6. The Collapse

For the last few years I have spent a lot of time looking for answers to the questions still hanging over the events of September 11th, but the longer I’ve searched for answers the more the questions have mounted up. Perhaps the most extraordinary question I’ve struggled over is this one: what caused the collapse of the Solomon Brothers Building at the World Trade Center (also known as World Trade Center building 7)?

When I’d first come across the collapse of WTC7 in Griffin’s book I’d put it mentally aside, considering both irrelevant and more or less preposterous. Why bang on about another building collapse, I wondered, when it obviously has nothing to do with the main event. After all, WTC7 fell at 5:20 pm., almost seven hours after the collapse of the twin towers, and since no planes had impacted then it’s logical to conclude that the collapse must have been a consequence of structural damage sustained by falling debris from the twin towers. So what was the big fuss about?

Well, they say that seeing is believing. So it’s one thing to read about the spontaneous collapse of a forty-seven storey skyscraper, but quite a different thing to see it. And on this occasion, quite a number of amateur film-makers had captured the event; films that would on most other days have made the headline news. A huge Manhattan skyscraper melting into a cloud of dust. “Amazing, incredible, pick your word…” This is not my description but the spontaneous response of veteran newscaster Dan Rather, seeing the footage for the first time. Immediately afterwards, Rather adds:

“It’s reminiscent of those pictures we’ve all seen too much on television before, when a building was deliberately demolished by well-placed dynamite to knock it down.”

On seeing it then, the questions hanging over the collapse of WTC7 became perfectly obvious. For it certainly looks for all the world like a classic demolition: a tall building descending perfectly upright, sinking rapidly and smoothly beneath the city skyscape.

Telescoping into itself, almost magically, similar in kind to the earlier collapses of each of the twin towers – which likewise took only a few seconds – although WTC7 falls a little differently. Whereas each of the main towers had crumbled from around the impact zones, here the collapse clearly takes place at the base, which is indeed just like those films of every other explosive demolition I’ve ever seen. Not that appearance alone is proof of demolition, of course. But why had I never seen this extraordinary footage before I wondered?

Well, one reason is that thankfully no-one was killed, the building having been evacuated earlier in the morning. Whilst another, perhaps, is that like a good many things it was buried in the mayhem of that day. Lost in the chaos and forgotten along with – amongst many incidents – the capture of suspected terrorists driving a van loaded with explosives on the George Washington Bridge. Whatever happened to those other goons, I wonder.1

But there is an even more astonishing part to the story of the collapse of WTC7. For it turns out that the BBC had indeed reported on its collapse later in the evening (about the time many in Britain were asleep). As it transpires, however, they hadn’t reported the collapse quite late enough, because directly at the time of broadcast, WTC7 itself hadn’t actually collapsed!

Am I sure? Positively certain. The pictures are irrefutable. WTC7 is very clearly visible and very evidently intact, and almost directly over the shoulder of the news reporter Jane Standley as she is exaggerating its earlier demise. Indeed WTC7 was to stand for a good ten minutes longer, outlasting the live link, which being abruptly lost may perhaps have saved our reporter the indignity of turning around to see it disappear for real.

When recordings of this blunder first appeared on the internet, the BBC were quick to dispel all rumours. We didn’t receive a special advance warning of the WTC7 collapse, they assured us, and in this regard I happen to believe them. For starters, they weren’t first to report the event – that dubious honour goes to CNN, who reported its collapse an hour earlier again.2 But don’t the chaps at CNN or the BBC actually check their information before a broadcast? Obviously, this is a rhetorical question.

There is another point here: for how did anyone have such expert foresight to know that WTC7 was even on the point of catastrophic failure? Was it simply a piece of inspired guesswork from whoever at Reuters first released the story? And what had led newscaster Philip Hayton into speculations that:

“It seems that this was not the result of a new attack. It was because the building had been weakened during this morning’s attacks.”

Please remember that this is at a time when the building is still standing perfectly square!

And there’s very little precedence for steel-framed skyscrapers suffering such catastrophic collapse. In fact prior to September 11th there were precisely no cases in history. So given that the North and South Towers had apparently been felled due to the highly exceptional impacts of the jetliners, then why should anyone at all – let alone a BBC newscaster – begin supposing that a different skyscraper, a few blocks removed, and hours later, would to succumb to an exactly same fate?


