You want simple language?
“I do believe that it's the first time in history that fire has ever melted steel."
Rosie O'Donnell
Well, that WOULD be simple. Problem is, it would also be incorrect. Steel buildings get fireproofing applied to them for that very reason ... so that a bad fire won't cause the structure to collapse. The steel doesn't have to "melt" ... all it has to do is get hot enough to change the temper, and down she comes.
As a specific example, back around 1970 there was a catastrophic fire in the building housing the Yale School or Architecture. That building was reinforced concrete throughout, which is generally considered rather fireproof because the steel is protected from heat by several inches of concrete. Problem is, it was the end of the year, the students were all cranking away on their thesis projects, and the building was chock-a-block full or paper, paint, balsa wood, glue, and various other flammable materials. The fire on the upper stories was hot enough that it did, in fact, melt the steel (at least to the point of structural failure, although not literally puddles of liquid metal).
But, the only thing Rosie is an expert on is shooting off her fat, ugly mouth.