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The National Institute of Standards and Technology (NIST) issues a progress report on its investigation into the World Trade Center collapses. Since 2002, NIST has been investigating the collapses of the Twin Towers and WTC Building 7 (see August 21, 2002). The progress report includes its “working hypothesis” for the collapse of WTC 7. This was a 47-story building, located about 350 feet from the north side of WTC 1, which collapsed completely at around 5:20 in the afternoon of 9/11. The report claims that “fire appears to have played a key role” in the collapse, though it points out, “No fire was observed or reported in the afternoon on floors 1-5, 10, or above Floor 13.” It also says, “there may have been some physical damage on the south side of the building.” NIST summarizes its working hypothesis of the WTC 7 collapse as follows:
bullet “An initial local failure at the lower floors (below Floor 13) of the building due to fire and/or debris induced structural damage of a critical column (the initiating event), which supported a large span floor bay with an area of about 2,000 square feet.”
bullet “Vertical progression of the initial local failure up to the east penthouse, as large floor bays were unable to redistribute the loads, bringing down the interior structure below the east penthouse.”
bullet “Horizontal progression of the failure across the lower floors… triggered by damage due to the vertical failure, resulting in the disproportionate collapse of the entire structure.”
NIST claims this hypothesis “is consistent with all evidence currently held by NIST, including photographs and videos, eyewitness accounts and emergency communication records,” but says it “will be revised and updated as results of ongoing, more comprehensive analyses become available.” [National Institute of Standards and Technology, 6/2004, pp. L1, L3, L17, L34, L38, L51-L52; National Institute of Standards and Technology, 6/18/2004] NIST will release its final reports on the collapses of the Twin Towers in October 2005 (see October 26, 2005). As of mid-2007, it has yet to release a final report on the collapse of WTC 7. In early 2006, Dr. S. Shyam Sunder, who is the lead investigator for NIST’s WTC investigation, will admit, “truthfully, I don’t really know” what caused WTC 7 to collapse. He will add, “We’ve had trouble getting a handle on building no. 7” (see March 20, 2006). [New York Magazine, 3/20/2006] An earlier report on the WTC collapses, released by the Federal Emergency Management Agency (FEMA) in May 2002, had been inconclusive on what caused WTC 7 to collapse, and stated that “Further research, investigation, and analyses” were necessary (see May 1, 2002). [Federal Emergency Management Agency, 5/1/2002, pp. 5-31]

Entity Tags: World Trade Center, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Shyam Sunder.Shyam Sunder. [Source: NIST]The National Institute of Standards and Technology (NIST) releases nearly 500 pages of documents, detailing the latest findings of its investigation of the WTC collapses on 9/11. These include its hypotheses for the collapse sequences of each of the Twin Towers; details of their analysis of interviews with nearly 1,200 building occupants, emergency responders, and victims’ relatives; and information from their analysis of the emergency response and evacuation procedures. Their investigation into the collapses is based upon an analysis of thousands of photos and videos, examination of many of the elements used to construct the towers, and computer-enhanced modeling of the plane impacts and the spreading of the fires. Their hypothesis is that the towers collapsed ultimately due to the fires they suffered: As the fires burned, the buildings’ steel core columns buckled and shortened. This shifted more load to the buildings’ perimeter columns, which were already affected by the heat of the fires, and caused them to give way under the increased stress. Investigators have conducted a test with a reconstructed section of the WTC floor, and found that the original fireproofing was sufficient to meet the New York City building code. They say that had a typical office fire occurred in the towers, without the structural damage and the loss of some fireproofing caused by the plane impacts, it is likely the buildings would have remained standing. Lead investigator Dr. Shyam Sunder says, “The buildings performed as they should have in the airplane impact and extreme fires to which they were subjected. There is nothing there that stands out as abnormal.” NIST’s theories of why the WTC buildings collapsed conflict with an earlier investigation by FEMA, which claimed the collapse of the North Tower had begun in its core, rather than its perimeter columns (see May 1, 2002). [National Institute of Standards and Technology, 10/19/2004; New York Times, 10/20/2004]

