The Mexico City disaster occurred in a very significant year for the chemical industry, as two of the worst industrial disasters were recorded in the space of hardly a month. The Mexico City Disaster, which occurred on 19th November, 1984, claimed over 500 lives, and left around 7000 people injured. It was followed by the even more gruesome Bhopal Disaster, on 3rd December, which left over 3000 people dead, and affected over 2,00,000 (though the latter was not a fire accident). These incidents once again reminded the world of the dangerous properties of the various chemicals that were handled in industries so close to human habitation.

This incident occurred at the PEMEX plant, whose main activity was to take LPG from nearby Refineries through pipeline, and loading the same into road tankers and railway wagons. Most of the premises consisted of storage tanks in the form of spheres and bullets, and at the time of the incident, had approximately approximately 6500 tonnes of LPG in the premises. Adjacent to it were 2 LPG bottling plants, engaged in the activity of bottling domestic LPG cylinders. On the day of the incident, a leakage occurred in the pipeline supplying LPG to the plant from a Refinery, almost 400 kms away. At around 5.35 a.m. on 19th November a drop in pressure was noticed by the control room and a pipeline pumping station, but the operators were unable to determine that the cause was the rupturing of an 8" pipe connecting one of the spheres to a series of cylinders. The release of LPG continued for between 5 and 10 minutes, resulting in the formation of a flammable cloud approximately 2m high and covering an area of 200m by 150m. As the vapours traveled downwind, they got ignited from a flare tower, giving rise to a vapour cloud explosion, which in turn ignited a small number of small fires, within and outside the premises. The original leak now had a simpinging on one of the LPG spheres. This of the sphere after about 15 minutes, and the formation of a fireball, approximately 300 metres in diameter. Within the next 90 minutes or so, almost eight other ruptures were recorded, and the fires raged for almost another 20 hours before they were brought under control. Some of the explosions were powerful enough to be recorded on a seismograph at the University of Mexico As the neighbouring LPG bottling plants were also involved in the large conflagration, a large number of cylinders also ruptured, flying off in various directions and further complicating the situation. In the final analysis, besides those dead and injured, almost 39,000 people were affected and had to be evacuated because of the incident.

Mexico City Disaster - effects and consequent safety upgradation

This incident and the Bhopal disaster took place in the not so developed countries, and it became clear that the effects of industrial accidents would be further compounded due to the typical problems of such countries - dense populations, poor urban planning, weak legislation and implementation. These countries realised the consequences of the fallout of industrial activity, and took the cue to set up stricter legislation and work practices. Safety issues came to be treated with much greater concern and seriousness in developing countries after these two disasters.