The BBC has very recently had a whole lot more to say about the collapse of WTC7. Since I penned my remarks above, they have devoted a further hour long documentary to this single issue.3, its release timed to coincide with the soon to be announced final conclusions from the National Institute of Standards and Technology (NIST). And in contrast to the earlier BBC broadcast, on this second outing of The Conspiracy Files: 9/11, the programme did at least address the central issues of the case, rather than drawing attention only to the least plausible and most peripheral of the many claims.

For instance, it presented the testimony from eyewitnesses who said they definitely hadn’t heard explosions in any of the towers, which challenges the testimony of the many others, including William Rodriguez, who are equally adamant that they did.4 Rodriguez indeed goes a great deal further.

Aside from describing an explosion in the basement that quite literally blew him off his feet, and caused serious injury to many around him, he further claims that this basement explosion occurred seconds prior to the impact of the first plane. But this got no mention of course – after all the programme was about the collapse of WTC7, “the third tower”. So we heard instead from an eyewitness who said he saw substantial fires in WTC7, fires which had caused its walls to visibly bow outwards, such that it was quite obviously in imminent danger of collapsing. Yet this again is a direct contradiction to the accounts of others who insist that the damage appeared more superficial.5 But then eyewitness reports are notoriously unreliable. So who are we to believe?

One person who featured in the programme was Barry Jennings, the deputy director of the Emergency Services Department of the New York City Housing Authority. Jennings along with another man called Michael Hess, of New York City’s corporation counsel, had independently headed to the Office of Emergency Management’s Emergency Operating Center. The EOC was a special bomb-proof bunker which had years earlier been built high up into the 23rd floor of WTC7.

Jennings says that he was expecting to be met by Mayor Rudy Giuliani, but instead had found the place had been deserted, going on to describe how they even found half-eaten sandwiches and still warm cups of coffee. Wondering what was going on, Jennings says he phoned down and was told to leave the building immediately. However, before they had reached the lobby, Jennings says there was a big explosion, which forced both men to climb back to the eighth level where they remained trapped for several hours.

Jennings, still bruised and covered in dust, relates this whole story via a live link to the on-the-scene reporter for ABC news. Shortly after their rescue by fire-crews, another on-the-spot reporter, Frank Ucciardo had managed to get a separate interview with Michael Hess. Also aired live, this time on Channel 9 news, Michael Hess’s own first account of events, accurately corroborates the story being told by Jennings. Yet according to the timeline of their arrival and rescue, their reports of the big explosions inside WTC7 must have occurred prior to the collapse of the towers. What this means of course, is that Jennings and Hess could not have mistaken the explosion inside the separate WTC7 with damage caused by falling debris – which certainly did smash through one side of the building. Indeed, on a second interview, conducted in mid 2007 by Dylan Avery and Jason Bermas (and to be included in the final version of Loose Change), Avery raises the point directly. Jennings sticks to his original account.

On the BBC documentary, we also hear testimony from Barry Jennings, however Jennings now seems less certain. Although in actual fact, he does not retract any of his original statements, significantly he makes no mention of the big explosion that in the immediate aftermath, both he and Michael Hess, had independently cited as the original cause of their entrapment.

In response to the BBC programme, Dylan Avery has now released the uncut version of the interview with Barry Jennings he made for Loose Change6:

“My mind is still there, you know,” Jennings says, responding to Dylan Avery’s invitation to make any final comments, “That day I’ll never forget. And the explanations that were given me: totally unacceptable – totally unacceptable.”

Sadly, Barry Jennings died on August 19th 2008, only a month after his appearance on BBC and just days prior to the release of the NIST Final Report on the collapse of WTC7.

[blip.tv http://blip.tv/play/xRHBsHoC?p=1 width=”550″ height=”443″]


The BBC programme makers also paid attention to the reaction of Dutch demolition expert, Danny Jowenko, who on being shown the collapse of WTC7 for the first time (unaware of the context of what he was seeing and therefore making his judgement without any prejudice) came to the unequivocal conclusion that here was a controlled demolition.7

However, a different American demolition expert called Mark Loizeaux, who is the President of Controlled Demolition, apparently begs to differ. And so that’s again that.