Entity Tags: Shyam Sunder, National Institute of Standards and Technology, World Trade Center

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

President Bush nominates former New York City Police Commissioner Bernard Kerik to head the Department of Homeland Security, replacing outgoing DHS head Tom Ridge. Kerik is a close friend and political ally of former New York Mayor Rudolph Giuliani, who pushed Kerik for the position. Kerik also actively campaigned for Bush in the recent presidential campaign. “Bernie Kerik is one of the most accomplished and effective leaders of law enforcement in America,” Bush says. “In every position, he has demonstrated a deep commitment to justice, a heart for the innocent, and a record of great success. I’m grateful he’s agreed to bring his lifetime of security experience and skill to one of the most important positions in the American government.” Kerik recently returned from a stint in Iraq, where he trained Iraqi police officials (see May 2003 - July 2003). Kerik was also in charge of New York City police activities during the 9/11 attacks (see (After 10:28 a.m.-12:00 pm.) September 11, 2001). Kerik says: “I know what is at stake. On September 11, 2001, I witnessed firsthand the very worst of humanity and the very best.… I saw hatred claim the lives of 2,400 innocent people, and I saw the bravest men and women I will ever know rescue more than 20,000 others.” Bush says of Kerik: “He was there when the Twin Towers collapsed—he knew the faces of the rescuers who rushed toward danger, he attended the funerals for the officers who didn’t come back. Bernie Kerik understands the duties that came to America on September 11. The resolve he felt that morning will guide him every day on his job and every first responder defending our homeland will have a faithful ally in Bernie Kerik.” Congressional Republicans laud Kerik’s nomination. Senator Susan Collins (R-ME), the chair of the Senate Governmental Affairs Committee, which oversees DHS, calls Kerik a “strong candidate” for the post. “He knows first hand the challenges this country faces in guarding against terrorist attacks,” Collins says. House Homeland Security Committee Chairman Christopher Cox (R-CA) calls Kerik “the perfect choice for the job,” and goes on to say: “There is no doubt that Bernie is a strong, no-nonsense manager who is intimately familiar with the homeland security mission. The new standing Committee on Homeland Security will work closely with him to build on the strong foundations laid by Tom Ridge to secure America against terrorism.” Some Democrats, including Senator Charles Schumer (D-NY), also praise Kerik’s nomination. “Coming from New York, Bernie Kerik knows the great needs and challenges this country faces in homeland security,” Schumer says. “He has a strong law enforcement background and I believe will do an excellent job in fighting for the resources and focus that homeland security needs and deserves in our post-9/11 world.” Kerik’s biggest drawback as the choice to head DHS may be his lack of experience in managing a federal bureaucracy, some observers say. Former New York Police Commissioner Howard Safire says of Kerik: “Bernie is a very good operational person, he knows how to run the operation. What he needs to learn and what he’s going to need help with is the Washington bureaucracy.” DHS is an umbrella department overseeing and managing 22 separate federal agencies and some 200,000 employees and contract workers. [New York Times, 12/2/2004; Fox News, 12/3/2004; McClellan, 2008, pp. 245-246] “People here are waiting to find out who this guy is and what changes he’ll bring,” says an anonymous Homeland Security senior official. “He’s really an unknown factor here in Washington.” [New York Times, 12/4/2004] In 2008, Scott McClellan, the current White House press secretary, will describe DHS as “still in its infancy and still struggling to define its identity,” and will call it a “vast, unwieldy agglomeration of dozens of formerly independent agencies, now bundled together under one name, and with a new focus (physical threats to the American ‘homeland’) that sometimes contradicted the old mandates. Homeland Security was hampered by bureaucratic infighting, incredibly complex coordination challenges, and slumping employee morale.” [McClellan, 2008, pp. 245-246] Less than two weeks later, Kerik will withdraw his name from consideration, ostensibly over a problem with an illegal immigrant he hired to babysit his children (see December 13, 2004), though some believe his withdrawal is spurred by the media’s interest in his business dealings (see December 9-10, 2004).

