Controlled demolition hypothesis for the collapse of the World Trade Center

The World Trade Center controlled demolition conspiracy theory is a conspiracy theory

Conspiracy theory

A conspiracy theory explains an event as being the result of an alleged plot by a covert group or organization or, more broadly, the idea that important political, social or economic events are the products of secret plots that are largely unknown to the general public.-Usage:The term "conspiracy...

which contends that the collapse of the World Trade Center

Collapse of the World Trade Center

The twin towers of the World Trade Center collapsed on September 11, 2001, as a result of al-Qaeda's September 11 attacks, in which terrorists affiliated with al-Qaeda hijacked four commercial passenger jet airliners, flying one into the North Tower and another into the South Tower...

was not caused by the airliner crash damage that occurred as part of the September 11, 2001 attacks, nor by resulting fire damage, but by explosives installed in the buildings in advance.

Early on, advocates such as physicist Steven E. Jones

Steven E. Jones

Steven Earl Jones is an American physicist. For most of his career, Jones was known mainly for his work on muon-catalyzed fusion. In the fall of 2006, amid controversy surrounding his work on the collapse of the World Trade Center , he was relieved of his teaching duties...

, architect Richard Gage, software engineer Jim Hoffman

Jim Hoffman

Jim Hoffman is a website engineer in Oakland, California, who created several web sites about the September 11, 2001 attacks that analyze and suggest alternative accounts for the events of that day, often described as 9/11 conspiracy theories. His primary website, , serves as an archive of...

, and theologian David Ray Griffin

David Ray Griffin

David Ray Griffin is a retired American professor of philosophy of religion and theology. Along with John B. Cobb, Jr., he founded the Center for Process Studies in 1973, a research center of Claremont School of Theology which seeks to promote the common good by means of the relational approach...

, argued that the aircraft impacts and resulting fires could not have weakened the buildings sufficiently to initiate a catastrophic collapse

Structural failure

Structural failure refers to loss of the load-carrying capacity of a component or member within a structure or of the structure itself. Structural failure is initiated when the material is stressed to its strength limit, thus causing fracture or excessive deformations...

, 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

National Institute of Standards and Technology

The National Institute of Standards and Technology , known between 1901 and 1988 as the National Bureau of Standards , is a measurement standards laboratory, otherwise known as a National Metrological Institute , which is a non-regulatory agency of the United States Department of Commerce...

(NIST) and the magazine Popular Mechanics
Popular Mechanics
Popular Mechanics is an American magazine first published January 11, 1902 by H. H. Windsor, and has been owned since 1958 by the Hearst Corporation...

examined and rejected these theories. Specialists in structural mechanics

Structural mechanics

Structural mechanics or Mechanics of structures is the computation of deformations, deflections, and internal forces or stresses within structures, either for design or for performance evaluation of existing structures. It is one subset of structural analysis...

and structural engineering

Structural engineering

Structural engineering is a field of engineering dealing with the analysis and design of structures that support or resist loads. Structural engineering is usually considered a specialty within civil engineering, but it can also be studied in its own right....

generally 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 did not test for explosive compound residue in steel samples, stating the potential for inconclusive results, and noting that similar compounds would have been present during construction of the towers.

In 2006, Jones suggested that thermite

Thermite

Thermite is a pyrotechnic composition of a metal powder and a metal oxide that produces an exothermic oxidation-reduction reaction known as a thermite reaction. If aluminium is the reducing agent it is called an aluminothermic reaction...

or super-thermite may have been used by government insiders with access to such materials and to the buildings themselves, to demolish the buildings. Later, Niels H. Harrit et al. 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.

In April 2009, Steven E. Jones, along with Niels Harrit and 7 other authors published a paper in The Open Chemical Physics Journal, titled, 'Active Thermitic Material Discovered in Dust from the 9/11 World Trade Center Catastrophe'.

NIST then said that there was no "clear chain of custody

Chain of custody

Chain of custody refers to the chronological documentation or paper trail, showing the seizure, custody, control, transfer, analysis, and disposition of evidence, physical or electronic...

" 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.