Different experts have reached different conclusions: stalemate; with the implication that expert opinion is also unreliable. But instead of leaving matters there, the programme makers might instead have approached Jowenko directly, to ask whether he remained sure of his convictions, given the disagreement they’d found from Loizeaux and others. They didn’t, but had they done so, they’d have found Jowenko remains just as adamant as when he’d first watched the footage, whilst offering cautious reason to doubt the judgement of anyone from the trade who’s reliant on future business in America:

“When the FEMA makes a report that it came down by fire, and you have to earn your money in the States as a controlled demolition company and you say, “No, it was a controlled demolition”, you’re gone.”8

In such a fashion then, the programme makers set about the theory for controlled demolition, repudiating selected eyewitness testimony by presenting contrary testimony and refuting expert testimony with further expert testimony: every positive eliminated by a cancelling negative. A process of neutralisation, in which all testimony would be equal, but for the fact that it is opposition to the official story, rather than the official story as such, that is under scrutiny.

This is not the proper format of a journalistic investigation, where “there’s nothing to see here…” is the message again and again. The best hope, the narrator concludes lamely, is that following NISTs final report, the victims and the families of the victims might at last be allowed to move on. By falsely insinuating that this is all a lot of hokum, cooked up by a bunch of self-interested outsiders, the programme finally closes, just as the first had, with an outrageously sweeping misrepresentation of the truth movement itself.


But there was one way that we could have been absolutely certain whether or not WTC7 had been demolished. A proper forensic examination of the steel would have unequivocally settled the matter. The lessons learned from such a full forensic investigation might also have protected buildings and people in the future – after all, this was an unprecedented collapse (as everyone agrees) – and if fire alone had caused the structure to fail then we need to know exactly how. Such analysis is not merely an academic exercise, but potentially a matter of life and death. Yet, we learn that not a single sample of steel was saved from WTC7. Not one. When surely such a wholesale destruction of evidence would be nothing short of criminal.

And so we learn that as early as January 2002, Bill Manning, the editor in chief of Fire Engineering magazine, was already shining a spotlight on the altogether slipshod investigation, castigating FEMA (the Federal Emergency Management Agency) in no uncertain terms, and candidly expressing his concerns of a deeper cover-up:

“Fire Engineering has good reason to believe that the “official investigation” blessed by FEMA and run by the American Society of Civil Engineers is a half-baked farce that may already have been commandeered by political forces whose primary interests, to put it mildly, lie far afield of full disclosure.”9

Concerns that raise yet another important question: on whose authority was this removal of evidence permitted. The BBC programme touched on all of this, and yet it failed to delve into the matter at all.

“As things now stand and if they continue in such fashion, the investigation into the World Trade Center fire and collapse will amount to paper- and computer-generated hypotheticals.”

writes Manning again (in the same article), correctly foreseeing that in the absence of all forensic analysis, the future teams of investigators, such as those working at NIST would have to rely solely on computer simulations.

Now in fairness this has obviously made their task a great deal tougher than it ought to have been, and so it may perhaps be forgiven if their original report of 200510 didn’t bother to present any theory of any kind to account for the collapse of WTC7. However, they have since spent a further three years (seven in total) tweaking the parameters of their finite-element analysis routines and at last they might have figured out a possible mechanism. The entire collapse must have been caused by ordinary office fires, they’ll say, because what is NIST’s alternative? To return with yet another report that explains why they still haven’t got a clue, or as FEMA put it rather more tortuously in the conclusion to their own first report that: “…the best hypothesis has only a low probability of occurrence.”11

Yes, the scientists and engineers at NIST have been tasked with a seriously tricky problem. To establish a mechanism involving such rapid and simultaneous failure to ensure a perfectly symmetrical collapse at close to free-fall speeds. A failure instigated by fires which were at their most intense on the lower and middle levels, yet causing a collapse that began with the penthouse, and then, almost immediately, shattered the building progressively from the base upwards. A process that caused the building to fold inwards, pulverising itself into dust, and causing what little rubble remained to tumble almost vertically rather than taking paths of least resistance (and with other parts toppling over). And a mechanism that could leave a neat pile of smouldering remains that would continue to glow for more than a month afterwards.

