Wednesday, October 24, 2007

Shit Bombs: A Cross-country Comparison

Shit Bomb-type blasts like the recent one in Glorietta are relatively rare, but have been known to happen before. Here is an account of one such event that took place in Ghana back in May 2004:

"The explosion which had the near force of a volcanic eruption was so loud that it was able to throw concrete, dust and human excrement (faeces) into the air, while residents ran for dear life from the force of the methane gas. The Pig Farm public latrine is one of a cluster of four toilets in the area. Six men were attending to nature’s call in the facility when it blasted. Eye witnesses say the blast caused the emission of strong fumes into the air."
The above description is instructive in that it englightens us on the cross-country variations of this kind of event. While the noise and force of the explosion are common elements to be found in both the Ghana and Glorietta deflagrations, there are also marked differences in terms of the composition of the blast debris and the fumes emitted.

What accounts for the relative lack of fecal matter found in the Glorietta incident compared to the Ghana-type event? I believe that the determining factor is cultural. While Ghanians presumably have a more up-front disposition as demonstrated by the relatively wide dispersal of their excrement, the typical Filipino with his well-known sense of "hiya" is more discreet. The resulting payload then embodies the character of its owners which explains why, in the course of the explosion, it chose to keep a low profile and stay in the basement lest it suffer undue embarrasment from public exposure.

Another obvious difference is in the nature of the fumes unleashed. Instead of the usual pozo negro smell that one would expect from a methane cloud, the Filipino shit bomb was characterized more by the smell of gunpowder. This can, of course, be attributed to hygienic practices, particularly the Filipino's penchant for regular brushing of teeth after every meal coupled with frequent washing of hair. As is well known, toothpaste and shampoo contain RDX, and the resulting build up of this explosive substance in the human body inevitably gets expelled into the sewage system. Seen in this light, the gunpowder smell can be easily accounted for.

For a more informative take on this topic, visit the opposing conjectures of Tounge-In-Anew who, for reasons of his own, still favors the bomb hypothesis, and DJB who prefers the apt-sounding deflagration hypothesis. Since these theories are mutually exclusive, it is safe to say that one will turn out to be full of shit.


Baldagyi Hatipoglu said...

very erudite title and especially sensitive conclusion! :p

cvj said...

Thanks. So far that Ghana tabloid reference is the only instance i can find in the Web of such a blast, and even that account sounds like a fake news item a-la The Onion. Even so, it does sound more realistic than the reports we are getting on the Glorietta blast.

Dominique said...

Hi, Chuck: was thinking about the exact same thing. Let me tell you what the next explanation will be: it wasn't methane, after all, it was urea. And urea is a component of fertilizers. And it can also be used to make bombs. wasn't a sh*t bomb, it was a p*ss bomb!

AdB said...

Geez! To have a shit explosion of that magnitude, there was evidently poor maintenance. Imagine those little beasts proliferating in the tank and exuding methane?


cvj said...

Hi Dom, i think that conjecture is also worth looking into :-)

Hi Anna, yeah. If true, the Ayalas have a lot of explaining to do.

Jego said...

Pucha. I had to do a double take. Good one.

There is always the sabotage angle. You dont need a bomb to set off a diesel-and-methane explosion if you leak the stuff into the poorly ventilated space first then engineer a spark. We're looking for someone with knowledge of chemistry, Gil Grissom.

Seriously, we can't rely in witness ' perceptions at this point. If CSI taught me anything, it's that eyewitness testimony is the least reliable piece of evidence. "Concentrate on what cannot lie." Or at least on evidence without imagination.

How to explain the lack of shit? If the explosion occurred above the septic tanks and not in it (fumes leaked into the poorly ventilated chamber from the tanks), you won't have shit. From what I gather, the force of the blast went straight up. No crater. The pozo negro wasnt breached.

cvj said...

Hi Jego, i agree with you on the need for evidence that doesn't require much imagination. The less Rube Goldberg-ish the explanation is, the more believable it is.

Right now, what i understand from the process is that the methane generated from the septic tank migrated to the vicinity of the diesel tank which then suffered structural failure at a localized weak spot and ejected blast waves which propagated upward like a cannon.

The above scenario leaves the question of why did the diesel tank fail at that spot. Why the new hole? Why was the blast wave not ejected the same way the methane gas came into the tank?

cvj said...
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tonio said...

hello sir,

RDX is used in toothpaste? a use government site mentions this:

RDX is used in fireworks, demolition blocks, as a heating fuel for food rations, and as an occasional rodenticide

but toothpaste?

cvj said...

hi tonio...and shampoo according to the 'bomb experts'.

Jego said...

...and PVC pipes, they said.

Anyway, this is the reason I think the deflagration theory is at least plausible: Several years ago, for New Year's Day, we made this contraption that consists of several beer cans with tops and bottoms removed, held together with duct tape, into a tube of about a meter and a half long. At one end of the tube, instead of removing the bottom from a can, we punched several small holes. Then we got another can with no top, and punched one hole in it and stuck that to the end of the tube over the one with several holes.

The way it works is we squirt a few drops of lighter fluid in hole at the end of the tube, then shake the tube. This fills the bottom can with a highly volatile vapor. Then we put the bottom hole near a flame, usually a candle, then BANG! The explosion was tremendous and the force only came out of one end of the tube; the one on the other end. Now this bottom can with the vapor would be analogous to that poorly ventilated room in the basement with the diesel tank. The heat from the generators surrounding it would make the diesel more volatile it, and wouldve leaked out of a defective tank. The methane gas from the sewage system runs through that room and couldve leaked into the room as well.

The toy cannon we made had holes on both ends: the small one where we squirt the lighter fluid, and the big one where the force comes out. One would think that it had sufficient ventilation, and yet it explodes. The reason I guess is that methane and diesel fumes are heavier than air and would pool at the bottom. The vapor in the toy ignites using a flame, which has a lower temperature than an electrical spark.

Mythbusters verdict, therefore: Plausible. But like I said, sabotage could not be ruled out, but it would take a pretty sophisticated saboteur.

cvj said...

Hi Jego, in your experiment, you had to punch a hole on both ends. To make your analogy fit, that would mean that the diesel tank already had the bigger hole in the top rather than one that has been created by the force of the explosion. Also, a more faithful depiction of reality would have your lighter fluid vapor fill the entire room, unless what you're saying is that the cannon is the room.

Jego said...

Yes, something like that, I suppose; the cannon is the room. The rapidly expanding gases would look for the easiest path in which to escape, look for the path of least resistance. It turned out to be the concrete slab directly on top of the room. Debris from the concrete slab wouldve been launched upwards. If the walls were weaker than the ceiling, the blast wouldve gone out through the walls.

The diesel tank didnt have to have the big hole. Fumes could escape through the seams or seals if the tank were defective in design (I recall they were rectangular and not cylindrical?). I guess that would be analogous to the little holes punched in my beer can toy cannon. If there was indeed a big hole in the diesel tank, that couldve been caused when the vacuum created outside the tank during the explosion made the fumes inside the tank bust out of where the weakness in the diesel tank was, adding to the explosive effects. It would be interesting if they could determine whether there was a secondary explosion from the diesel fumes alone after the diesel and methane one milliseconds earlier.