History

Questions related to the technical details of the collapse of the buildings of the World Trade Center have been debated for years, including rebuttals and ridicule. Controlled demolition

Building implosion

In the controlled demolition industry, building implosion is the strategic placing of explosive material and timing of its detonation so that a structure collapses on itself in a matter of seconds, minimizing the physical damage to its immediate surroundings...

conspiracy theories were first suggested in October 2001. Eric Hufschmid's book, Painful Questions: An Analysis of the September 11th Attack, in which the controlled demolition theory is explicitly advocated, was published in September 2002. David Ray Griffin

David Ray Griffin

and Steven E. Jones

Steven E. Jones

are the two most prominent advocates of the theory. Griffin's book The New Pearl Harbor
The New Pearl Harbor
The New Pearl Harbor: Disturbing Questions About the Bush Administration and 9/11 is a book written by David Ray Griffin, a retired professor of philosophy at the Claremont School of Theology. It draws analogies between the September 11, 2001, attacks and the attack on Pearl Harbor in 1941...

, published in 2004, has become a reference work for the 9/11 Truth movement

9/11 Truth Movement

9/11 Truth movement is a collective name for loosely affiliated organizations and individuals who question the accepted account of the September 11, 2001, attacks....

. In the same year, Griffin published the book The 9/11 Commission Report: Omissions and Distortions, in which he argues that flaws in the commission's report

9/11 Commission Report

The 9/11 Commission Report, formally named Final Report of the National Commission on Terrorist Attacks Upon the United States, is the official report of the events leading up to the September 11, 2001 attacks...

amounts to a cover-up by government officials and says that the Bush administration was complicit in the 9/11 attacks. Griffin theorized in a June 2010 article that those in the alleged false flag

False flag

False flag operations are covert operations designed to deceive the public in such a way that the operations appear as though they are being carried out by other entities. The name is derived from the military concept of flying false colors; that is flying the flag of a country other than one's own...

operation wanted the buildings to fall straight down. If they had toppled over, they would have destroyed dozens of other buildings and killed tens of thousands of people.

Steven E. Jones has been a leading academic voice of the proponents of demolition theories. In 2006, he published the paper "Why Indeed Did the WTC Buildings Completely Collapse?". Brigham Young University

Brigham Young University

Brigham Young University is a private university located in Provo, Utah. It is owned and operated by The Church of Jesus Christ of Latter-day Saints , and is the United States' largest religious university and third-largest private university.Approximately 98% of the university's 34,000 students...

responded to Jones' "increasingly speculative and accusatory" statements by placing him on paid leave, and thereby stripping him of two classes, in September 2006, pending a review of his statements and research. Six weeks later, Jones retired from the university. The structural engineering faculty at the university issued a statement which said that they "do not support the hypotheses of Professor Jones".

David Ray Griffin has questioned the "pancake collapse" theory suggested in the Building Performance Study produced by the Federal Emergency Management Agency

Federal Emergency Management Agency

The Federal Emergency Management Agency is an agency of the United States Department of Homeland Security, initially created by Presidential Reorganization Plan No. 1 of 1978 and implemented by two Executive Orders...

(FEMA). NIST's report on the collapse of the WTC towers rejected the theory in favor of the column failure theory. In its final report, NIST stated that it "found no corroborating evidence for alternative hypotheses suggesting that the WTC towers were brought down by controlled demolition using explosives planted prior to September 11, 2001" and posted a FAQ

FAQ

Frequently asked questions are listed questions and answers, all supposed to be commonly asked in some context, and pertaining to a particular topic. "FAQ" is usually pronounced as an initialism rather than an acronym, but an acronym form does exist. Since the acronym FAQ originated in textual...

about related issues on its website in August 2006. The major elements of the theory have been rebutted by mainstream engineering scholarship, where its proponents are considered "outsiders". The magazine Popular Mechanics
Popular Mechanics
Popular Mechanics is an American magazine first published January 11, 1902 by H. H. Windsor, and has been owned since 1958 by the Hearst Corporation...

challenged the theories in the special report "Debunking the 9/11 Myths".