Entity Tags: George W. Bush, Bernard Kerik, Christopher Cox, Charles Schumer, US Department of Homeland Security, Susan Collins, Rudolph (“Rudy”) Giuliani, Scott McClellan, Tom Ridge, Howard Safire

Timeline Tags: Civil Liberties

The National Institute of Standards and Technology (NIST), which is conducting an investigation into the WTC collapses on 9/11, releases three new reports. Investigators say that the Twin Towers would probably have remained standing if the fireproofing material that surrounded the buildings’ structural steel had not been stripped away when the planes hit. Their report states that “[t]he jet fuel, which ignited the fires, was mostly consumed within the first few minutes after impact. The fires that burned for almost the entire time that the buildings remained standing were due mainly to burning building contents and, to a lesser extent, aircraft contents, not jet fuel.” However, they claim, without the loss of fireproofing during the planes’ impacts, the heat from the fires would have been insufficient to cause the buildings to collapse. They say that although the architects had in 1964 tested the impact of a Boeing 707 airplane crashing into the 80th floor of one of the towers, they never envisioned the intense fires that ensued. NIST also reports that the time taken by survivors from the North Tower to descend a flight of stairs was about double the slowest evacuation speed estimated in a standard fire engineering text. They state: “approximately 87 percent of the WTC tower occupants, including more than 99 percent below the floors of impact, were able to evacuate successfully.” However, they say, if each tower had been full when they were hit, as many as 14,000 people could have died. [National Institute of Standards and Technology, 4/5/2005; Associated Press, 4/5/2005; New York Times, 4/5/2005; Associated Press, 4/6/2005]

Entity Tags: World Trade Center, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Both towers of the World Trade Center tilted to one side before beginning to fall on 9/11 (see 9:59 a.m. September 11, 2001 and 10:28 a.m. September 11, 2001). The National Institute of Standards and Technology, which investigated the collapses (see August 21, 2002), states that the South Tower, which was hit on its south side, tilted about 7-8 degrees to the east and 3-4 degrees to the south, and the North Tower, which was hit on its north side, tilted about 8 degrees to the south, before starting to fall. [National Institute of Standards and Technology, 9/2005, pp. 300, 308 pdf file] However, these findings are criticized by Canadian scientist Frank Greening. After examining photo and video evidence, Greening says that the South Tower tilted by no more than two degrees and the North Tower by no more than three degrees before collapse initiation. Greening also says that the tilt angles NIST gives cannot correspond to the downward movement of the towers’ walls NIST claims before they started to fall, and points out that the tilt angles NIST uses are inconsistent throughout its reports. Though Greening agrees with NIST that the towers were destroyed by the plane impacts and fire damage, he concludes that its computer model is “highly inaccurate and therefore of no value in explaining the demise of the Twin Towers.” [Greening, 11/2005 pdf file] Greening is a leading figure in the post-9/11 dispute over why the WTC collapsed and publishes a series of papers dealing with various aspects of the Twin Towers’ collapse. For example, a CBC documentary uses Greening for analysis of the WTC’s fall. [Canadian Broadcasting Corporation, 8/25/2005]

Entity Tags: World Trade Center, Frank Greening, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

National Institute of Standards and Technology (NIST) releases a 12-page appendix to its final reports on the WTC collapses (see October 26, 2005) detailing tests it conducted on samples of the type of fireproofing used in the WTC. An earlier NIST report had concluded that loss of fireproofing was a major factor in the collapses (see April 5, 2005). The appendix was not included in earlier drafts of the report (see June 23, 2005) [National Institute of Standards and Technology, 6/23/2005 pdf file; National Institute of Standards & Technology, 9/2005, pp. 263-274 pdf file; National Institute of Standards and Technology, 9/2005, pp. 149] NIST conducted a series of fifteen tests. In the tests projectiles were fired at fireproofing mounted on 12 inch x 12 inch plates, and steel bars with a one inch diameter. The fireproofing used in the tests was Blazeshield DC/F, one of the two grades of fireproofing used on the impact floors. In thirteen of the tests the projectiles were buckshot, which was fired at the steel samples from a modified shotgun at a distance of 29.5 ft. The other two tests used steel bolts and hexagon nuts, fired with less velocity and at closer range. According to NIST, “The test results support the assumption that, within the debris field created by the aircraft impact into WTC 1 and WTC 2, the SFRM [i.e., fireproofing] used for thermal insulation of structural members was damaged and dislodged.” [National Institute of Standards & Technology, 9/2005, pp. 83, 263-274 pdf file]

