User:Cs32en/Sandbox/Sources

Members of the 9/11 Truth movement have filed Requests for Correction to the NIST report. Only one of their requests resulted in a change to correct an inconsistency between two parts of the NIST report. An unsuccessful appeal was then filed.

History
Controlled demolition theory proponents cite mainstream news reports on the day of the attacks that suggested explosions and secondary devices. Journalists and experts commenting on the events as they happened mentioned that the World Trade Center collapses looked like those caused by intentionally planted explosives. ABC News anchor Peter Jennings said "Anybody who ever watched a building being demolished on purpose knows that if you're going to do this you have to get at the under infrastructure of a building and bring it down" While watching footage of the collapse of WTC 7, CBS News anchor Dan Rather said "For the third time today, it's reminiscent of those pictures we've all seen too much on television before when a building was deliberately destroyed by well-placed dynamite to knock it down." Some of these suggestions would later be retracted or revised. In a notable example, the Albuquerque Journal quoted Dr. Van D. Romero, an engineer who said that the collapses looked "too methodical" and that "some explosive devices inside ... caused the towers to collapse", speculating that the collision of the planes into the towers was a diversionary attack intended to attract emergency personnel to the scene, followed by the detonation of "a relatively small amount of explosives placed in strategic points" of the towers as the primary attack. He soon withdrew this assessment and later said he had been misquoted: "I only said that that's what it looked like."

The theory was first suggested in October 2001. An early book-length treatment of the hypothesis inspired both David Ray Griffin's critical inquiry as well as the Popular Mechanics investigation of 9/11 conspiracy theories.

An August 2007 Zogby poll found that 4.8% of Americans believe that "certain US government elements actively planned or assisted some aspects of the attacks".

In June 2008, Arizona State Senator Karen Johnson delivered a letter to the office of U.S. Senator John McCain asking him to meet with a group of professionals to discuss the events of 9/11. She also gave a speech on the floor of the Arizona Senate that included her support for the demolition theory, its proponents, and its relevance to current foreign policy in the US. Johnson said in her speech: You don’t have to embrace every theory about 9/11. Indeed, there are some that should be soundly rejected. But if you believe, as these scientists, architects and engineers do, that the buildings were brought down by explosive demolition, then you must also agree that we need a new investigation. I have no preconceived notions about who did it and I am not pointing the finger of blame at anyone. But I do think that the worst attack on U.S. soil in American history deserves the best investigation possible. In April 2008, a letter by Steven Jones, Frank Legge, Kevin Ryan, Anthony Szamboti, and James Gourley was published in an online civil engineering journal. In October 2008, an essay describing what the author sees as fundamental errors in a Bažant and Verdure paper was published in the Journal of Engineering Mechanics by James Gourley.

World Trade Center Seven
7 World Trade Center was a 47-story steel-framed skyscraper that stood across Vesey Street north of the main WTC complex. Its tenants included Salomon Smith Barney (which leased 44% of the available office space), ITT Hartford Insurance Group (8%), the Securities and Exchange Commission (8%), the Secret Service (5%), and the Internal Revenue Service (IRS) Regional Council (3%). Smaller tenants included the Central Intelligence Agency (CIA) and the Department of Defense, though these shared a single floor with the IRS. Altogether, U.S. local, state, and federal government agencies occupied 11 of the overall 47 floors, or about 28% of the available 39 floors of office space. Though damaged by fires which burned for seven hours, it was not hit by a plane, and collapsed at about 5:20 p.m. EDT on the evening of September 11, 2001.

Some journalists commenting on the nature of the collapse of WTC 7 said that it resembled a controlled demolition, although the explanation that fires in the building, started by falling debris from the collapse of WTC 1, had caused the structure to fail, quickly emerged.

Proponents of controlled demolition often emphasize the collapse of WTC 7 because its collapse looked like a bottom-to-top conventional controlled demolition, as opposed to the more explosive top-to-bottom collapses of the two main towers. Support for this theory comes from features argued to have been visually observed in the collapse--the speed of the collapse, the way it fell down vertically and symmetrically, the rapid onset, and the way the center of the roof fell first. Steven Jones claims that the presence of sulphur is evidence that indicates the use of explosives such as thermate, along with reports of molten metal and extremely high temperatures in the rubble.

Hugo Bachmann and Jörg Schneider, professors emeritus of structural engineering at the Swiss Federal Institute of Technology, believe that WTC 7 was intentionally demolished based on video footage. The 9/11 Family Steering Committee also asked what happened to WTC 7 in their 'Questions Regarding the 9/11 Commission Interview of Mayor Rudy Giuliani,' asking, "On 9/11, no aircraft hit WTC 7. Why did the building fall at 5:20 PM that evening?"

