Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
InspectAPedia ® Home
ENVIRONMENTAL HAZARDS - INSPECT, TEST, REMEDY
ACCURACY vs PRECISION of MEASUREMENTS
AIR CLEANER PURIFIER TYPES
AIR FILTER EFFICIENCY
AIR FILTERING STRATEGIES
AIR FILTERING CONTINUOUS FAN OPERATION
AIR FLOW MEASUREMENT CFM
AIR HANDLER / BLOWER UNITS
AIR LEAK DETECTION TOOLS
AIR POLLUTANTS, COMMON INDOOR
Air Quality Improvement Strategies
AIR SEALING STRATEGIES
AIR TEST FOR MOLD: ACCURACY
AIR TEST SAMPLING CASSETTE STUDY
AIRBORNE MOLD COUNT NUMBER GUIDE
ALLERGEN TESTS for BUILDINGS
ALLERGY TESTS for PEOPLE
ALLERGY TEST ACCURACY
ANIMAL ALLERGENS / PET DANDER
ANIMAL ENTRY POINTS in BUILDINGS
ANIMAL or URINE ODOR SOURCE DETECTION
ASBESTOS CLEANUP COMPANIES
ASBESTOS IDENTIFICATION IN BUILDINGS
ASBESTOS LIST of PRODUCTS
ASBESTOS MATERIAL REGULATIONS
ASBESTOS PHOTO GUIDE to Materials
ASBESTOS REMOVAL CERTIFICATIONS
ASBESTOS REMOVAL GUIDE, FLOORING
ASBESTOS REMOVAL, Wetting Guidelines
ASBESTOS RISK ASSESSMENT
ASBESTOS TESTING LAB LIST
ASBESTOS UNDER the MICROSCOPE
ATTORNEYS and EXPERT WITNESSES
BACKDRAFTING HEATING EQUIPMENT
BIBLIOGAPHY for ENVIRONMENTAL HEALTH, MOLD, IAQ
BIOGAS PRODUCTION & USE
BOD WASTEWATER TEST
BLOWER DOORS & AIR INFILTRATION
BLUE vs YELLOW COMBUSTION FLAMES
BOOKSTORE - ENVIRONMENTAL
BUILDING SAFETY HAZARDS GUIDE
CACTUS FUNGI / MOLD
Cadmium in the home
CAR MOLD CONTAMINATION
CARBON DIOXIDE - CO2
CARBON MONOXIDE - CO
Carbon Nanotube Hazards
CARPET DUST IDENTIFICATION
CARPET MOLD CONTAMINATION
CARPET TEST PROCEDURE
CARPETING & INDOOR AIR QUALITY
CAT DANDER in buildings
CEILING PAINT TEXTURED ASBESTOS
CEILING TILES, ASBESTOS
CRLL PHONE Radiation Hazards
CERAMIC TILE, ASBESTOS in?
CHIMNEY INSPECTION DIAGNOSIS REPAIR
COMBUSTION PRODUCTS & IAQ
CONDENSATION or SWEATING PIPES, TANKS
CHINESE DRYWALL HAZARDS
CHEMICAL CONTAMINANTS in WATER
CHLORINE IN DRINKING WATER
CHLORINE in WATER, HOW TO TEST FOR
CHLORINE IN SEPTIC WASTEWATER
COMBUSTION GASES & PARTICLE HAZARDS
CONDENSATION or SWEATING PIPES, TANKS
CPSC Indoor Air Pollution Book Online Copy
DIRECTORY of MOLD / ENVIRONMENTAL EXPERTS
DIRT FLOOR MOLD CONTAMINATION
DISINFECTANTS & SANITIZERS, SOURCES
DISINFECTING BUILDINGS with BLEACH
DRYWALL MOLD TESTING
DRAFT HOODS - gas fired
DRAFT MEASUREMENT, CHIMNEYS & FLUES
DRAFT REGULATORS, DAMPERS, BOOSTERS
Diethylstilbestrol - DES
DUCT SYSTEM & DUCT DEFECTS
DUST ANALYSIS for FIBERGLASS
DUST, HVAC CONTAMINATION STUDY
DUST SAMPLING PROCEDURE
ENVIRO-SCARE - PUBLIC FEAR CYCLES
EMF RF FIELD & FREQUENCY DEFINITIONS
EMERGENCY RESPONSE, IAQ, GAS, MOLD
EMF ELECTROMAGNETIC FIELDS & HUMAN EXPOSURE
EMF Levels of Cancer Risk
EMF MEASUREMENT INSTRUMENTS
EMF MEASUREMENT PROCEDURES
ENERGY SAVINGS in BUILDINGS
ENVIRO-SCARE - PUBLIC FEAR CYCLES
EXTERIORS of BUILDINGS
Fiberboard Insulation Sheathing Mold
FIBERGLASS INSULATION MOLD
FIBERGLASS PARTICLE CONTAMINATION TEST
Fireplaces & Woodstove Contaminants
FLAME COLOR, BLUE vs YELLOW COMBUSTION
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FLOODS IN BUILDINGS-mold
FLOOR DAMAGE DIAGNOSIS
FLOOR TILE ASBESTOS IDENTIFICATION
ASBESTOS FLOOR TILE IDENTIFICATION PHOTOS by YEAR
Formaldehyde Gas Hazard Reduction
GAS EXPOSURE EFFECTS, TOXIC
Carbon Dioxide - CO2
Carbon Monoxide - CO
METHANE GAS SOURCES
GAS DETECTION INSTRUMENTS
GAS EXPOSURE LIMITS & STANDARDS
TOXIC GAS EXPOSURE EFFECTS
TOXIC GAS TEST PROCEDURES
GLARE, Sunlight/Lighting Control
Goodman HTPV RECALL
HEATING SYSTEM INSPECTION
HEATING OIL EXPOSURE HAZARDS, LIMITS
HOME HEATING SAFETY
HUMIDITY CONTROL & TARGETS INDOORS
Indoor Air Pollution Book Online CPSC
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
INSULATION INSPECTION & IMPROVEMENT
INSULATION IDENTIFICATION GUIDE
ASBESTOS INSULATION on PIPES
INSULATION INSPECTION & IMPROVEMENT
INSULATION IDENTIFICATION GUIDE
INSULATION, UFFI UREA FORMALDEHYDE FOAM
LAB PROCEDURES MICROSCOPE TECHNIQUES
This website article presents photographs of dust particles from the World Trade Center Collapse as an aid in the identification of the nature and composition of typical particles found in dust from the World Trade Center Collapse. The WTC dust particles shown above and in these photographs were examined in our forensic microscopy laboratory and were a portion of physical samples of dust collected from New York City building window sills at the 9/11/01 site shortly after the attack. Digital photographs were made at magnifications ranging from 300x to 1920x and using both transmitted light and polarized light microscopy in our forensic laboratory in Poughkeepsie, NY.
