The photograph we are about to examine is from a report by company called Liro. The following are some quotes from their homepage:

Achitecture, engineering and construction management firm since 1984...

LiRo is committed to becoming a premier, nationally recognized leader in the design and construction management of infrastructure, facilities and environmental projects.

"One of the top 50 construction management firms in the United States..."
Engineering News Record

In the report, there is a photograph of some metal burning in the foreground. Next to it, this paragraph below can be found:

Red Hot Debris. The removal of debris from the collapsed area requires the safe lifting and maneuvering of very heavy steel beams, often twisted and tangled from the force of the collapse. Some beams pulled from the wreckage are still red hot more than 7 weeks after the attack, and it is suspected that temperatures beneath the debris pile are well in excess of 1,000°F.
http://www.liro.com/lironews.pdf

The source of this photograph would appear to be solid and the given date is October 21st 2001. I then enhanced the image to enable identification of the material.

Enhanced Image of Metal Observed by Liro

Now perform a quick comparison:

Reference Image for Steel

I can confirm Liro's identification that these beams are steel. The temperature indicated by the colour of this beam places it well above 1000C. Again, as we will observer later, this is physically impossible given the ground temperature.