They’ll be doing well to account for any of this, basing their theory on randomly situated office fires, but still one piece of evidence remains that no theory of natural collapse can ever provide a feasible account for: it is the numerous reports from first-responders who saw “pools” and “rivers” of molten steel, with one firefighter comparing the scene to being “like a foundry”.12 In order to see why this is such a big ask, I’ll need to make a considerable digression to more closely consider all of the physics involved. However, since many readers will find such technical arguments tiresome, I have decided to save that more detailed analysis for a separate Appendix B.


For now I wish leave aside any closer inspection of questions surrounding the collapse of WTC7 and the other towers. The NIST final report has been published, and as expected it explains everything in terms of the fires, which means that once again they have failed to take account of all the evidence (the various reports of molten steel being quite impossible to square with such a low temperature theory). I could go on much further and talk about the unexplained sulphidation of the samples that were tested by FEMA, and other evidence supporting theories that a substance like thermite could have been used to cut through the girders13. I realise that for many people the very idea that a criminal branch of the US administration would, or even could, have planted explosives in the buildings represents an apparent leap into madness. So let’s move on.

Let’s also now leave aside Thierry Meyssan’s theory that it was a missile and not a plane that hit the Pentagon, which opens another can of worms again. There’s more than enough food for thought without the missing planes and the unparalleled collapse of buildings. My real aim here has been to show that far from being madness, the theory that the buildings were demolished, mostly especially in the strange case of WTC7, still remains the only available theory that accounts for every piece of the surviving evidence.

The collapse of WTC7 has every feature associated with a controlled demolition and there is nothing about the collapse that has been shown to deviate from the characteristics of other controlled demolitions; whereas, for it to have collapsed ‘naturally’ in such a characteristic way would require nothing less than a miracle.

When it comes to the case of WTC7, the objections put forward by “debunkers” of the controlled demolition theory tend to speculate on the hows and whys: how could the building have been rigged with explosives? and why would anyone blow up WTC7 in the first place? But the answer to such questions we can only speculate on, where speculation inevitably means coming up with some additional “conspiracy theories”. The better approach, I think, is simply to call for a new investigation that is amply funded, fully independent and encouraged to investigate every last detail of all the events of 9/11. For on what grounds would anyone oppose the re-opening of the inquiry into 9/11, other than the spurious claim that we already know all the answers?

1“Two suspects are in FBI custody after a truckload of explosives were discovered around the George Washington Bridge. That bridge links New York to New Jersey over the Hudson River. Whether the discovery of those explosives had anything to do with other events today is unclear, but the FBI, has two suspects in hand, said the truckload of explosives, enough explosives were in the truck to do great damage to the George Washington Bridge…” Transcript of Dan Rather’s CBS report broadcast live to millions of viewers on September 11th 2001. American security services overnight stopped a car bomb on the George Washington Bridge connecting New York and New Jersey. The van, packed with explosives, was stopped on an approach ramp to the bridge. Authorities suspect the terrorists intended to blow up the main crossing between New Jersey and New York, Army Radio reported.” taken from report in Jerusalem Post on Wednesday 12th September 2001.

2Here the live reporter Aaron Brown says: “We are getting information now that one of the other buildings, building 7 in the world trade center complex, is on fire and… has either collapsed or is collapsing, and I… I… Y..You, to be honest, can see these pictures a little bit more clearly than I.” But actually World Trade Centre building 7 is shown in close-up and quite clearly still standing.

3“The conspiracy files: 9/11 – The third tower”, directed by Mike Rudin, and first broadcast BBC2 on Sunday 6th July, 2008.

