I haven't heard anyone study any kind of liquid metal embrittlement in the collapse of the twin towers. Reportedly a little bit of molten Zinc came into contact with the steal beams of the flexborough factory in England, and the factory collapsed killing dozens. In the conspiracy theories of a controlled explosion (thermite) I have heard there were large quantities of zinc in the ground.

Other metals could contribute to LME, but highly destructive metals like Mercury and Gallium are pretty much banned on planes/airports.