Can we do that here?
Only thing that i have found so far is a plausible but weak explanation of the collapse of the twin towers mainly due to the intense heat of the burning jet fuel. i want more details.
i would also ike to see a realistic explanation about the tons of cement and/or asbestos dust still in the air over 24 hours after this tragedy.
[Edited by bibliophage on 09-13-2001 at 01:22 AM]
As I understand it, One and Two World Trade Center buildings (the Twin Towers) had a “tubular” support system. That is, the main support of the building was the outer walls.
With that support cut 20-70% as it was after both plane collisions, the support was shifted to the internal steel supports. These would’ve held up the upper sections if it had just been the initial crash damage. The fires were fatal factor: they weakened the steel until they could no longer support the upper levels.
The remaining support in the building couldn’t handle the combined weight of the upper sections and the momentum it had gained falling. So the buildings collapsed floor by floor from the top down.
That’s really all it needs to bring the building down. I started a thread in GQ asking about this, and got quite a bit of information. You might want to check it out (sorry, don’t have the link).
Since this has been discussed so recently, I’ll close this thread and direct any further comments on this subject to the other one, Would a plane crash be enough to take out a WTC tower?
bibliophage
moderator GQ
I’ve decided the asbestos dust question is too important to just close this thread, so I retitled the thread and bolded the unanswered question. There are several questions here: How long will the dust linger, and how dangerous is it, etc.
Ever see the old depictions of a blacksmith at work, hammering iron into shape with tongs and an anvil?
The Smith heats the iron to make it soft, so it can be molded and shaped. I’ve done it myself. If the steel is “only” orange-hot, far lower in temperature than it’s “melting” point as several commentators have used, I can grab a one-inch square steel bar with plain shop pliers and bend it almost double by hand.
The planes carried tons of jet fuel, which burns somewhat slower than gasoline, jet fuel which puddled on floors and just sat there and burned. Add the furniture, wiring, walls, carpeting and other flammables, and I’m quite sure that many sections of steel saw temperatures well in excess of 1,500 degrees, for upwards of an hour.
Add to that the fact that, according to one site I read today, each floor weighed some six million pounds, and there were what, another thirty floors above the impact points?
Combine the two: Heat the steel, the primary load-bearing structural member of the tower, to the point where it becomes soft and almost plastic, and sheer weight will do the rest. As it began to collapse, the simple momentum of hundreds of thousands of tons of steel and concrete slamming down on each successive layer… well, that’s far more than the building was designed to withstand.
NO building COULD have withstood that.
As for the dust, well, there’s two buildings’ worth of concrete that have been pulverized… That undoubtedly created an enormous quantity of dust, that is simply kicked up and carried by the wind. I saw the news bits showing the office paperwork swirling in the winds… the same wind keeps stirring up the dust, helped along, unfortunately, by the constant activity. Right now, crews are shifting and shoveling, clearing paths through the rubble, searching for survivors or bodies…
Concrete dust, as far as I know, is no worse than “normal” dirt and dust. In large quantities, it can clog the alveoli in the lungs, but I don’t know of any long-term effects.
Dust masks are definitely recommended anyway.
Asbestos is only hazardous in small, breathable particulates- over time, it causes asbestosis, a lung disease, and it’s been linked to lung cancer. So here, definitely, wear a mask if you can, a wet rag if you have no other choice.
However, being built in the early seventies’, I don’t know how much asbestos the WT Centers contained. Wasn’t it being phased out of use at that point?
The only information I have on the asbestos is hearing a news reporter say that water was being used to wash concrete and asbestos off survivors. WTC was constructed in the late 60’s, so some asbestos could have been used in the construction.
The dust appears to be primarily concrete dust, though I’m sure it’s mixed with asbestos, ash, and crushed wall-board. Since reports are now saying there’s around 200 tons of debris from the two towers, I’m sure that helps explain why there’s a lot of dust.
Why is it still in the air? IANAS, but keep in mind that parts of the towers and some the surrounding buildings are still collapsing. Each time that happens, more dust is put into the air. Also, with the shifting of debris, dust is stirred up and driven back into the air.
Asbestos dust that is a hazard to humans is in the micron-size range. So, this stuff can stay airborne for a LONG time. Dilution will eventually get rid of it. Until then, there is a potential health hazard in the area but I have no idea how much of a hazard there is because I don’t know how much asbestos was in those buildings (presumeably a lot) and how much of that was friable (able to break apart into the micron sized fibers…some fraction of the overall asbestos content of the building) and damaged (presumably most of it…although much of the asbestos will be locked up in floor tiles, etc.).
Asbestos can lead to chronic lung diseases (asbestosis, cancer), but AFAIK, concrete dust is more of a short-term irritant (although maybe it can worsen other respiratory conditions?). Your lungs can’t really clean out asbestos because the milled fibers are spear-shaped and stay lodged in cell walls.
This was posted on a bulletin board hosted by my professional assocations, the International Facility Management Association:
“Without question, the collapse of the towers and adjacent buildings clearly released harmful contaminants into the air. These contaminants will have migrated into adjacent buildings, as well as buildings miles away.”
He doesn’t spell it out, but the contaminants will be more than just asbestos. Concrete dust itself is harmful in large quantities; it can coat the lungs and cause respitory infections.