Entity Tags: National Institute of Standards and Technology, World Trade Center

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

A poll released by Zogby International shows widespread skepticism towards the official 9/11 story. The nationwide telephone survey of 1,200 adults finds that 42 percent of respondents agreed that “the US government and its 9/11 Commission concealed or refused to investigate critical evidence that contradicts their official explanation of the September 11th attacks,” and that “there has been a cover-up.” Ten percent of respondents said they were unsure, while less than half said the government and 9/11 Commission were not covering up. Forty-five percent of respondents felt the 9/11 attacks should be reinvestigated. Forty-four percent believed that President Bush exploited the attacks to justify the 2003 invasion of Iraq. The survey also found that 43 percent of respondents were unaware of the collapse of WTC 7 on 9/11. [Zogby International, 5/24/2006; New York Times, 6/5/2006; Newsday, 9/1/2006] When Lee Hamilton, the former co-chair of the 9/11 Commission, is later questioned about this poll, he will say the figure of 42 percent of Americans believing there has been a cover up is “dispiriting, it’s an unusually high number” (see August 21, 2006). [Canadian Broadcasting Corporation, 8/21/2006] A previous Zogby poll found 49 percent of New York City residents agreed that some leaders “knew in advance” of the 9/11 attacks and “consciously failed to act” (see August 30, 2004).

Entity Tags: Zogby International

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

A poll by Ohio University and Scripps Howard News Service finds that a significant minority of Americans believe there was US government complicity in the 9/11 attacks. Thirty-six percent of the 1,010 respondents say they believe that US government officials “either assisted in the 9/11 attacks or took no action to stop the attacks because they wanted the United States to go to war in the Middle East.” Sixteen percent believe that secretly planted explosives brought down the Twin Towers, and 12 percent believe a military cruise missile, rather than a hijacked aircraft, hit the Pentagon. [Scripps Howard News Service, 8/3/2006; San Francisco Chronicle, 9/3/2006] An earlier poll had found that half of New York City residents believed government officials knew in advance of the attacks and consciously failed to act (see August 30, 2004).

Entity Tags: Ohio University, Scripps Howard News Service

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Thomas Kean and Lee Hamilton, the former chairman and vice chairman of the 9/11 Commission, release a book giving a behind-the-scenes look at their 20-month investigation of the September 11 attacks. [Associated Press, 8/4/2006] They begin their book, titled Without Precedent, saying that, because their investigation started late, had a very short time frame, and had inadequate funding, they both felt, from the beginning, that they “were set up to fail.” [Canadian Broadcasting Corporation, 8/21/2006; Rocky Mountain News, 8/25/2006] They explain the difficulties they faced in obtaining certain government documents and describe how the commission almost splintered over whether to investigate the Bush administration’s use of 9/11 as a reason for going to war. It says that if original member Max Cleland—a strong proponent of this line of inquiry—had not resigned (see December 9, 2003), the commission probably would not have reached unanimity. It also calls their gentle questioning of former New York Mayor Rudolph Giuliani during his May 2004 testimony, “a low point” in the commission’s handling of witnesses at its public hearings (see May 19, 2004). [Associated Press, 8/4/2006; New York Daily News, 8/5/2006; New York Times, 8/6/2006] Despite the problems it faced, when discussing his book with the CBC, Hamilton says he thinks the commission has “been reasonably successful in telling the story” of 9/11. [Canadian Broadcasting Corporation, 8/21/2006] Without Precedent, however, contains little new information about the events of 9/11. Intelligence expert James Bamford says there is “an overabundance of self-censorship by the authors.” [New York Times, 8/20/2006]