4There are many dozens of reports from eyewitnesses, first responders, and also from TV reporters of explosions inside the WTC. These can be found posted on internet sites or else cut together into short presentations on You Tube. I have decided to cite the account of just one of those eyewitnesses. Craig Bartmer, a NYPD officer, heard the breaking news-story on the television and made the decision to join the emergency teams in order to help his colleagues. As a consequence he saw the collapse of WTC7 from very close quarters: “I was real close to Building 7 when it fell down – and – running away from that sucked. That’s one of the things I live with all the time – and – I don’t [know] but that didn’t sound like just a building fall[ing] down to me, as I was running away from it. There’s a lot of eyewitness testimony down there about hearing explosions. I didn’t see any reason for that building to fall down the way it did. And a lot of guys should be saying the same thing. I don’t know what the fear is in coming out and talking about it – I don’t know – but it’s the truth.” Transcript made by the author of an interview with Craig Bartmer posted on youtube.

5Craig Bartmer again: “I walked around it – I saw a hole. I didn’t see a hole big enough to knock a building down, though. Saw, you know, yeah there was definitely fire in the building, you know but, I didn’t hear any, you know – maybe this is movie crap – you know, I didn’t hear any creaking or I didn’t hear any – any indication that it was going to come down. And all of a sudden the radios exploded and everyone starts screaming “get away! get away! get away from it!” And I was like a deer in headlights. And I look up and – it was nothing I’d ever imagine seeing in my life. You know the whole thing started peeling into itself. And I mean there was an umbrella of crap seventy [?] feet over my head that I just stared at. And some one grabbed my shoulder and I started running. And the shit’s hitting the ground behind me. And the whole time you’re hearing THUM, THUM, THUM, THUM – so I think I know an explosion when I hear it. ” Craig Bartmer also worked in the rubble at Ground Zero, helping out in the original rescue effort, and as a consequence has since developed severe respiratory illness due to inhaling toxic dust from the site. Like many of the first responders, he also suffers from Post-Traumatic Stress Disorder, although he is keen to point out that this does not impair his memory of the events.

6Dylan Avery has since explained his decision to release the uncut Barry Jennings interview on his own website at http://www.loosechange911.com. It reads as follows:

“I’ve been sitting on this interview for a while, but after viewing the latest BBC piece on WTC7, I feel the time has come to release it in its entirety. After locating Barry in mid 2007, Jason and I visited him and he graciously granted us an interview during a lunch break. He had agreed to grant us an interview under the conditions that we, at no time, associate his interview with his place of employment.

Jason and I were so thrilled with the content of the interview that we decided to release a few bits and pieces of it on both our show and Alex’s. A few months later, as the film was nearing completion, I called Barry again to touch base and see how things were going. It took him a bit to remember who I was, but as soon as he did, he began complaining about phone calls to his place of employment and that he was in danger of losing his job. He requested to have his interview pulled from Loose Change, and I honored his request.

Fast forward to February, 2008, where I’m doing an interview with the BBC, and I’m informed by their crew that Barry told them the reason he asked for it to be pulled was because of the article on Prisonplanet claiming he was stepping over dead bodies, which he denies saying. I call Barry to attempt to rectify the situation, and he is adamant that he did not use the phrase “we were stepping over people”

Fast forward one more time to two days ago, when the BBC piece finally aired. I now feel an obligation to release his interview, in its entirety, into the public where it belongs for three reasons:

1) To see the difference between the interview he gave us, and the interview he gave the BBC.

2) To establish Barry’s timeline in his own words.

3) To preserve his testimony, in his own words, for the historical record.

I have remained true to my word and kept his interview out of the film, however, I can no longer keep it from the public. They deserve to hear Barry’s story, out of his own mouth.

As I say in the end of the video, I would appreciate it if Barry could enjoy his privacy and live his life in peace. My intention with releasing this is so his story can be told, not to cause him any further grief or suffering

7Danny Jowenko is the Proprietor of Jowenko Explosieve Demolitie B.V., a European demolition and construction company, with offices in the Netherlands. Founded 1980, Jowenko Explosieve Demolitie is certified and holds permits to comply with the Dutch Explosives for Civil Use Act and the German Explosives Act. Jowenko’s explosives engineers also hold the German Certificate of Qualifications and the European Certificate for Shotfiring issued by The European Federation of Explosive Engineers. Here is a transcript of Jowenko’s remarks about the collapse of WTC7, taken from a report for Zembla, Dutch Television from 2006:

DJ: That is controlled demolition

Reporter: Absolutely?

