NIST Replies to Three Questions: WTC7, Nano-Thermite, & Microspheres


With the help of a volunteer from, Wayne Coste, three members of my local community and I engaged in a correspondence with NIST that was “shepherded” by our congressman’s office.

Our complete correspondence can be found here: All Three Letters and Responses.

In the first letter we asked three questions: (1) How does NIST explain building 7’s 2.2 seconds of free fall, and the apparent visual discrepancy between video of the collapse and NIST’s visualization based on their computer simulation? (2) How does NIST explain the documented presence of nano-thermite in the WTC dust? (We cite the relevant article.) And, (3) how does NIST explain he the abundance of iron-rich microspheres in the dust? Our other two letters are follow-ups regarding NIST’s initial answers. Our third letter summarizes and puts the whole thing in context.

Below I’ve pasted the text of (most of) our third letter, which summarizes the first two. Below that I’ve included NIST’s final response.


Dear Director Gallagher & Deputy Director Grosshandler,

We are writing as signatories of the petition and as concerned residents of Congressional District NY-23. Congressman Bill Owens, though he does not express agreement with our own assessments, has graciously consented to facilitate this constituent inquiry to NIST.

Apparently, despite our effort at clarity in putting forward our questions and concerns, we somehow failed to convey clearly enough what we regard as the most salient issues. For, despite your efforts to answer (and we do appreciate these efforts), none of the initial issues we raised have actually been addressed, much less convincingly answered. So, in this letter we will attempt to clarify. (Remember that our second letter, and your second response, dealt only with question 1.)

Original Question 1:

First, in the collapse of Building 7, [a] how do the NIST studies account for the rapid collapse (at free-fall speed for 2.2 seconds) directly downward through the area of maximum structural resistance? Such rapid collapse is simply not possible without all support being simultaneously removed. Furthermore, [b] NIST's own multi-million dollar studies developed finite element structural models to illustrate the collapse, but what their models showed does not correspond to video of the actual event as shown in the video comparison. … This discrepancy needs to be addressed.

Review of correspondence:
First Letter to NIST
In our letter dated March 30, 2011, we asked the above question.

NIST Response to our First Letter
In a letter dated May 6, 2011, you conclude by stating “The timing of the collapse in the models developed by NIST agrees quite well with the video evidence of the collapse.”
Second Letter to NIST
In our second letter, we provided more background on the rapid symmetrical descent of WTC Building 7 and contrasted the time sequence photos of the collapse with time sequences in the NIST Finite Element Analysis simulations:

[See PDF of the relevant page of our letter]

In the video footage above we are looking at the building from the north, with a bit of the west also visible. Below we add a snapshot of NIST’s model of the building from three different angles.

[See the above link]

Figure 4-63, entitled: “Exterior buckling after global collapse initiation.” NIST NCSTAR 1-9A, “Global Structural Analysis of the Response of World Trade Center Building 7 to Fires and Debris Impact Damage” (November 2008). p.111.

We did not see agreement between the video and models and asked three specific questions in order establish the basis for the claim that NIST’s model “agrees quite well with video evidence of the collapse.”

NIST’s Response to our Second Letter
In a letter dated August 3, 2011, you respond “[the claim that] ‘…the timing of the collapse in the models developed by NIST agrees quite well with the video evidence of the collapse,’ referred to the time period from the start of the [theorized] cascading failure of floors surrounding Column 79 to global collapse as indicated by the initial downward motion of the north face roofline, a total of 12.9 seconds” (emphasis and bracketed clarification added).

Analysis and Clarification
That means that the end of the period during which the visualization and the video are claimed to agree is before the 2.2 seconds of freefall even starts. That is, the claimed agreement is up to the point indicated as “0 seconds” in the first frame of footage shown above. We are asking about what happens after that—when the main exterior frame of the building freefalls.

Thus, our original underlying question (1b) remains: with respect to the time period during which the building was collapsing at freefall, how do you account for the difference, so apparent in the frames shown above, between your model and the video footage?

Regarding the first part of the question (1a), explaining the 2.2 seconds of freefall, we don’t find an answer. In the only oblique mention of the salient period, it is referred to dismissively as “only a portion of the visible descent.” That is true. But of what significance is the fact that it is only a portion of the collapse? We are talking about 2.2 seconds, during which the building fell over 100 feet. Whether it is only a portion of the fall or not, it still needs to be explained. Further, this part of the collapse is described in your response as “near-freefall acceleration” (emphasis added). We don’t mean to quibble, but the final version of the NIST report clearly acknowledges not just near-freefall acceleration, but actual freefall. It describes “a freefall descent over approximately eight stories at gravitational acceleration for approximately 2.25 [seconds].” So, again, this is the issue. We would like an explanation for how the building could have collapsed, for over 100 feet in absolute freefall. One reason we find NIST’s admission of freefall to be stunning, and calling out for an explanation, is that at freefall all of the potential energy of the building is being converted to kinetic energy, so there is no energy left to do any work—no energy to bend things, or break things, or push things out of the way.

Original Question # 2
Second, how does the NIST investigation explain the ubiquitous presence of unexploded nano-particles of thermite in numerous samples of dust from the 9/11 disaster? This is an intensely engineered substance which could not have been spontaneously created from materials at hand. The dust should not contain these very significant particles and their presence needs to be explained.