Green links show where you are. © Copyright 2014 InspectApedia.com, All Rights Reserved.
The concerns for public health and simple public anxiety concerning the contents of the dust created by the World Trade Center Collapse deserve thoughtful attention. However no scientific inquiry regarding this material should proceed without remembering to treat the substance and its implications with utmost respect, as is our intention here.
The purpose of these microphotographs is to aid researchers in recognizing typical World Trade Center Collapse Dust particles when they may be present in other environmental samples. Small amounts of dust from these samples can be provided to other research scientists on request. The micro-photographs here investigate the contents and physical appearance of the dust particles created by the September 11, 2001 World Trade Center collapse following the terrorist attack on that date. Particles in dust can be identified, in many instances, by forensic microscopy.
While this work was begun in September 2001, the resulting photos taken through the microscope were not displayed until development of this public information page in 2006. Also see Asbestos: How to find and recognize asbestos in Buildings and Asbestos HVAC Ducts and Flues.
Microscopic Photos of Dust Particles from World Trade Center Collapse
Typical particles in this material include fiberglass, slag wool, asbestos, paper, cotton and other fabric fibers, plastic fragments and droplets, wood. Some photos also show starch granules, recognizable in polarized light. The dust from the WTC collapse does not include identifiable microscopically identifiable organic particles. Particle sizes range from large, perhaps 20 x 120 u (typically fiberglass) to sub-micron particulates. Magnification in these photos ranges from 300x to 1920x.
Experts report other contents in this dust including "microscopic traces of nearly every element - chromium, magnesium, manganese, aluminum, barium, titanium, and lead." [N.Y. Times, "What Happened to That Cloud of Dust", Pg. B1, B7, 11/2/2006]. The Times article reported on work by Paul J. Lioy, who mapped the dust and gas plume movement following the attack and collapse of the buildings. Lioy reported that volatiles were also present including components of jet fuel. Volatiles would have been present in gaseous form not as particulates.
By May 2006, increasing media reports indicate very serious health effects from exposure to high levels of this dust, including apparent fatalities and significant loss of lung function (pulmonary aging). By January 2007 these effects were well established in public media reports such as articles in the New York Times and various health journals.
Click on the image or the link to see an enlargement of each forensic microscopic photograph of the dust from the world trade center collapse
Frequently Asked Questions (FAQs)
Fequently-Asked Questions (FAQs) or other questions & remarks about dust and particulates from the 9/11 World Trade Center Collapse
Question: thermate reported in some WTC dust samples
I found unburned thermate in the samples send to me. Didn't you find any? - Max Christiansen, 12/13/11
Reply: the Thermate/Thermite Conspiracy Theory of the World Trade Center Airplane Attack of 2001
No Max. I did not find thermate in my WTC dust samples collected nearby horizontal surfaces at the WTC disaster site. Nor do I claim to have performed technically exhaustive tests on the world trade center dust. Our lab retains a small amount of dust from this terrible event and we have occasionally agreed to make samples available for further testing by qualified experts.
The conspiracy assertions behind your elegantly brief question deserve a longer reply.
Although I've heard about the thermite/thermate theory and have seen a paper published on that topic, I have not followed details of the thermite / thermate WTC conspiracy theory.
Have you documented and had peer reviewed your own lab procedures and conclusions? And given the minute amounts of material actually submitted to testing and the sensitive nature of such tests, are there other possible explanations for chemical signatures that might be found in particle testing?
