The ultimate problem is the breakdown in trust of our institutions to get this right - the overriding incentives are wrong at every level. Burning a product because it would have otherwise needed to be recovered and transported under pressure seems like exactly the kind of amoral tradeoff a company would take, not particularly caring about the combustion products apart from what they can legally get away with.
As far as the actual technicals, your assertion that "the combustion products are simply much safer than the products that were leaking" would seem to just be the opposing take in a fact-free debate. First, combustion products have been dispersed in the air. And second, with large quantities of anything, trace amounts of impurities or other combustion products become significant.
> Burning a product because it would have otherwise needed to be recovered and transported under pressure
I don't think that's correct. It was leaking. No recovery was feasible. The options at hand were "let it leak" or "burn it", and burning it was the right choice.
Now, maybe you don't believe that. And of course I believe it on faith. But real chemical engineers are making these decisions, not yahoos on HN. And the fact that you perceive a "breakdown in trust" of those engineers doesn't make them wrong. If you want them to be wrong you need to provide evidence yourself.
I do not see how leaking would preclude recovery. It's likely "feasible" is shorthand for economically feasible. And from the manifest linked elsewhere in the thread, all but one vinyl chloride cars are listed as "car did not leak".
> the fact that you perceive a "breakdown in trust" of those engineers doesn't make them wrong
No, what would make them wrong (as in, not doing everything they can to minimize harm) is the orders/incentives coming down from management. Boss says to do the cheapest option possible, they look at the top-line combustion products and regulations regarding releasing them, and sign off on the cheaper burn plan. We get the same thing in software with the zeitgeist of user surveillance. It's an overwhelming ethical violation, but everyone's gotta eat and if you rock the boat it costs you personally.
> If you want them to be wrong you need to provide evidence yourself
I'm not responsible for releasing chemicals into residential areas, nor for lighting them on fire. It's incumbent upon the railway and responders to prove that their actions were justified and correct in minimizing the damage to bystanders.
The cars weren't leaking, they were vented and ignited because they had the potential to explode otherwise. The other cars were burning from the crash, and an explosion would make the situation exponentially worse.
As far as the actual technicals, your assertion that "the combustion products are simply much safer than the products that were leaking" would seem to just be the opposing take in a fact-free debate. First, combustion products have been dispersed in the air. And second, with large quantities of anything, trace amounts of impurities or other combustion products become significant.