1992 explosion in Guadalajara

The 1992 explosion in Guadalajara, Mexico's second largest city, took place on April 22, 1992 in the downtown district of Analco. Numerous gasoline explosions in the sewer system over four hours destroyed kilometers of streets. [http://www.drj.com/drworld/content/w2_028.htm James Dugal: “Guadalajara Gas Explosion Disaster” in Disaster Recovery Journal.] Gante Street was the most damaged. Officially, 206 people were killed, nearly 500 injured and 15,000 were left homeless. The estimated monetary damage ranges between $300 million and $1 billion. The affected areas can be recognized by the more modern architecture in the areas that were destroyed. [http://www-tech.mit.edu/V112/N22/mexico.22w.html Peter Eisner: “Nine officials charged in sewer-line explosions case.” The Tech. April 28, 1992.]

Three days before the explosion, residents started complaining of a strong gasoline-like smell coming from the sewers. Some residents even found gasoline coming out of their water pipes. City workers were dispatched to check the sewers and found dangerously high levels of gasoline fumes. Unfortunately, the city mayor did not feel it was necessary to evacuate the city because he felt that there was no risk for an explosion. [http://www.semp.us/publications/biot_reader.php?BiotID=356 SEMP Biot #356 "The Guadalajara 1992 Sewer Gas Explosion Disaster" May 03, 2006.]

Aftermath

An investigation into the disaster found that there were two precipitating causes:

* New water pipes, made of zinc-coated copper, were built too close to an existing steel gasoline pipeline. The underground humidity caused these metals to create an electrolytic reaction, which eventually caused the metal to corrode, creating a hole in the pipelines that caused gasoline to leak into the ground and into the main sewer pipe.

* The sewer pipe was recently rebuilt into a U-shape so that the city could expand their underground railway system. Usually sewers are built in a slope so that gravity helps move waste along. In order to get the U-shape to work, an inverted siphon was placed so that fluids could be pushed against gravity. The design was flawed, however. While liquids were successfully pumped through, gases were not, and gasoline fumes would build up.

A small spark was all that was needed to ignite the dangerous gases.

In the aftermath, city officials and corporations pointed fingers at each other. Some people initially thought a cooking oil manufacturing company was leaking hexane, a flammable liquid similar to gasoline, into the sewers, but this was later found to be erroneous. Numerous arrests were made in an attempt to indict those responsible for the blasts. [http://www1.umn.edu/humanrts/cases/17-03.html Legal documents pertaining to this case] Four Pemex officials were indicted and charged, on the basis of negligence. Ultimately, however, these people were cleared of all charges. [http://www.time.com/time/magazine/article/0,9171,975488,00.html News on Pemex indictment]

ee also

*National Geographic "Seconds From Disaster" episodes

References