Articles, letters and comments by controlled demolition advocates have been published in scientific and engineering journals. In April 2008, a letter titled "Fourteen Points of Agreement with Official Government Reports on the World Trade Center Destruction," was published by Steven E. Jones

Steven E. Jones

, Frank Legge, Kevin Ryan, Anthony Szamboti and James Gourley in The Open Civil Engineering Journal. A few months later, in July 2008, an article titled "Environmental anomalies at the World Trade Center: evidence for energetic materials," was published by Ryan, Gourley and Jones in the Environmentalist. Later that same year, in October 2008, a comment by James R. Gourley, describing what he considers fundamental errors in a Bažant and Verdure paper, was published in the Journal of Engineering Mechanics. And in April 2009, Danish chemist Niels H. Harrit, of the University of Copenhagen, and eight other authors published a paper in The Open Chemical Physics Journal, titled, "Active Thermitic Material Discovered in Dust from the 9/11 World Trade Center Catastrophe." The paper concludes that chips consisting of unreacted and partially reacted super-thermite, or nano-thermite, appear to be present in samples of the dust.

Internet websites and videos have contributed to the growth of the movement of individuals supporting the theory that planted explosives destroyed the World Trade Center. The website of Architects and Engineers for 9/11 Truth cites the membership of over 1,500 architects and engineers. The controlled demolition theory often includes allegations that U.S. government insiders planned and / or participated in the destruction of the WTC in order to justify the invasion of Iraq and Afghanistan

War on Terrorism

The War on Terror is a term commonly applied to an international military campaign led by the United States and the United Kingdom with the support of other North Atlantic Treaty Organisation as well as non-NATO countries...

. The theory features prominently in popular entertainment type movies, such as Loose Change, as well as more documentary type films, such as 9/11: Blueprint for Truth, by San Francisco-area architect Richard Gage, which are based mainly on presentations of scientific and engineering evidence for the controlled demolition theory.

While mainstream press has a significant history of derogatory labels, descriptions and interpretations of demolition theory advocates (i.e., in 2006, the magazine New York

New York (magazine)

New York is a weekly magazine principally concerned with the life, culture, politics, and style of New York City. Founded by Milton Glaser and Clay Felker in 1968 as a competitor to The New Yorker, it was brasher and less polite than that magazine, and established itself as a cradle of New...

reported that a "new generation of conspiracy theorists is at work on a secret history of New York’s most terrible day."), the theory has been supported by a number of popular actors, musicians and politicians, including Charlie Sheen, Willie Nelson, former Governor of Minnesota Jesse Ventura, talkshow host Rosie O'Donnell

Rosie O'Donnell

Roseann "Rosie" O'Donnell is an American stand-up comedian, actress, author and television personality. She has also been a magazine editor and continues to be a celebrity blogger, LGBT rights activist, television producer and collaborative partner in the LGBT family vacation company R Family...

, and actors Ed Asner

Ed Asner

Edward Asner , commonly known as Ed Asner, is an American film, television, stage, and voice actor and former president of the Screen Actors Guild, primarily known for his Emmy Award-winning role as Lou Grant on both The Mary Tyler Moore Show and its spin-off series, Lou Grant...

and Daniel Sunjata

Daniel Sunjata

Daniel Sunjata is an American actor who performs in film, television and in the theater.-Career:...

Main towers

On September 11, the North Tower (1 WTC) was hit by American Airlines Flight 11

American Airlines Flight 11

American Airlines Flight 11 was American Airlines' daily scheduled morning transcontinental flight from Logan International Airport, in Boston, Massachusetts, to Los Angeles International Airport, in Los Angeles, California...

and the South Tower (2 WTC) was hit by United Airlines Flight 175

United Airlines Flight 175

United Airlines Flight 175 was United Airlines' daily scheduled morning transcontinental flight, from Logan International Airport in Boston, Massachusetts, to Los Angeles International Airport in Los Angeles, California...

