What was the molten metal seen pouring out of the South Tower minutes before its collapse?

A December 2001 paper, "Why Did the World Trade Center Collapse? Science, Engineering, and Speculation," dismissed early reports about molten steel at the demolished World Trade Center. Dr. Thomas W. Eagar, a professor of materials engineering and engineering systems at the Massachusetts Institute of Technology, and his graduate research student, Christopher Musso, pointed out that the theoretical maximum temperature of a building fire (maximum 1000°C/1800°F) is not even close to the melting point of steel (approximately 1500°C/2750°F). And they noted that the observed black smoke emanating from the Twin Towers was consistent with a typical oxygen-starved building fire.

Eagar and Musso concluded that the actual temperature most likely remained below 650°C/1200°F. In so doing, they dispelled the myth that the jet fuel could have made the fires unusually hot, noting that it was "highly unlikely" that the temperature rose above 800°C/1470°F.

AE911Truth agrees that the jet-fuel-induced fires in the Twin Towers could not have melted steel.

But because more recent reports confirm the presence of molten steel and molten iron both during and after the 9/11 event, it must be determined what actually melted those two metals and in so doing demolished two of the world's tallest steel-frame skyscrapers.