Entity Tags: Thomas Kean, Lee Hamilton

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Former 9/11 Commission co-chair Lee Hamilton.Former 9/11 Commission co-chair Lee Hamilton. [Source: CBC]Lee Hamilton, the former co-chair of the 9/11 Commission, gives a wide-ranging interview to the CBC about Without Precedent, a book he recently co-authored about his time on the 9/11 Commission (see August 15, 2006). In the interview he discusses the various “conspiracy theories” surrounding the events of 9/11. The interviewer, Evan Solomon, mentions to him a recent Zogby poll (see May 17, 2006) that found that 42% of Americans agreed that “the US government, and its 9/11 Commission, concealed or refused to investigate critical evidence that contradicts the official explanation of September 11th.” Hamilton calls this lack of trust in the Commission’s report “dispiriting,” but attacks the “conspiracy theory people,” saying, “when they make an assertion they do it often on very flimsy evidence.” He addresses some of the various “conspiracy theories” that have been put forward about 9/11:
bullet In order to contradict the allegation that the Twin Towers were brought down deliberately with pre-planted explosives, Hamilton says the WTC collapsed (see 8:57 a.m. September 11, 2001) because “the super-heated jet fuel melted the steel super-structure of these buildings and caused their collapse.” He adds, “There’s a powerful lot of evidence to sustain that point of view, including the pictures of the airplanes flying into the building.”
bullet With regard to the collapse of WTC Building 7 (see (5:20 p.m.) September 11, 2001), which some people claim was also caused by explosives, he argues, “[W]e believe that it was the aftershocks of these two huge buildings in the very near vicinity collapsing. And in the Building 7 case, we think that it was a case of flames setting off a fuel container, which started the fire in Building 7, and that was our theory on Building 7.” However, the interviewer points out that the 9/11 Commission’s final report does not actually mention the collapse of Building 7, and Hamilton says he does not recall whether the Commission made a specific decision to leave it out.
bullet In reply to a question about why the debris of Building 7 were moved quickly from the scene without a thorough investigation, even though nobody died in Building 7 and there was no need for rescue operations there, Hamilton responds, “You can’t answer every question when you conduct an investigation.”
bullet When asked whether Saeed Sheikh sent Mohamed Atta $100,000 for the 9/11 plot (see Early August 2001 and Summer 2001 and before), Hamilton replies, “I don’t know anything about it.” When the interviewer presses him about whether the Commission investigated a possible Pakistani Secret Service (ISI) connection to the attacks, Hamilton replies, “They may have; I do not recall us writing anything about it in the report. We may have but I don’t recall it.”
bullet Asked about Secretary of Transportation Norman Mineta’s claim that Vice President Dick Cheney was in the presidential bunker beneath the White House at 9:20 a.m. on 9/11 (see (Between 9:20 a.m. and 9:27 a.m.) September 11, 2001), almost 40 minutes earlier than the Commission claimed he had arrived there, Hamilton replies, “I do not recall.” When pressed, he expands, “Well, we think that Vice President Cheney entered the bunker shortly before 10 o’clock. And there is a gap of several minutes there, where we do not really know what the Vice President really did. There is the famous phone call between the President and the Vice President. We could find no documentary evidence of that phone call.”
bullet When the interviewer points out that Richard Clarke’s account conflicts with the Commission’s over what time authorization was received from Dick Cheney to shoot down Flight 93 (see (Between 9:45 a.m. and 9:56 a.m.) September 11, 2001 and (Between 10:00 a.m. and 10:15 a.m.) September 11, 2001), Hamilton retorts, “Look, you’ve obviously gone through the report with a fine-toothed comb, you’re raising a lot of questions—I can do the same thing.”
The interviewer also asks Hamilton whether he has any unanswered questions of his own about 9/11. Hamilton’s response is: “I could never figure out why these 19 fellas did what they did. We looked into their backgrounds. In one or two cases, they were apparently happy, well-adjusted, not particularly religious - in one case quite well-to-do, had a girlfriend. We just couldn’t figure out why he did it. I still don’t know.” [Canadian Broadcasting Corporation, 8/21/2006]