, both Boeing 767

Boeing 767

The Boeing 767 is a mid-size, wide-body twin-engine jet airliner built by Boeing Commercial Airplanes. It was the manufacturer's first wide-body twinjet and its first airliner with a two-crew glass cockpit. The aircraft features two turbofan engines, a supercritical wing, and a conventional tail...

aircraft. The South Tower collapsed 56 minutes after the impact, and the North Tower collapsed 102 minutes after. An investigation by NIST concluded that the collapse was caused by a combination of damage to support columns and fire insulation from the aircraft impacts and the weakening of columns and floors by jet fuel

Jet fuel

Jet fuel is a type of aviation fuel designed for use in aircraft powered by gas-turbine engines. It is clear to straw-colored in appearance. The most commonly used fuels for commercial aviation are Jet A and Jet A-1 which are produced to a standardized international specification...

ignited fires. NIST also found "no corroborating evidence for alternative hypotheses suggesting that the WTC towers were brought down by controlled demolition using explosives planted prior to September 11, 2001".

Physicist Steven E. Jones

Steven E. Jones

, among others, points to many descriptions by individuals working on the WTC rubble pile suggesting the presence of molten steel in the pile and a stream of molten metal that poured out of the South Tower before it collapsed as evidence of temperatures beyond those produced by the fire. Jones has argued that the molten metal may have been elemental iron

Iron

Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

, a product of a thermite reaction. Jones and other researchers analyzed samples of dust from the World Trade Center buildings and reported their findings for evidence of nano-thermite in the dust. Jones informed NIST of his findings and NIST responded that there was no "clear chain of custody" proving that the dust indeed came from the WTC site. Jones invited NIST to conduct its own studies with dust under custody of NIST itself, but NIST has not done so.

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 the South Tower was molten aluminum from the plane, which would have melted at lower temperatures than steel. NIST 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. A test performed by the Energetic Materials Research and Testing Center

Energetic Materials Research and Testing Center

The Energetic Materials Research and Training Center is a research division of New Mexico Tech, which performs testing of high explosives, bombs, and other munitions, as well as the means to deliver such munitions. It also offers courses for emergency responders in bomb response. EMRTC's offices...

showed that conventional thermite was unable to melt a column much smaller than those used in the World Trade Center. Jones and others have responded that they do not believe that thermite was used, but rather a form of thermite called nano-thermite, a nanoenergetic material which developed for military use, propellants, explosives, or pyrotechnics. Historically, explosive applications for traditional thermites have been limited by their relatively slow energy release rates. But because nano-thermites are created from reactant particles with proximities approaching the atomic scale, energy release rates are far improved.

The NIST report provides an analysis of the structural response of the building only up to the point where collapse begins, and asserts that the enormous kinetic energy

Kinetic energy

The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...

transferred by the falling part of the building makes progressive collapse

Progressive collapse

A building undergoes progressive collapse when a primary structural element fails, resulting in the failure of adjoining structural elements, which in turn causes further structural failure, similar to a house of cards....

inevitable once an initial collapse occurs. A paper by Zdeněk Bažant

Zdenek Bažant

Zdeněk Pavel Bažant is McCormick School Professor and Walter P. Murphy Professor of Civil Engineering and Materials Science in the Department of Civil and Environmental Engineering at Northwestern University's Robert R...

indicates that once collapse began, the kinetic energy imparted by a falling upper section onto the floor below was an order of magnitude greater than that which the lower section could support.

Engineers who have investigated the collapses generally disagree that controlled demolition is required to understand the structural response of the buildings. While the top of one of the towers did tilt significantly, it could not ultimately have fallen into the street, they argue, because any such tilting would place sufficient stress on the lower story (acting as a pivot) that it would collapse long before the top had sufficiently shifted its center of gravity. Indeed, they argue, there is very little difference between progressive collapse with or without explosives in terms of the resistance that the structures could provide after collapse began. Controlled demolition of a building to code

Building code

A building code, or building control, is a set of rules that specify the minimum acceptable level of safety for constructed objects such as buildings and nonbuilding structures. The main purpose of building codes are to protect public health, safety and general welfare as they relate to the...

requires weeks of preparation, including laying large quantities of explosive and cutting through beams, which would have rendered the building highly dangerous and which would have to be done without attracting the attention of the thousands of people who worked in the building. Controlled demolition is traditionally done from the bottom of buildings rather than the top, although there are exceptions depending on structural design. There is little dispute that the collapse started high up at the point where the aircraft struck. Furthermore any explosives would have to withstand the impact of the airliners.

