The melting point of Zinc is indeed 420 degrees, but Celsius not Fahrenheit. I am not sure that my stove top can reach those temperatures. You are right about it being toxic, I'll keep that in mind if I leave the country and make gun metal.
The article was from apparently 1992, before the twin tower attack. Of course it wasn't geared towards proving or suggesting the cause of the collapse of the twin towers, but showing that the phenomena of liquid metal embrittlement of molten zinc on steel was already documented and didn't need my repeating. You chose to focus too far into one specific example, instead of as general concept.
A36 steel is one of the types of steel that was used in the world trade center. Galvenized steel can include A36 steel like seen in the above article, but galvanization makes structural steel weaker. There are standards that try to minimize LME during the galvanization process but it can still occur. Supposing that sufficient molton zinc (or even lead, or some other metals) came into contact during the impact then the fuel combustion would make the temperatures by ripe for the LME but there would be substantial additional stress if not from the impact then from the structure itself enhancing LME potential.
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