Entity Tags: Saeed Sheikh, World Trade Center, Richard (“Dick”) Cheney, Pakistan Directorate for Inter-Services Intelligence, Lee Hamilton, 9/11 Commission, Richard A. Clarke, Mohamed Atta, Norman Mineta

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

One of the ‘puffs of smoke’ observed during the Twin Towers collapses.One of the ‘puffs of smoke’ observed during the Twin Towers collapses. [Source: Richard Lethin]The National Institute of Standards and Technology (NIST) issues a seven-page fact sheet to counter alternative theories about the WTC collapses. NIST conducted a three-year study of the collapses, and concluded they were caused by the damage when the planes hit combined with the effects of the ensuing fires. However, many people—what the New York Times calls an “angry minority”—believe there was US government complicity in 9/11, and a recent poll (see July 6-24, 2006) found 16 percent of Americans believe the WTC towers were brought down with explosives. [National Institute of Standards and Technology, 8/31/2006; New York Times, 9/2/2006; Reuters, 9/2/2006] The fact sheet responds to 14 “Frequently Asked Questions.” Some of its key points include the following:
bullet Regarding whether NIST considered a controlled demolition hypothesis: “NIST found no corroborating evidence for alternative hypotheses suggesting that the WTC towers were brought down… using explosives… Instead, photographs and videos from several angles clearly show that the collapse initiated at the fire and impact floors and that the collapse progressed from the initiating floors downward until the dust clouds obscured the view.” However, it admits, “NIST did not test for the residue” of explosives in the remaining steel from the towers.
bullet Its explanation for puffs of smoke seen coming from each tower as it collapsed: “[T]he falling mass of the building compressed the air ahead of it—much like the action of a piston—forcing smoke and debris out the windows as the stories below failed sequentially.”
bullet Its explanation for a stream of yellow molten metal that poured down the side of the South Tower shortly before it collapsed (see (9:50 a.m.) September 11, 2001). NIST previously claimed it was aluminum, but this should not have been yellow in color: “Pure liquid aluminum would be expected to appear silvery. However, the molten metal was very likely mixed with large amounts of hot, partially burned, solid organic materials (e.g., furniture, carpets, partitions and computers) which can display an orange glow.”
bullet Regarding reports of molten steel in the wreckage at Ground Zero (see September 12, 2001-February 2002): “Any molten steel in the wreckage was more likely due to the high temperature resulting from long exposure to combustion within the pile than to short exposure to fires or explosions while the buildings were standing.”
bullet Regarding the collapse of WTC 7 (see (5:20 p.m.) September 11, 2001): “While NIST has found no evidence of a blast or controlled demolition event, NIST would like to determine the magnitude of hypothetical blast scenarios that could have led to the structural failure of one or more critical elements.” [National Institute of Standards and Technology, 8/30/2006] In response to the fact sheet, Kevin Ryan, the coeditor of the online Journal of 9/11 Studies, says, “The list of answers NIST has provided is generating more questions, and more skepticism, than ever before.” He says, “NIST is a group of government scientists whose leaders are Bush appointees, and therefore their report is not likely to veer from the political story.” [New York Times, 9/2/2006; Reuters, 9/2/2006]