DJ: Absolutely. It’s been imploded. It’s a hired job done by a team of experts.

Reporter: But it happened on 9/11

DJ: The same day? – Are you sure? – And you’re sure it was the 11th? – That can’t be.

Reporter: Seven hours after the World Trade Center

DJ: Really? – Then they worked hard…

8The following is a telephone interview with Jeff Hill from February 22th 2007:

Jeff Hill: I was just wondering real quickly, I know you had commented on World Trade Center Building 7 before.

Danny Jowenko: Yes, that’s right.

J H: And I’ve come to my conclusions, too, that it couldn’t have came down by fire.

D J: No, it — absolutely not.

J H: Are you still sticking by your comments where you say it must have been a controlled demolition?

D J: Absolutely.

J H: Yes? So, you as being a controlled demolitions expert, you’ve looked at the building, you’ve looked at the video and you’ve determined with your expertise that —

D J: I looked at the drawings, the construction and it couldn’t be done by fire. So, no, absolutely not.

J H: OK, ’cause I was reading on the Internet, people were asking about you and they said, I wonder — I heard something that Danny Jowenko retracted his statement of what he said earlier about World Trade Center 7 now saying that it came down by fire. I said, “There’s no way that’s true.”

D J: No, no, no, absolutely not.

J H: ‘Cause if anybody was — Like when I called Controlled Demolition here in North America, they tell me that , “Oh, it’s possible it came down from fire” and this and that and stuff like that –.

D J: When the FEMA makes a report that it came down by fire, and you have to earn your money in the States as a controlled demolition company and you say, “No, it was a controlled demolition”, you’re gone. You know?

J H: Yeah, exactly, you’ll be in a lot of trouble if you say that, right?

D J: Of course, of course. That’s the end of your — the end of the story.

J H: Yeah, ’cause I was calling demolitions companies just to ask them if they used the term, “Pull it” in demolition terms and even Controlled Demolitions, Incorporated said they did. But the other people wouldn’t — didn’t want to talk to me about Building 7 really because obviously ’cause they knew what happened and they didn’t want to say it.

D J: Exactly .

9“Did they throw away the locked doors from the Triangle Shirtwaist Fire? Did they throw away the gas can used at the Happyland Social Club Fire? Did they cast aside the pressure-regulating valves at the Meridian Plaza Fire? Of course not. But essentially, that’s what they’re doing at the World Trade Center. For more than three months, structural steel from the World Trade Center has been and continues to be cut up and sold for scrap. Crucial evidence that could answer many questions about high-rise building design practices and performance under fire conditions is on the slow boat to China, perhaps never to be seen again in America until you buy your next car. Such destruction of evidence shows the astounding ignorance of government officials to the value of a thorough, scientific investigation of the largest fire-induced collapse in world history. I have combed through our national standard for fire investigation, NFPA 921, but nowhere in it does one find an exemption allowing the destruction of evidence for buildings over 10 stories tall.” extract from article in Fire Engineering, January 2002, written by editor in chief Bill Manning, that called for a comprehensive investigation into the WTC collapse entitled: “Burning Questions…Need Answers”

10FEMA’s original explanation of a “pancake collapse” of the twin towers was rejected by a later investigation by the National Institute of Standards and Technology (NIST), which was issued in October 2005 as: “Final Report on the Collapse of the World Trade Center Towers.”

11“The specifics of the fires in WTC7 and how they caused the building to collapse remain unknown at this time. Although the total diesel fuel on the premises contained massive potential energy, the best hypothesis has only a low probability of occurrence.” Federal Emergency Management Agency World Trade Center Building Performance Study, published May 2002.

12There are a great many reports of molten steel and also of the intense fires that persisted for weeks after the collapse and so this is necessarily only a small sample.

A member of the New York Air National Guard’s 109th Air Wing was at Ground Zero from September 22 to October 6. He kept a journal on which an article containing the following passage is based: “Smoke constantly poured from the peaks. One fireman told us that there was still molten steel at the heart of the towers’ remains. Firemen sprayed water to cool the debris down but the heat remained intense enough at the surface to melt their boots.” extract from “Serving on ‘sacred ground’“, National Guard, Dec 2001 by Guy Lounsbury.