Members of the group Scholars for 9/11 Truth have collected eyewitness accounts of flashes and loud explosions immediately before the fall. Eyewitnesses have repeatedly reported of explosions happening before the collapse of the WTC towers, and the organization "International Center for 9/11 Studies" has published videos obtained from NIST, together with indications about when such explosions could be heard. There are many types of loud sharp noises that are not caused by explosives, and seismographic

Seismology

Seismology is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies. The field also includes studies of earthquake effects, such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, oceanic,...

records of the collapse do not show evidence of explosions. Physicist Steven E. Jones

Steven E. Jones

and others have argued that horizontal puffs of smoke seen during the collapse of the towers would indicate that the towers had been brought down by controlled explosions.• the 9/11 Truth Movement, as many conspiracy believers refer to their passion NIST attributes these puffs to air pressure, created by the decreasing volume of the falling building above, traveling down elevator shafts and exiting some open elevator shaft doors on lower levels).

In September 2011 Iranian President Ahmadinejad an engineer, said that it would have been impossible for two jetliners to bring down the towers simply by hitting them and that some kind of planned explosion must have taken place.

7 World Trade Center

Proponents of World Trade Center controlled demolition theories allege that 7 World Trade Center

7 World Trade Center

7 World Trade Center is a building in New York City located across from the World Trade Center site in Lower Manhattan. It is the second building to bear that name and address in that location. The original structure was completed in 1987 and was destroyed in the September 11 attacks...

-- a 47-story skyscraper that stood across Vesey Street north of the main part of the World Trade Center site

World Trade Center site

The World Trade Center site , also known as "Ground Zero" after the September 11 attacks, sits on in Lower Manhattan in New York City...

-- was intentionally destroyed with explosives. Unlike the Twin Towers, 7 World Trade Center was not hit by a plane, although it was hit by debris from the Twin Towers and was damaged by fires which burned for seven hours, until it collapsed totally at about 5:20 p.m. on the evening of September 11 (a new building has been erected on the site of the old and opened in May 2006). Several videos of the collapse event exist in the public domain, thus enabling comparative analysis from different angles of perspective. Proponents typically say the collapse of 7 World Trade Center was not mentioned in the 9/11 Commission Report

9/11 Commission Report

and that the federal body charged with investigating the event, NIST, required seven years to conduct its investigation and issue a report.

In November 2010, Fox News reporter Geraldo Rivera

Geraldo Rivera

Geraldo Rivera is an American attorney, journalist, author, reporter, and former talk show host...

hosted members of a television ad campaign called "BuildingWhat?", a series of commercials in which 9/11 family members ask questions about 7 World Trade Center

7 World Trade Center

and call for an investigation into its collapse. Rivera called the television ads "not so easy to dismiss as those demonstrators were," and stated that, "If explosives were involved, that would mean the most obnoxious protesters in recent years ... were right." Days later, Rivera appeared on the program Freedom Watch

Freedom Watch

Freedom Watch is a television show hosted by Judge Andrew Napolitano. It was created in February 2009 as an online show and originally webcast once a week. In September 2009, the show began webcasting 3 or 4 times a week...

with legal analyst Judge Andrew Napolitano

Andrew Napolitano

Andrew Paolo Napolitano is a former New Jersey Superior Court Judge and now a political and legal analyst for Fox News Channel. Napolitano started on the channel in 1998, and currently serves as the network's senior judicial analyst, commenting on legal news and trials...

on the Fox Business Network

Fox Business Network

Fox Business Network is an American cable news and satellite news television channel that began broadcasting on October 15, 2007. It is owned by the Fox Entertainment Group, part of Rupert Murdoch's News Corporation...

to discuss the BuildingWhat? TV ad campaign. Napolitano stated, "It's hard for me to believe that [7 World Trade Center] came down by itself. I was gratified to see Geraldo Rivera investigating it." FOX News was heavily criticized for airing programs questioning the basis for the collapse of 7 World Trade Center by the internet media groups Media Matters

Media Matters

Media Matters can refer to:* Media Matters for America, progressive media watchdog group founded by author David Brock* The radio program Media Matters hosted by communications professor Robert W. McChesney...

and Newsbusters.

