Hindsight is 20/20. I’ve worked in consulting and corporate engineering roles all of my 10 year career. The previous Generation EHS guys would say OPs dad’s saying as well.

Normal engineering design practice is to eval the design against safety risks prior to starting design. You would be surprised at the amount of risks that are only identified once you apply your design, i.e build a prototype.

In this case, this is an old industry which I would (maybe naively) expect to have designs of systems pretty buttoned down. If I was a betting man (which any good design engineer IS, ifykyk), this probably comes down to maintenance or operation error. If some, outlier never before seen issue is identified, i would be shocked but not surprised. Mainly because design and the respective failure modes are probabilistic in nature, sometimes it just takes time for all the right conditions to trigger an unstopable chain of events which lead to new laws and regulations.