That's a nice example of the prevention paradox at work. You do your work well. Nothing happens for a while. You get laid off. Then eventually something happens...
And that's why you shouldn't just be testing manually but you should be writing automated tests that run again and again, even long after you have moved on.
If ever there was the need for Chesterton's Fence, this is it.
It looks like amount wise they got lucky. I wonder how they were transported for that photograph. And whether or not the person that made it knew how far away from something really bad they were. That gives me the creeps.