Many people claim there was molten metal at Ground Zero, based on quotes like this one (see the link for more):

An article in The Newsletter of the Structural Engineers Association of Utah describing an speaking appearance by Leslie Robertson (structural engineer responsible for the design of the World Trade Center) contains this passage:

“As of 21 days after the attack, the fires were still burning and molten steel was still running”
http://911research.wtc7.net/wtc/evidence/moltensteel.html

Although this is generally attributed to Leslie Robertson, it’s not at all clear that he ever said these words. The quote actually comes from an article by James M Williams, recounting a keynote address that was delivered by Robertson, so it’s at best a second-hand interpretation of what he said. 

What is the truth, then? We sent an email to LERA, Robertson's engineering firm, in an effort to find out:

I have a question regarding some claims in the October SEAU Newsletter (http://www.seau.org/SEAUNews-2001-10.pdf)

In this article it is stated that

"As of 21 days after the attack, the fires were still burning and molten steel was still running."

This statement has been attributed to Leslie Robertson and used to support some of the more unusual claims regarding the 9/11 attacks. I was wondering, is this statement correct, or could you clarify it at all?

And a short time later, an email arrived from Leslie E Robertson himself:

I've no recollection of having made any such statements...nor was I in a position to have the required knowledge.

Brief, but direct: he doesn’t recall making the statement, and wouldn’t have known if it was true anyway. 

Previously we concluded that the phrase was Williams alone, but it seems that’s not entirely true. James Williams sent us his notes from the Robertson address, and it does make reference to molten metal. Only that’s it: he wrote “molten metal - still running”, not “molten steel”. (We’ve made the notes available here, with permission).

Robertson says he didn’t use the “molten steel” quote, then, and Williams notes don’t disprove this. The key is to find out where the “molten metal” line came from. Was it something Robertson said, and has since forgotten? Or a note in response to a photo? We’re trying to obtain the original Powerpoint slides of the address, which should offer a clue, but in the meantime this story should be regarded with caution: it’s clearly far from definitive evidence of molten steel at Ground Zero.