World Trade Center controlled demolition conspiracy theories

World Trade Center controlled demolition theories contend that the collapse of the World Trade Center was not solely caused by the airliner crash damage that occurred as part of the September 11, 2001, attacks, and the resulting fire damage, but by explosives installed in the buildings in advance. Controlled demolition theories make up a major component of 9/11 conspiracy theories. Early advocates such as physicist Steven E. Jones, architect Richard Gage, software engineer Jim Hoffman, and theologian David Ray Griffin, argued that the aircraft impacts and resulting fires could not have weakened the buildings sufficiently to initiate a catastrophic collapse, and that the buildings would not have collapsed completely, nor at the speeds that they did, without additional energy involved to weaken their structures.

The National Institute of Standards and Technology (NIST) and the magazine Popular Mechanics examined and rejected these theories. Specialists in structural mechanics and structural engineering accept the model of a fire-induced, gravity-driven collapse of the World Trade Center buildings, an explanation that does not involve the use of explosives. NIST "found no corroborating evidence for alternative hypotheses suggesting that the WTC towers were brought down by controlled demolition using explosives planted prior to Sept. 11, 2001."

In 2006, Jones suggested that thermite or super-thermite may have been used by government insiders with access to such materials and to the buildings themselves, to demolish the buildings. In April 2009, Jones, Danish Niels H. Harrit and seven other authors published a paper in The Open Chemical Physics Journal, causing the editor, Prof. Marie-Paule Pileni, to resign as she accused the publisher of printing it without her knowledge; this article was titled 'Active Thermitic Material Discovered in Dust from the 9/11 World Trade Center Catastrophe', and stated that they had found evidence of nano-thermite in samples of the dust that was produced during the collapse of the World Trade Center towers. NIST responded that there was no "clear chain of custody" to prove that the four samples of dust came from the WTC site. Jones invited NIST to conduct its own studies using its own known "chain of custody" dust, but NIST did not investigate.

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