Wednesday, July 24, 2013

Holy Shit, the Guadalajara Explosions!

Guadalajara Explosions of 1992


On April 18, 1992, residents of the Analco district in Guadalajara, Mexico started complaining to their local government that the streets smelled funny. The next day, plumes of white smoke were spotted coming out of storm drains and sewers, and the smell got worse. Some people were understandably confused when they turned on their faucets and were greeted not with the water of life, but with gasoline.

This was a bad thing.

Jar of Gasoline
Albeit convenient if you didn't feel like driving out of your way, I guess.

City workers were dispatched to investigate, and they reported dangerous levels of gas fumes in the sewers. Probably not enough to cause any damage, they insisted. So the mayor advised everyone to go about their business while the city worked out a solution to the smell and the very obviously tainted water supply. Because that's no big deal, right? What's the worse that could happen?

If you answered, "The whole goddamn city could blow the hell up," congratulations! You understand basic safety rules concerning gasoline. The City of Guadalajara, sadly, did not. No one was evacuated before the gas lines below the Analco district violently exploded. 11 times.

Guadalajara street after explosions
One would have sufficed, I'm sure.

The explosions utterly destroyed five miles of streets and up to a billion dollars' worth of property. That's on top of the 252 deaths, 500 injuries, and 15,000 people rendered homeless by the damage.

So how did this happen? Aside from gross negligence in the face of increasingly worrisome signs of a gas leak, how did the damn leak get there in the first place? Well, if you've ever experienced a water leak in an older house with mixed metals in the plumbing, you may already know the reason.

The water pipes in Guadalajara were relatively new, and the city didn't want to spend too much money putting them in. They opted for zinc-coated iron for the material, not taking into account the fact that, in order to save money on excavation, the new pipes were being installed right next to steel gasoline pipes. When you stick those two metals together, science happens!

Corroded Pipe
The kind of science you don't want on your water pipes or (especially) gas pipes.

Specifically, a chemical reaction that results in corrosion which, when water is added to mix, leads to even more corrosion. I don't think I need to tell you (especially since you already know the result) why all this corrosion right next to a gas pipe is bad news bears.

The moral of the story here is that plumbing is complicated, and can blow up not just your house, but an entire city district.

Holy shit.

5 comments:

  1. Yeah pretty goddamn terrible day for us who were there (I was visiting relatives for easter weekend and we lived 2 streets from Gante St, the first one to blow up). I had uncles who dug bodies and survivors out of the rubbles themselves because the government didnt do a damn thing but stand around and watch to "prevent looting". All the while blasts continue to rock that whole 20 block area of Analco. Cars and city busses flipped over and on top of buildings, bodies covered in dust hanging from telephone wires and trees, PEMEX (the state oil company) blaming the disaster on a....COOKING OIL FACTORY when it was apparent the leaks came from the Pemex plant pipelines down the street...the mass exodus of people (including us) into the countryside because we thought the whole damn city was going to explode from under us. When you walk down the street out and about you shouldnt worry about having the sidewalk and street explode from under you in a huge megafart which this ended up being (gasoline, methane gas from the sewers + a spark = hell on earth). The official toll was 200+ but I had relatives who saw bodies lined up in stadiums with numbers 700 and higher on them. Wouldnt be surprised if it was more than 1000 who died that day since the government likes to cover stuff up like this "Hm you smell gas in your drains. DONT WORRY!". Thanks for sharing this, this tragedy is largely forgotten and unknown outisde the streets of Analco and Guadalajara.

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    1. Thanks for your comment. It's great to get a perspective from someone who actually witnessed the event.

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  2. The cause of the 1992 Guadalajara pipe failure is commonly being attributed to corrosion, whereas the true cause was electrolytic erosion between the small steel water pipe and the much larger steel petroleum pipe which had been closely over-passed by the water pipe. The electrolysis current was being caused by D.C. ground-leakage from the adjacent Metro underground railway. Such ground-currents occur with every electric railway which uses Direct Current power via an overhead wire and earth-return rails. Any buried steel pipes passing anywhere near such a railway need to be protected, from erosion, by an impressed-current cathodic protection system. If they are not so protected, the pipes will suffer rapid electrolytic-erosion and drastic perforation, as happened in Guadalajara in 1992.
    If anyone should be blamed for the Guadalajara disaster, it is those organisations which installed the steel petroleum pipeline and the steel water pipe, for failing to impressed-current protect them.
    Although the method used to deal with the intersection of the sewer main and the Metro rail tunnel was not brilliant (i.e. use of a syphon configuration), the sewer's inability to drain away the accumulated gasoline was not the cause of the disaster, the passing of a pipeline conveying volatile flammable product (gasoline) through a heavily-populated area, and the failure to impressed-current protect this pipeline, were the true causes of the disaster.

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    1. Elecrolytic erosion is a type of corrosion. There is a thing called erosion corrosion, you know!

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  3. Can u explain the electrolytic reaction happened with chemical equations?

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