We were asking for an explanation of the presence of a substance that appears to be a form of nano-thermite found in numerous samples of WTC dust and documented in a peer-reviewed article published in The Open Chemical Physics Journal. The article concludes, “[T]he red layer 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.” Your answer does not address the issue. In your first letter (stamped May 6, 2011), you write:
“[E]vidence from photographs and videos did not support a hypothesis of controlled demolition using an incendiary material (e.g. thermite) placed prior to either collapse.”
But we are not asking about photographs or videos (though we do not agree that such evidence does not support the use of some form of thermite ). We are asking how NIST explains the presence of what appears to be bits of nano-thermite in the WTC dust. Can the presence of a highly energetic and clearly engineered substance, which seems to not at all belong in the WTC dust, simply be ignored? Is there some innocent explanation for the presence of this energetic material in the WTC dust? If so, what is it? (Or, do you deny that it is present? If so, on what basis?) Surely this cannot be written off as trivial or irrelevant. (We will return to this issue below, as it relates to what seems to be your ultimate answer to both Question 2 and Question 3.)

Original Question #3:
Third, how does the NIST investigation account for the presence of iron-rich microspheres, again ubiquitous in numerous samples of WTC dust. … Such microspheres would logically be a result of explosive aerosolization of molten iron, thus it seems critical to explain the presence of these microspheres, lacking molten iron or explosives as officially accepted components of the 9/11 disaster.

The presence of iron-rich micro-spheres was so ubiquitous in the dust that the RJ Lee Group took these to constitute part of the “WTC Dust signature.” There can be no serious doubt that these particles are there. We asked how NIST accounts for their presence.

NIST’s Ultimate Non-Answer to Questions 2 and 3:
You write, “The documentation of trace metals, organic compounds, and other materials in the dust and air from the vicinity of the WTC disaster was outside the scope of NIST’s investigation.” But the relevance of the presence of significant quantities of unreacted nano-thermite should be obvious. And as for the iron-rich microspheres, they suggest temperatures far in excess of those presumed to have existed. If these particles can’t be explained, then that presents a serious problem for NIST’s theory of what happened. How does NIST justify declaring well-established physical evidence that creates a serious problem for its theory to be “outside the scope” of its investigation? We acknowledge that there is a distribution of labor, with USGS and FEMA as well as non-governmental organizations, such as the RJ Lee Group, performing tasks and investigations that NIST need not duplicate. But, to the degree that these studies are relevant to NIST’s theory, NIST must obviously take them into consideration. These issues should not automatically be regarded as “outside the scope” of the investigation just because some other agency or organization did the legwork. Further, the existence of extremely high temperatures, which is a critical issue here, is corroborated by multiple accounts of “molten steel,” and the bright orange “flow of glowing liquid” that can be seen on video of the South Tower just before collapse. In light of all this, and more, it seems to us that explanations of these phenomena are in order, since they at least appear to be inconsistent with NIST’s account. But to simplify the issue we are asking just about the micro-spheres and the nano-thermite. (We only mention the other lines of evidence here to clarify the relevance of these spheres to NIST’s theory, and to point out that the existence of prima facie evidence for anomalously high temperatures in firsthand reports and in video footage heightens the need to investigate potentially corroboratory lines of evidence that are more open to scientific investigation, such as these micro-spheres.)

Thank you for your assistance. We would, of course, not be pressing for answers if we did not think there were very significant implications. In answering, please pay special attention to the questions and requests that appear in bold.

[End of Letter #3]

Text of NIST’s response to the above letter:

In response to your letter received April 17, 2012, by NIST Director Patrick Gallagher and me regarding the agency’s investigation of the collapses of Building 1, 2, and 7 at the World Trade Center complex on Sept. 11, 2001, NIST believes that it has previously provided answers to all of your questions.

With respect to your Question 1 regarding the timing of the collapse and the agreement of the models to the video evidence, NIST has clearly documented the approach used to time the collapse and to validate the models. Please refer to number 11 of our Frequently Asked Questions at the following link:

Also, please refer to NCSTAR 1A Chapter 3, in particular, Sections 3.4.6 and 3.5 at:

Finally, we suggest that you refer to NCSTAR 1-9A Chapter 4 at:
Which provides a detailed explanation of the modeling approach and comparison to observable data.

Regarding your Questions 2 and 3, please refer to the numbers 13, 14, and 15 of our Frequently Asked Questions at the previously given link. NIST does not have any further information to add to these responses. NIST firmly stands behind its investigation results. The body of evidence still overwhelmingly leads to the following scenarios:

• WTC 1 and 2 collapsed because aircraft impact damage and debris dislodged fireproofing from critical steel components, jet fuel-initiated fires burned very hot for long duration when fet by debris and office materials, and the heat eventually weakened the exposed steel until it lost integrity and led to a global failure; and

* WTC 7 collapsed because damage caused by debris from the falling WTC 1 ignited fires on multiple floors and the heat expanded and dislodged a beam connecting a key perimeter column to bo a long-span central beam and a critical internal support column, and the column’s failure set off a chain reaction of failures across the building’s steel infrastructure.

Thank you for your interest in the NIST WTC investigation.

William Grosshandler
Deputy Director for Building and Fire Research
Engineering Laboratory, NIST

If anyone out there would like to respond to NIST based on a careful study of the sections referred to, please feel free. 

The vast body of evidence..

The reply from Mr. Grosshandler made me laugh. I may write a letter to him at some point. Thank you for your effort Mr. Hagen.

Had men never pointed a telescope skyward....

The body of evidence still overwhelmingly leads to the Sun revolving around Earth.