The next debate took place on June 18, 2008, between Richard Gage, AIA, and Mark Roberts (a.k.a 'Gravy” on the James Randi Educational Forum) on the TV access show “Hardfire” with host John Clifton, past chair of the Libertarian Party of New York. Mark Roberts, a New York tour guide, said he has “no specific expertise” in 9-11 matters but became interested in 2006 when he heard some of the “conspiracy theories” and found them “suspect.”Excerpt from "Waiting for Seven: WTC 7 Collapse Warnings in the FDNY Oral Histories" by Prof. Graeme MacQueen:
Roberts could barely contain his hostility towards Gage, accusing him of lying several times and impugning his motives. The ill will Roberts brings to the discussion is evident in many of his online posts where he goes by the name of “Gravy.” One such post on a James Randi Educational Forum refers to “Gage and his gang of lazy, lying, despicable creeps,” which indicates that he doesn’t just disagree with his opposition; he despises them.
Towards the beginning of the debate Roberts said of Gage, “He's got a 542-slide presentation that he encourages everyone to see on his website.... I found 311 false statements, 114 misleading statements, and 137 logical fallacies.” He did not elaborate. Roberts took the approach that NIST fully explained everything; that anomalies, such as witnesses hearing explosions, simply didn't happen or the witnesses were mistaken. He also said the evidence of foreknowledge that Building 7 would collapse was simply a matter of experts thinking the building might fall because it had been damaged.
Mark Roberts, for example, has set forth a detailed collection of collapse warnings, many of which are drawn from the oral histories of the New York Fire Department,  and has tried to use these to support his hypothesis of a natural collapse. Ryan Mackey has used this material in a similar fashion. Since I find Mackey’s reasoning more clear than Roberts’ I will take him in this paper as representative of this position.Response to Mark Roberts' “WTC Not a Demolition” video
He oughta know better: Mark Roberts and the iron spherules
Email debates, and more about Mark Roberts
Mark Roberts, an Apologist for EPA Lies
Mark Roberts: 9/11 "Debunker" or just Dishonest?
Factual back-up, sources, and further research materials.