Some proponents of World Trade Center controlled demolition theories suggest that 7 WTC was demolished because it may have served as an operational center for the demolition of the Twin Towers, while others suggest that government insiders may have wanted to destroy key files held in the building pertaining to corporate fraud. The WTC buildings housed dozens of federal, state and local government agencies. According to a statement reported by the BBC

BBC

The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...

, Loose Change

Loose Change

Loose change or Loose Change may refer to:* An English expression that refers to small amounts of coins of low value* Loose Change , films about the September 11, 2001 attacks* Loose Change , a 1977 non-fiction book by Sara Davidson...

film producer Dylan Avery

Dylan Avery

Dylan Avery is the writer, director, and editor of the Loose Change films. He is from Oneonta, New York, and currently lives in San Diego, California. After being denied admission twice by Purchase College's film school, Avery planned to make a fictional thriller about a group of friends who...

thinks the destruction of the building was suspicious because it housed some unusual tenants, including a clandestine CIA office on the 25th floor, an outpost of the U.S. Secret Service, the Securities and Exchange Commission, and New York City's emergency command center. The former chief counter-terrorism adviser to the President, Richard Clarke

Richard A. Clarke

Richard Alan Clarke was a U.S. government employee for 30 years, 1973–2003. He worked for the State Department during the presidency of Ronald Reagan. In 1992, President George H.W. Bush appointed him to chair the Counter-terrorism Security Group and to a seat on the United States National...

, does not think that 7 WTC is mysterious, and said that anyone could have rented floor space in the building.

No steel frame

Steel frame

Steel frame usually refers to a building technique with a "skeleton frame" of vertical steel columns and horizontal -beams, constructed in a rectangular grid to support the floors, roof and walls of a building which are all attached to the frame...

high rise had ever before collapsed because of a fire, although there had been previous cases of collapses or partial collapses of smaller steel buildings due to fire. BBC News reported the collapse of 7 WTC twenty minutes before it actually fell. The BBC has stated that many news sources were reporting the imminent collapse of 7 WTC on the day of the attacks. Jane Standley, the reporter who announced the collapse prematurely, called it a "very small and very honest mistake" caused by her thinking on her feet after being confronted with a report she had no way of checking.

In the PBS documentary America Rebuilds, which aired in September 2002, Larry Silverstein

Larry Silverstein

Larry A. Silverstein is an American businessman, and real estate investor and developer in New York City.Silverstein was born in Brooklyn, and became involved in real estate, together with his father, establishing Silverstein Properties...

, the owner of 7 WTC and leaseholder and insurance policy holder for the remainder of the WTC complex, recalled a discussion with the fire department in which doubts about containing the fires were expressed. Silverstein recalled saying, "We've had such terrible loss of life, maybe the smartest thing to do is pull it". "They made that decision to pull", he recalled, "and we watched the building collapse." Silverstein issued a statement that it was the firefighting team, not the building, that was to be pulled.

Evidence

In 2009 a paper by nine scientists described their discovery and chemical and physical analysis of small "red/gray chips in all the samples we have studied of the dust produced by the destruction of the World Trade Center," which were collected at four separate sites. Such chips "have apparently not been discussed in previously published reports. It is worth emphasizing that one sample was collected about ten minutes after the collapse of the second Tower, so it cannot possibly have been contaminated by clean-up operations." "[W]e conclude that the red layer of the red/gray chips we have discovered in the WTC dust is active, unreacted thermitic material, incorporating nanotechnology, and is a highly energetic pyrotechnic or explosive material." Others have analyzed 9/11 dust samples and reached similar but more extensive conclusions.

Earlier, in 2006, Professor Steven E. Jones

Steven E. Jones

, of BYU, said debris from 7 WTC contained sulfur

Sulfur

Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

ic compounds, suggesting that thermate

Thermate

Thermate is a variation of thermite and is an incendiary pyrotechnic composition that can generate short bursts of very high temperatures focused on a small area for a short period of time. It is used primarily in incendiary grenades....

