There is a classic pattern with incident reports that's worth paying attention to: The companies with the best practices will look the worst. Imagine you see two incident reports from different factories:
1. An operator made a mistake and opened the wrong valve during a routine operation. 15000 liters of hydrochloric acid flooded the factory. As the flood started from the side with the emergency exits, it trapped the workers, 20 people died horribly.
2. At a chemical factory, the automated system that handles tank transfers was out of order. A worker was operating a manual override and attempted to open the wrong valve. A safety interlock prevented this. Violating procedure, the worker opened the safety interlock, causing 15000 liters of hydrochloric acid to flood the facility. As the main exit was blocked, workers scrambled towards an additional emergency exit hatch that had been installed, but couldn't open the door because a pallet of cement had been improperly stored next to it, blocking it. 20 people died horribly.
If you look at them in isolation, the first looks like just one mistake was made, while the second looks like one grossly negligent fuckup after another, making the second report look much worse. What you don't notice at first glance is that the first facility didn't have an automated system that reduced risk for most operations in the first place, didn't have the safety interlock on the valve, and didn't have the extra exit.
So, when you read an incident report, pay attention to this: If it doesn't look like multiple controls failed, often in embarrassing/bad/negligent/criminal ways, that's potentially worse, because the controls that should have existed didn't. "Human error took down production" is worse than "A human making a wrong decision overrode a safety system because they thought they knew better, and the presubmit that was supposed to catch the mistake had a typo". The latter is holes in the several layers of Swiss Cheese lining up, the former is only having one layer in the first place.
I wish I had more upvotes for you. While the swiss cheese model is well known on HN by now,your post goes a little bit deeper. And reveals a whole new framework for reading incident responses. Thanks for making me smarter.
Chernobyl reactor 4 explosion is a bit like this. Safety rules were ignored, again and again and again and again, two safety controls were manually deactivated (all within 2 hours), then bad luck happened (the control rod holes were deformed by the temperature), and then a design flaw (graphite on the extremity of the control rods) made everything worse until the worse industrial catastrophe of all time.
I don’t understand the point of this theory. Not having safety controls is bad, but having practices so bad that workers violate N layers of safety protocol in the course of operation is also bad. They’re both problems in need of regulation.
The failure rate of an individual layer of Swiss cheese should be bounded under most circumstances but not all. So you should probably have more layers when hazards cannot be eliminated.
Classic Swiss Cheese model. How many times did someone cross the road, wearing dark clothing, with an eyepatch on, but the operator was paying attention and successfully avoided them.
> The combination of coincidences is striking
Why?
Someone decided to walk across the road, was wearing dark clothing, had an eyepatch on so he couldn't see one side of the road well, and was struck by a forklift while the operator was on the phone.
What combination of coincidences is striking? People are careless all the time.
Timing and circumstance (especially the eyepatch.) It's basically a scene out of a movie.
It's not striking because a person who wears an eye patch and has a tendency towards dark clothing is stastically more likely to be involved in an accident where seeing and being seen are important.
The original commentor found it striking.
This is the plane picture meme
One boss (ship's captain for context, but I think this applies more widely) would call careless slip-ups "lemons", as in one armed bandits. One lemon was fine, happens from time to time. Two was a cause for concern. Three and everything stops to evaluate what's going on and for people to reset.
Knowing about the swiss cheese model is great, but you also need to have some heuristic about when those holes might line up and bite you. Typically it's when people are rushed, stressed and tired and you have to be able to spot that even when you're rushed, stressed and tired.
That said, forgetting to put on your hi-vis might be a careless error, but walking outside of marked pedestrian zones and operating a forklift while using a phone absolutely aren't! The forklift driver fleeing the scene makes me think safety culture had to be abysmal.
> The combination of coincidences is striking
It would only really be a striking coincidence if each of these elements is a rare occurence - although if the site has a poor safety culture and this sort of stuff is happening all the time, it becomes less of a coincidence and more of an inevitability.
In the UK for example sites generally mandate hi-vis vests, establish pedestrian walk routes, ensure visitors can't walk straight into the warehouse without supervision or training, and ban using mobile phones when using any form of MHE - so if sites had good safety standards and enforced all this, then the chance of it happening would be much smaller than a site that didn't enforce all this (Just saying this is how it is in the UK as my experience all this is less common in the USA - although no doubt many sites operate the same).
If a site lets people wear what they want and does not stop MHE operators from using phones and lets a visitor freely walk around the warehouse... I don't know if a person getting hit at that stage is a coincidence IMO (regardless of the eye patch).
ok but also something is still not adding up here - sure the operator was distracted, but you a presumably functional CEO are crossing the road, and you cant hear a forklift moving/dont think to look like at all? these things dont move that fast esp on a worksite
There is probably constant noise on a worksite so there was nothing special to notice.