Another article in The Newsletter of the Structural Engineers Association of Utah that describes a speaking appearance by Leslie Robertson (structural engineer responsible for the design of the World Trade Center) contains the following passage: “As of 21 days after the attack, the fires were still burning and molten steel was still running.”

A report in the John Hopkins Public Health Magazine (2002) entitled “Mobilizing Public Health” says: “It is 4 a.m. in New York City as four researchers from the School enter the site of the World Trade Center disaster on foot. Each is lugging from 50 to 90 pounds of air-monitoring equipment onto Ground Zero. In the dark, the tangled pile of wreckage takes on a distinctly hellish cast. ‘Fires are still actively burning and the smoke is very intense,’ reports Alison Geyh, PhD. ‘In some pockets now being uncovered, they are finding molten steel.'”

Whilst from “Messages in the Dust: What are the lessons of the environmental health response to the terrorist attacks of September 11th” written by Francesca Lyman, published by the National Environmental Health Association in September 2003 we read the following: “Into this devastated, almost apocalyptic war zone of a landscape marched a host of different players from government, nonprofit groups, hospitals and medical institutions, and private industry. To some, it was an environmental health disaster from the very first. “Standing down there, with your eyes closed,” says Ron Burger, a public health advisor at the National Center for Environmental Health, Centers for Disease Control and Prevention, who arrived in New York to help September 11th but didn’t arrive to the Ground Zero the site until the night of September 12th, “it could have been a tornado or an avalanche or a volcano.” A veteran of disasters from the Mississippi floods Mt. St. Helens, Burger said it reminded him most of the volcano, if he forgot he was in downtown Manhattan. “Feeling the heat, seeing the molten steel, the layers upon layers of ash, like lava, it reminded me of Mt. St. Helen’s and the thousands who fled that disaster,” he said.”

13I refer the reader to Appendix C of the “Federal Emergency Management Agency World Trade Center Building Performance Study, published May 2002, which is entitled “Limited Metallurgical Examination”. The conclusion states that: “The severe corrosion and subsequent erosion of Samples 1 and 2 are a very unusual event. No clear explanation for the source of sulfur has been identified.” I sent a copy of this Appendix to a friend who happens to have studied his PhD in the study of corrosion fatigue. He sent back the following rather technical reply: Erosion is speculated upon but the author seems to conclude that it is corrosion that caused the gross sectional thinning.

First of all, considering high temperature corrosion in the absence of sulphur, such corrosion rates are unacceptably high for non-stainless steels to be employed in service at these temperatures. Iron oxidises rapidly to wustite (FeO) above 570 deg C. Nevertheless, this doesn’t seem to cause a big problem in itself for structural steels within the timescale of a building fire as evinced by the fact that no other buildings in the world have collapsed due to failure of structural steel alone in severe fires.

I don’t know exactly what sulphur does to structural steel at 1,000 deg C but it is generally a highly significant element in all forms of corrosion (i.e. high temperature oxidation such as this and lower temperature aqueous corrosion) and is generally very aggressive. Iron sulphide (FeS) is soft. (Sometimes sulphur is added deliberately to steel to form iron sulphides so that cheap components can be easily machined.) I would guess that there’s a very high chance that the presence of sulphur would greatly accelerate the corrosion of steel at this temperature.

The author comments about how the rates of corrosion are unknown. This is probably why he goes on to say that it may have occurred in the ground after the collapse since he doesn’t know whether there would have been sufficient time for this amount of corrosion to have occurred in the fire before the collapse. This is obviously a very important point. If sulphur was implicated in the collapse, we would have to ask how it got to where it was. For a large city centre office tower block, no obvious source comes to mind! I wonder if he was being diplomatic when he suggested that it may have occurred slowly in the ground after the collapse. I doubt if there are any corrosion rate data already available for this situation as it is too extreme to be useful to anyone (except forensic fire investigators looking at this unique case). Data would probably need to be specially generated by experiment to determine roughly what rates are plausible.

If the sulphidation occurred in the ground, then we need to ask, how did the sulphur get to be there. I think the whole thing looks highly suspicious.”


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