No responsible forensic analyst should claim that a given particle analysis is technically exhaustive, nor that there could not be confounding data, or even contaminants in a sample. At an event such as the 9/11 disaster there might be confounding heat, fire, sources of materials from various building and aircraft components, and other chemistry that could contribute to later tests finding particle results resembling a variety of substances that do not accurately characterize the dust, including tests suggesting the presence of thermite.
Another World Trade Center Attack Conspiracy Theory
Shortly after the September 11 disaster, a Moroccan acquaintance espoused a different theory to explain the airplane crashes that led to collapse of the towers. He was convinced that Jews planned and executed the aircraft flights that crashed the World Trade Center, damaged the U.S. Pentagon, and crashed a third aircraft into the ground in Pennsylvania. His view was that Jews planned these events in order to make trouble for the Arab world.
His remarkable proof of that Jewish conspiracy argument was his assertion that on 11 September 2001, all of the Jews who worked in the WTC knew of the pending disaster and that they all stayed away from work on that date.
How could one explain how anyone could actually believe such an absurd theory?
Excusing deliberate pandering as the source of the Jewish WTC conspiracy theory, (not something I'd associate with my acquaintance, a University professor in Rabat) it may help to understand some of the cultural differences between American Jews living in New York City and Moroccan muslims living in Rabat, Morocco.
My acquaintance lives in Rabat, Morocco, in a community where religious and cultural views are much more homogeneous than in the U.S., and where news travels quickly by word of mouth throughout the (comparatively much smaller) community, and finally, where on a given religious holiday nearly everyone is doing the same thing at the same time.
Based on his mistaken assumption that people and communities in the U.S. (a country he does not know well) could not be very different from his own, my acquaintance could not imagine that, as I explained, not only do American Jews not blow up their neighbors and their cities, in New York City, Jewish people working in the huge population of the World Trade Center would not even know one another, much less be in secret mutual contact.
There is no secret Jewish telegraph service that links up American Jews nor is there anything like the same conformity of opinion, political or religious, as we see in some other areas of the world such as my acquaintance's own Rabat, Morocco.
Still more significant, among the thousands of Jewish people who worked daily in the World Trade Center, all of whom, by my acquaintance's theory had to be notified to stay at home on September 11th, no conspiracist of any persuasion could possibly count on thousands other people, Americans, Jews, or of any other label to remain quiet, nor to take no action to prevent such a calumny.
Engineering Explanations for the WTC Collapse
Your analysis for thermate in World Trade Center collapse dust, I infer, is in response to several popular articles indicating that some scientists have reported finding evidence of explosives in WTC dust. "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." - Wikipedia web search 12/13/11. [An incendiary grenade is intended to light a fire, not to blow out structural columns.]
I am not a building collapse nor explosives expert, though our McCrone research training does include some microscopy, PLM, and microchemical methods for identifying certain particles of explosives.
But there are other more direct engineering explanations for the collapse of the 9/11/01 World Trade Center Towers   than a conspiracy to place a precisely coordinated and precisely placed collection of incendiary grenades throughout the buildings. I personally witnessed the events of 9/11/01. I was close enough to see the second aircraft strike the WTC, to watch with horror as I saw the first falling tower first tip to one side, then straighten and fall straight down, collapsing floor after floor below the original point of origin. And of course experts have pored over films and made other studies of the event.
Paraphrasing some of the more engineering-based articles on the Trade Center collapse, the structures were not designed to withstand the forces generated by the collapse of all or a significant part of an individual floor level. As the first floor level collapsed the impact broke the structure below, and so on.
Quoting from S.W. Banovic, et als:
Quoting from Eagar & Musso:
Occam's Razor and WTC Collapse Conspiracies
Having worked with a great many people who've suffered illness and tragedy in my own forensic work, I understand well the difficulty of accepting very painful catastrophes, and the inclination to look for greater, more complex conspiracies or other theories that might explain a disaster.
We will continue to monitor research on WTC dust with interest. The principle of Occam's Razor suggests that when there are two competing explanations for an event, one simple and direct, and the other complex and difficult, usually the first, simpler explanation is correct.
We are dedicated to making our information as accurate, complete, useful, and unbiased as possible: we very much welcome critique, questions, or content suggestions for our web articles. Working together and exchanging information makes us better informed than any individual can be working alone.
InspectAPedia is an independent publisher of building, environmental, and forensic inspection, diagnosis, and repair information provided free to the public - we have no business nor financial connection with any manufacturer or service provider discussed at our website.
Respectfully, Daniel Friedman
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website
HTML Comment Box is loading comments...
Technical Reviewers & References
Allergies, Allergens, Allergy Testing in Buildings - References & Products
Mold Contamination Testing, Cleanup, Prevention: references & products
OTHER IAQ ISSUES: How To Find and Address Other Indoor Air or Indoor Environment Contaminants Besides Mold
Mold or allergens may not be the only or even the main indoor environmental contaminant. Don't let media attention to mold cause so much enviro-scare fear that other, possibly more urgent hazards go un-addressed.