It’s possible that lighting ballasts may have contained PCBs, depending upon their date of manufacture. This was a problem after the Meridian Bank building fire in Philadelphia.
Other possible contaminants might be fiberglass, mercury (from thermostats), airplane fuel, sewage, and human blood.
As a lawyer who has worked on asbestos litigation in New York City, I’m pretty sure I have heard that various asbestos materials were used in the construction of the World Trade Center.
How much, I don’t know, since all kinds of things have been made with asbestos at one time or another.
There is controversy over how much asbestos it takes to cause lung cancer, mesothelioma, asbestosis, etc., but keep in mind that most asbestos claimants are sailors, shipyard workers, miners, electricians, auto mechanics, and other tradesmen who were exposed regularly for a long period of time.
That said, I would still steer clear of downtown manhattan, as well as areas downwind (i.e. Brooklyn), for a while if possible.
IAAL. My law firm represents thousands of asbestos plaintiffs. We just finished a trial yesterday.
In my personal opinion there is no real health hazard. Classical pulmonary asbestosis requires far more exposure – years – than what you see here. Lung/GI cancer requires less exposure than pulmonary asbestosis but still not even a possibility here. Mesothelioma (an extremely rare form of lung cancer) is said by some experts to be capable of being produced by small exposures but even that is subject to debate. In short, while asbestos isn’t good for you under any circumstances, IMHO there is no real threat here under these circumstances. Defense lawyers would probably have even a stronger opinion on the subject.
Actual amount of asbestos in the buildings is unclear. apparantly 3000 trusses between floors 9 and 37 were coated with hundreds of tons of cement/asbestos slurry, before the action was stopped by unions and industrial hygiensts. Some of this was removed in subsequent renovations, but there is still untold quantities in things like pipe insulation and ceiling tiles. Some dust samples so far at the site have up to 4% asbestos.
To follow up on the last post:
Most asbestos will be from fireproofing for the steel girders – a spray-on insulation called Monokote 3 manufactured by W.R. Grace, as I have been told in other litigation. IIRC Monokote was about 10% asbestos by weight. Also there will probably be a fair amount of pipe covering insulation – perhaps 10-40% asbestos by weight.
OSHA/EPA banned asbestos (this is a generalization, of course) in 1972-1974 time period and they actually switched to asbestos-free materials during the construction of the second tower, I believe.
As a defense lawyer doing some asbestos defense (though only a bit; it is a very small fraction of my firm’s business), I would agree with JOHNW.
Some facts, summarized and generalized greatly:
Asbestos was used for years in insulation, building materials, and friction-producing parts (like, say, brake pads) because it is especially resistant to burning. For a long time it was considered quite the whiz-bang material because it is essentially fire proof. As such, in addition to whatever primary function it performed (like insulating) it provided protection against fire. Of course, this was before the long-term health effect were known.
It is now known that asbestos fibers, once broken up into particles, become easily suspended in the air and remain there for a long period of time. They are then inhaled by whomever happens to be unfortunate enough to be nearby. Exposure to asbestos can cause thickening of the lung tissues, varying degrees of resultant disease and breathing difficulties, and even in some cases a particularly nasty type of cancer. Diseases or disorders linked to asbestos generally do not manifest until some years after exposure (in some cases up to forty years), and the likelihood of developing an asbestos-related problem is directly corrolated to the length or frequency of exposure. (In other words, the more you breathe, the more likely you will eventually get sick.)
Since the period between exposure and disease development is so long, and since it is unknown how little asbestos can trigger disease (beyond the obvious general conclusion that less is better and more is worse), people working around asbestos (including asbestos removers) take extraordinary precautions to avoid breathing asbestos-laden dust. Of course, that’s an option the victims and rescue workers did not have. I would agree with JOHN that it is extremely unlikely that workers would develop problems from a single instance of exposure, but the truth is it may well be years before we know.
rundogrun– do you have an online cite for your statement about what portion of the building contains asbestos? (I’m not challenging you, but as an environmental scientist I have some interest in this!) Thanks.
Just read it this morning. Here you go…
My practice long ago included defending asbestos cases. And none of the Plaintiff’s lawyers would admit the above. Asbestosis, that is scarring of the lung tissue by the sharp little fibers, was thought to be caused by heavy long term exposure, such as shipyard insulators in WWII would experience: it looked like a snow storm every day. Some, not all of these people got asbestosis, which eventually destroyed the elasticity of the lungs years later. People who smoke and had significant asbestos exposure had a much higher chance of suffering from various cancers (lung, thoat were common) than people with only one of those risk factors, this synergistic correlation was on the order of 30 times higher than someone without either risk factor. These cancers, if caught early, were sometimes treatable. Mesothelioma is a very rare cancer of the lining of the lungs (pleural) or the lining of the stomach cavity (peritoneal). By the time I moved on in my career, there were only rumors of future effective treatments, it was always fatal in short order and an awful way to go. 80% of mesothelimomas were associated with asbestos exposure and the claim by the plaintiff’s was that one fiber could cause it. (Lot’s more people hit by lightening here, so no one get nervous, this is a very, very rare disease). During the 1950s there was a patented cigarette filter, the Kent Micronite, that used crocidilite, the most dangerous form of asbestos, and many mesotheliomas have been associated with that cigarette, of which billions were made.
Asbestos, by the way, describes the quality of a number of mineral fibers (five kinds I think), and is not itself properly a mineral.