are on the back foot with our blame mindset Smile 


Two premises seem to currently be the hot topics for discussion, now that the Zero Harm debate has reached the most logical conclusion:

  1. Our systems and procedures are way too voluminous and complicated, developed by and for the person who has to enforce rather than the people who have to follow and comply – and we wonder why they don’t???
  2. Human Behaviour is apparently responsible for 99.9999% of all accidents or incidents and some believe we must try to blame and punish who ever we can???

As a young engineer thrown into the safety world with no idea, I quickly had to get up to speed when, on day 2, I was asked to investigate an incident where a dump truck had driven off a haul road and down the face of a quarry, badly damaging both driver and machine. I was swamped with opinion before I got to the site – “oh the driver wasn’t wearing seat belt”, the truck just got back from a service and they didn’t check the steering”, “the sun must have been in his eyes”, “he is too old to drive”, “he wasn’t trained properly”, “too busy fiddling with the new aircon”, The haul road cambers the wrong way”, “I told them they needed a bigger berm” etc etc.

Well after I went and got all the info and “facts” it seemed to me that many things had happened or gone wrong that morning and prior to it. Any one or a few of those things could normally (and do) happen in isolation and nothing much  happens, not even a near miss (or near hit). Since then I have heard about “Root cause analysis”, The Onion Skin”, “The Planets Aligning” and that back up my thinking at the time that it was only when a series of things go wrong simultaneously that the outcome is the serious incident. THERE ARE ROOT CAUSES (with an S) or more correctly FACTORS and not all directly human behaviour related (although if you had nothing better to do you could keep digging and blame the behaviour of the parents who conceived the child who went on to suggest that big holes could be cut in the ground to retrieve precious raw materials – if it weren’t for them this accident would NOT have happened).

The way I like to look at it now is that safety is a like a great big poker machine or slot machine. Even if we work for a zero harm company we take a risk (or gamble) when we go to work each day. The many wheels and hundreds of symbols on the poker machine are all the various components of our safety system: PPE, People, Plant, Environment, Procedures, Energy, Training etc. The lemons represent failures or incident contributing factors in each of those systems. All day we perform our tasks (pull the lever) and the wheels spin, occasionally a lemon may come up and we have a near miss, a few lemons and we have a minor incident – then, one day, ALL of the lemons line up – JACKPOT!!! The point is yeah, there may be behavioural lemons but they are almost harmless if there are fewer lemons in the other components of our system and vice versa.

I think that despite, what some may think, the more complicated your systems, the more lemons you will have and the more difficult it will be to find them.

I think then, whether you are looking at investigation or preventions, our job is to firstly identify all of those lemons. Each one would have or could have contributed to an accident and together they can be fatal. Take them out of only one wheel and we avoid a jackpot, but realistically all we can do is reduce the number in each wheel over time and increase our odds. Many are trying to only take the lemons out of the People wheel – you can never to that 100%. Others focus on the lemons in the Machinery wheel and ignore the other wheels.

To put this in a practical sense, I think the old FISHBONE, ISHIKAWA or CAUSE (FACTOR) and EFFECT DIAGRAM is the most useful incident investigation tool, particularly for the “non expert”. One should never stop an investigation or come to a conclusion until they have every bone of the fish with something on it. Don’t have to wait for an incident, this can also be used as a tool to identify all the “lemons” in your systems and prevent incidents.


Do you have any thoughts? Please share them below