Entity Tags: National Institute of Standards and Technology, Kevin Ryan

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

The National Institute of Standards and Technology (NIST) publishes a fact sheet responding to 14 “frequently asked questions” about its investigation into the collapse of the Twin Towers on September 11. Some of the key questions and answers are as follows:
bullet Regarding the question, “Why was the collapse of WTC 1 and 2 not arrested by the intact structure below the floors where columns first began to buckle?” NIST replies, “The vertical capacity of the connections supporting an intact floor below the level of collapse was adequate to carry the load of 11 additional floors if the load was applied gradually and 6 additional floors if the load was applied suddenly (as was the case).” As the number of floors above the points where the collapses initiated exceeded six (12 in the case of the North Tower, 29 for the South), NIST says, “[T]he floors below the level of collapse initiation were unable to resist the suddenly applied gravitational load from the upper floors of the buildings.”
bullet In answer to the question of “Why was physical evidence not collected immediately following the collapse of the WTC towers,” NIST says, “In the initial days and weeks following the WTC disaster, the emphasis was on rescue and later on recovery, necessitating the removal of steel and disturbing the collapse site.” It adds, “NIST did not receive the legal authority to collect and preserve physical evidence from a disaster/failure site until the National Construction Safety Team Act became law in October 2002.” The decision to rapidly scrap the remaining steel from the WTC was made shortly after 9/11 (see Shortly After September 11, 2001), but the destruction of this steel was strongly protested by some within the engineering and firefighting communities (see December 25, 2001 and January 4, 2002).
bullet In response to a question about why it did not use its subpoena authority during its investigation, NIST states that its “experience during the investigation was that it was able to obtain all essential documentary and visual evidence without the need to invoke subpoena authority.”
bullet In answer to the question, “Why didn’t NIST fully model the collapse initiation and propagation of WTC towers?” NIST says, “Once the collapse had begun, the propagation of the collapse was readily explained without the same complexity of modeling” as was used to determine the sequence of events leading up to the collapse initiation.
bullet During its investigation, NIST had selected several variables for its computer simulations, and then experimented with different possible values (see (October 2002-October 2005)). But it has been asked: “Why didn’t NIST consider the ‘base’ and ‘less severe’ cases throughout its analysis of the WTC towers? What was the technical basis for selecting only the ‘more severe’ case for its analyses?” Its answer is that, “Of the three [possible values], the more severe case resulted in the closest agreement with the visual and physical evidence.” [National Institute of Standards and Technology, 12/14/2007]
NIST published its final report on the Twin Towers collapse in October 2005 (see October 26, 2005). It released an earlier fact sheet answering previous “frequently asked questions” in August 2006 (see August 30, 2006). [National Institute of Standards and Technology, 8/30/2006]