, a mixture of thermitic materials and sulfur, was present. Presence of sulfur is of interest because when used in a thermite compound it reduces the melting point of steel. Professor Richard Sisson of Worcester Polytechnic Institute

Worcester Polytechnic Institute

Worcester Polytechnic Institute is a private university located in Worcester, Massachusetts, in the United States.Founded in 1865 in Worcester, WPI was one of the United States' first engineering and technology universities...

said that he believed the sulfur came from gypsum

Gypsum

Gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is found in alabaster, a decorative stone used in Ancient Egypt. It is the second softest mineral on the Mohs Hardness Scale...

in the wallboards. The NIST's question and answer page for the 7 WTC investigation also mentions the presence of sulfur in the gypsum wallboard, and states that an analysis of the steel for thermite or thermate would therefore not necessarily be conclusive. However, NIST simply never checked for the presence of thermite or thermate (the thermite with sulfur added). Also, extremely high temperatures are necessary to disassociate the sulfur and the calcium that are contained in gypsum board. "[A]nd if you've got those temperatures you've got the temperatures to melt the steel. ... this is impossible to achieve in a normal office fire, even a jet fuel-fed office fire. This is one of the reasons they use wallboard; it's not going to disassociate in normal office fires and attack steel members that are part of steel structures."

NIST Report

In 2002, the National Institute of Standards and Technology (NIST) began a general investigation into the collapse of the World Trade Center but soon made a decision to focus first on the collapse of the Twin Towers. A draft version of its final report on the collapse of 7 WTC was released in August 2008. The agency has blamed the slowness of this investigation on the complexity of the computer model it used, which simulated the collapse from the moment it begins all the way to the ground; and NIST says the time taken on the investigation into 7 WTC is comparable to the time taken to investigate an aircraft crash. The agency also says another 80 boxes of documents related to 7 WTC were found and had to be analyzed. These delays fueled suspicion the agency was struggling to come up with a plausible conclusion.

NIST released its final report on the collapse of 7 World Trade Center on November 20, 2008. Investigators used videos, photographs and building design documents to come to their conclusions. The investigation could not include physical evidence as the materials from the building lacked characteristics allowing them to be positively identified and were therefore disposed of prior to the initiation of the investigation. The report concluded that the building's collapse was due to the effects of the fires which burned for almost seven hours. The fatal blow to the building came when the 13th floor collapsed, weakening a critical steel support column that led to catastrophic failure, and extreme heat caused some steel beams to lose strength, causing further failures throughout the buildings until the entire structure succumbed. Also cited as a factor was the collapse of the nearby towers, which broke the city water main, leaving the sprinkler system in the bottom half of the building without water.

NIST considered the possibility that 7 WTC was brought down with explosives and concluded that a blast event did not occur, that the "use of thermite [...] to sever columns in 7 WTC on 9/11/01 was unlikely". The investigation cited as evidence the claim that no blast was audible on recordings of the collapse and that no blast was reported by witnesses, stating that it would have been audible at a level of 130-140 decibels at a distance of half a mile. Demolition proponents say eyewitnesses repeatedly reported explosions happening before the collapse of the towers, and have published videos obtained from NIST, together with indications about when such explosions could be heard in support of the sounds of explosions before collapse.

NIST also concluded that it is unlikely that the quantities of thermite needed could have been carried into the building undetected. Demolition advocates have responded that they do not claim that thermite was used, but rather nano-thermite, far more powerful than thermite, was used. Finally, the theory that fires from the large amount of diesel fuel stored in the building caused the collapse was also investigated and ruled out.

Reactions

The structural engineering community rejects the controlled-demolition conspiracy theory. Its consensus is that the collapse of the World Trade Center buildings was a fire-induced, gravity-driven collapse, an explanation that does not involve the use of explosives.

The American Society of Civil Engineers

American Society of Civil Engineers

The American Society of Civil Engineers is a professional body founded in 1852 to represent members of the civil engineering profession worldwide. It is the oldest national engineering society in the United States. ASCE's vision is to have engineers positioned as global leaders who strive toward...