World Trade Center developer Larry Silverstein said, "Hopefully this thorough report puts to rest the various 9/11 conspiracy theories, which dishonor the men and women who lost their lives on that terrible day." Richard Gage, leader of the group Architects and Engineers for 9/11 Truth said, "How much longer do we have to endure the coverup of how Building 7 was destroyed?". James Quintiere, professor of fire protection engineering at the University of Maryland, College Park, who does not believe explosives brought down the towers, questioned how the agency came to its conclusions, remarking, "They don't have the expertise on explosives." Following the NIST final draft on Building 7 in August 2008, a group of demolition proponents submitted a response challenging several points of the draft. .

On November 20, 2008 NIST released the final report on the collapse of World Trade Center 7. For the final report in "response to comments from the building community" NIST ran additional analysis to "see if the loss of WTC 7’s Column 79—the structural component identified as the one whose failure on 9/11 started the progressive collapse—would still have led to a complete loss of the building if fire or damage from the falling debris of the nearby WTC 1 tower were not factors. The investigation team concluded that the column’s failure under any circumstance would have initiated the destructive sequence of events."

The controlled demolition theory is also offered to explain dramatic collapses of the two main towers of the World Trade Center complex on September 11, 2001. It emphasizes the speed, symmetry and totality of the collapses, which, it suggests, could not have been caused by the airplane crashes alone. The effects of the fires and the progress of the collapses after they began have been the main areas of contention.

Main towers
Supporters of the theory claim that anecdotal evidence of molten steel found in the rubble of the collapse and a stream of molten metal that poured out of WTC2 before it collapsed are evidence of temperatures beyond those produced by the fire (which was not expected to be hot enough to melt steel). Steven Jones has argued that the molten metal may have been iron, a byproduct of a thermite reaction. Thermite reactions can reach temperatures of up to 4500°F (2500°C), well beyond the temperature (approximately 2732°F (1500°C)) required to melt structural steel. NIST found that the condition of the steel in the wreckage of the towers does not provide conclusive information on the condition of the building before the collapse and concluded that the material coming from WTC2 was molten aluminum from the plane, which would have melted at lower temperatures than steel. They also pointed out that cutting through the vertical columns would require planting an enormous amount of explosives inconspicuously in highly secured buildings, then igniting it remotely while keeping it in contact with the columns.

The controlled demolition theory is also offered to explain a belief that the towers collapsed close to free fall speed. Most estimates agree that the structures offered little resistance to the progress of the collapses and that they took about 50% longer than a free falling object dropped from the tops of the towers. Without explosives to destroy the internal support structure of the WTC towers, argue proponents of controlled demolition, the fall of the towers would violate the principle of conservation of momentum. Others say that these claims are only supported by intuition without any quantitative analysis. They point to their own analyses posted on a website suggesting that the fall may be explained without violating the principle of conservation of momentum and without requiring any explosives.

Supporters of the controlled demolition theory often emphasize that NIST did not simulate the structural response of the lower parts of the buildings, which they find of primary interest, but do not analyze either.

Some proponents suggest that the energy required for this expansion alone (ignoring the energy needed to slice the steel and pulverize the concrete and other materials) exceeded the gravitational energy available by 9.7 × 1012 J to 4.2 × 1013 J. This corresponds to extra energy of about 2000 to 10000 tons of TNT, or 40 to 200 times the yield of the most powerful conventional bomb.

Notable proponents
Webster Griffin Tarpley has devoted a chapter of his book 9/11 Synthetic Terror to the theory. Kevin Ryan, who was fired from his job at Underwriters Laboratories for voicing his criticism of the official investigation, has also contributed a chapter to the Griffin and Scott volume. While his work remains largely self-published, Jim Hoffman's detailed web site, 9-11 Research, is often cited by proponents of the controlled demolition conspiracy theory as an inspiration.

Criticism of the NIST Report
Criticism of the NIST Report plays a prominent role in presentations of the theory. Critics point out that the report does not provide an account of the structural behaviour of the towers after the collapses began. This is important because "much of the external evidence for controlled demolition typically comes after collapse initiation". It is argued that not modelling the totality of the collapses allowed NIST to ignore evidence of demolition, such as the complete, rapid and symmetrical nature of the collapses, the observed explosive "squibs", the early drop of the North Tower antenna, and the pools of molten metal found in the rubble. Kevin Ryan's criticism of the NIST investigation and subsequent report is often mentioned in this regard. Jones also criticises NIST for "tweaking" the computer simulations of the pre-collapse sequence "until [it got] the desired result.” Jones goes on to quote the NIST report itself as proof for this claim, "''The Investigation Team then defined three cases for each building by combining the middle, less severe, and more severe values of the influential variables. Upon a preliminary examination of the middle cases,it became clear that the towers would likely remain standing...The more severe case was used for the global analysis of each tower..To the extent that the simulations deviated from the photographic evidence or eyewitness reports''"