Entity Tags: National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

The National Institute of Standards and Technology (NIST) releases a draft version of the final report of its investigation of the collapse of World Trade Center Building 7, the 47-story skyscraper which collapsed late in the afternoon of 9/11 (see (5:20 p.m.) September 11, 2001). [National Institute of Standards and Technology, 8/21/2008] The report describes NIST’s conclusions on how fires that followed the impact of debris from the north WTC tower’s collapse resulted in the eventual collapse of WTC 7. It evaluates the emergency response and building evacuation procedures, and provides 13 recommendations for construction of buildings in the future, and improved procedures and practices. [National Institute of Standards and Technology, 8/2008, pp. xiii pdf file] Some of the report’s key findings are:
bullet NIST describes its theory of what caused WTC 7 to collapse: “The probable collapse sequence… was initiated by the buckling of a critical interior column.… This column had become unsupported over nine stories after initial local fire-induced damage led to a cascade of local floor failures. The buckling of this column led to a vertical progression of floor failures up to the roof and to the buckling of adjacent interior columns to the south of the critical column. An east-to-west horizontal progression of interior column buckling followed, due to loss of lateral support to adjacent columns, forces exerted by falling debris, and load redistribution from other buckled columns. The exterior columns then buckled as the failed building core moved downward, redistributing its loads to the exterior columns. Global collapse occurred as the entire building above the buckled region moved downward as a single unit.” [National Institute of Standards and Technology, 8/2008, pp. xxxii pdf file]
bullet The collapse of WTC 7 “represents the first known instance of the total collapse of a tall building primarily due to fires. The collapse could not have been prevented without controlling the fires before most of the combustible building contents were consumed.” [National Institute of Standards and Technology, 8/2008, pp. 43 pdf file]
bullet The fires in WTC 7 “were ignited as a result of the impact of debris from the collapse of WTC 1, which was approximately 370 ft to the south.… The fires were ignited on at least 10 floors; however, only the fires on floors 7 through 9 and 11 through 13 grew and lasted until the time of the building collapse.” [National Institute of Standards and Technology, 8/2008, pp. xxxi-xxxii pdf file]
bullet “Even without the initial structural damage caused by debris impact from the collapse of WTC 1, WTC 7 would have collapsed from fires having the same characteristics as those experienced on September 11, 2001.” [National Institute of Standards and Technology, 8/2008, pp. 44 pdf file]
bullet “Had a water supply for the automatic sprinkler system been available and had the sprinkler system operated as designed, it is likely that fires in WTC 7 would have been controlled and the collapse prevented.” [National Institute of Standards and Technology, 8/2008, pp. 43 pdf file]
bullet Other skyscrapers had previously survived comparable fires. “The fires in WTC 7 were similar to those that have occurred previously in several tall buildings (One New York Plaza, 1970, First Interstate Bank, 1988, and One Meridian Plaza, 1991) where the automatic sprinklers did not function or were not present. However, because of differences between their structural designs and that of WTC 7, these three buildings did not collapse.” [National Institute of Standards and Technology, 8/2008, pp. 43 pdf file]
bullet NIST found that “temperatures did not exceed 300°C in the core or perimeter columns in WTC 7,” including the three interior columns that NIST says were the first to buckle in the collapse. “None of these columns were significantly weakened by elevated temperatures.” [National Institute of Standards and Technology, 8/2008, pp. 49-50 pdf file]
bullet NIST says it found “no evidence to suggest that WTC 7 was not designed in a manner generally consistent with applicable building codes and standards.” [National Institute of Standards and Technology, 8/2008, pp. 53 pdf file]
bullet The report concludes that neither explosives nor fuel oil fires fed by diesel tanks in WTC 7 played any role in the collapse (see August 21, 2008 and August 21, 2008). [National Institute of Standards and Technology, 8/2008, pp. 44-45 pdf file]
bullet However, the report points out that WTC 7 “and the records kept within it were destroyed, and the remains of all the WTC buildings were disposed of before congressional action and funding was available for this investigation to begin. As a result, there are some facts that could not be discerned, and thus there are uncertainties in this accounting. Nonetheless, NIST was able to gather sufficient evidence and documentation to conduct a full investigation upon which to reach firm findings and recommendations.” [National Institute of Standards and Technology, 8/2008, pp. xxxi pdf file]
NIST released a progress report in June 2004, which had included its “working hypothesis” at that time for the collapse of WTC 7 (see June 18, 2004). [National Institute of Standards and Technology, 6/18/2004] After suggestions are made by members of the public in response to the current draft report, NIST will release the finished version of the report in November 2008, which includes the same major findings and recommendations as the draft version (see November 20, 2008). [National Institute of Standards and Technology, 11/20/2008]

Entity Tags: World Trade Center, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

NIST’s ‘Final Report on the Collapse of World Trade Center Building 7.’NIST’s ‘Final Report on the Collapse of World Trade Center Building 7.’ [Source: National Institute of Standards and Technology.]The National Institute of Standards and Technology (NIST) releases the final report of its three-year investigation of the collapse of World Trade Center Building 7, the 47-story skyscraper which collapsed late in the afternoon of 9/11 (see (5:20 p.m.) September 11, 2001). This is the completed version of the report, and comes three months after a draft version was released for public comment (see August 21, 2008). NIST states that the new report “is strengthened by clarifications and supplemental text suggested by organizations and individuals worldwide in response to the draft WTC 7 report.” NIST conducted an additional computer analysis in response to comments from the building community, and made several minor amendments to the report. But, it says, “the revisions did not alter the investigation team’s major findings and recommendations, which include identification of fire as the primary cause for the building’s failure.” With the release of this report, NIST has completed its six-year investigation of the World Trade Center collapses, which it commenced in August 2002 (see August 21, 2002). The final report of its investigation of the Twin Towers’ collapses was published in October 2005 (see October 26, 2005). [National Institute of Standards and Technology, 11/20/2008; Occupational Health and Safety, 11/25/2008]

Entity Tags: World Trade Center, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

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