Structural Engineering Institute issued a statement calling for further discussion of NIST's recommendations, and Britain's Institution of Structural Engineers

Institution of Structural Engineers

The Institution of Structural Engineers is a professional body for structural engineering based in the United Kingdom. It has 27,000 members in 105 countries. The Institution provides professional accreditation for structural engineers...

published a statement in May 2002 welcoming the FEMA report, noting that the report expressed similar views to those held by its group of professionals.

Following the publication of Jones' paper "Why Indeed Did the WTC Buildings Completely Collapse?" Brigham Young University

Brigham Young University

responded to Jones' "increasingly speculative and accusatory" statements by placing him on paid leave, and thereby stripping him of two classes, in September 2006, pending a review of his statements and research. Six weeks later, Jones retired from the university. The structural engineering faculty at the university issued a statement which said that they "do not support the hypotheses of Professor Jones". On September 22, 2005, Jones gave a seminar on his hypotheses to a group of his colleagues from the Department of Physics and Astronomy at BYU. According to Jones, all but one of his colleagues agreed after the seminar that an investigation was in order and the lone dissenter came to agreement with Jones' suggestions the next day.

Northwestern University

Northwestern University

Northwestern University is a private research university in Evanston and Chicago, Illinois, USA. Northwestern has eleven undergraduate, graduate, and professional schools offering 124 undergraduate degrees and 145 graduate and professional degrees....

Professor of Civil Engineering

Civil engineering

Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including works like roads, bridges, canals, dams, and buildings...

Zdeněk Bažant, who was the first to offer a published peer-reviewed theory of the collapses, wrote "a few outsiders claiming a conspiracy with planted explosives" as an exception. Bažant and Verdure trace such "strange ideas" to a "mistaken impression" that safety margins in design would make the collapses impossible. One of the effects of a more detailed modeling of the progressive collapse, they say, could be to "dispel the myth of planted explosives". Indeed, Bažant and Verdure have proposed examining data from controlled demolitions in order to better model the progressive collapse of the towers, suggesting that progressive collapse and controlled demolition are not two separate modes of failure (as the controlled-demolition conspiracy theory assumes).

Thomas Eagar, a professor of materials science and engineering at the Massachusetts Institute of Technology

Massachusetts Institute of Technology

The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...

, also dismissed the controlled-demolition conspiracy theory. Eagar remarked, "These people (in the 9/11 truth movement) use the 'reverse scientific method

Scientific method

Scientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering empirical and measurable evidence subject to specific principles of...

.' They determine what happened, throw out all the data that doesn't fit their conclusion, and then hail their findings as the only possible conclusion."

Preparing a building for a controlled demolition takes considerable time and effort. The tower walls would have had to be opened on dozens of floors. Thousands of pounds of explosives, fuses and ignition mechanisms would need to be sneaked past security and placed in the towers without the tens of thousands of people working in the World Trade Center noticing. Referring to a conversation with Stuart Vyse, a professor of psychology, an article in the Hartford Advocate asks, "How many hundreds of people would you need to acquire the explosives, plant them in the buildings, arrange for the airplanes to crash [...] and, perhaps most implausibly of all, never breathe a single word of this conspiracy?"

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." Upon presentation of the NIST's detailed report on the failure of Bldg. 7, Richard Gage, leader of the group Architects & Engineers for 9/11 Truth
Architects & Engineers for 9/11 Truth
Architects & Engineers for 9/11 Truth is an American non-profit organization of architects, engineers, and demolition experts who dispute the results of official investigations into the September 11 attacks, including the 9/11 Commission Report...

said, "How much longer do we have to endure the coverup of how Building 7 was destroyed?" in which Dr. S. Shyam Sunder, the lead NIST investigator said he could not explain why the skepticism would not die. “I am really not a psychologist,” he said. “Our job was to come up with the best science.”
James Quintiere, professor of fire protection engineering

Fire protection engineering

Fire Protection Engineering is the application of science and engineering principles to protect people and their environments from the destructive effects of fire and smoke....

at the University of Maryland

University of Maryland, College Park

The University of Maryland, College Park is a top-ranked public research university located in the city of College Park in Prince George's County, Maryland, just outside Washington, D.C...

, 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," though he adds that NIST wasted time employing outside experts to consider it.

External links

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