Loose Change versus Popular Mechanics on 9/11 - score one for Loose Change

I did not expect to write the headline above, but that's the way it turned out when I tested one randomly-chosen contradiction between the two sides.

"Loose Change" is a documentary with an IMO ridiculous claim about 9/11 being a conspiracy. Popular Mechanics wrote a rebuttal which became a book. Democracy Now hosted a debate, and this came up regarding the Loose Change claim that Underwriter Laboratories certified the Twin Towers steel as something that wouldn't melt or weaken under the heat from the fires:

DAVID DUNBAR: In fact, Underwriter Laboratories does not certify structural steel.

DYLAN AVERY: Oh, okay.

JASON BERMAS: I would disagree with that.

Okay, seems like there's no gray area on this question. I looked up Underwriters, and found several relevant examples of certifying steel for structural uses. I emailed Dunbar about it two weeks ago, and have heard nothing so far.

So this doesn't change me from being a skeptic about the conspiracy theory, but it's a little disconcerting how this seems to have turned out. I hope Popular Mechanics did better quality control on other things they assert with equal authority.

To put some fuel on the fire, I'm going to send this entry to the Skeptic's Circle. Folks there might be able to explain how Popular Mechanics is right - otherwise, they would just know not to use this argument when talking about 9/11.