THE MEXICO CITY EXPLOSION OF

1984

Nick Chumo

Addy Hellebusch

Matt Kelley

Chris Williams

Introduction

November 19, 1984 San Juanico; a suburb of Mexico City 20 km outside of Mexico City 40,000 residents Low income families Homes as close as 130m to plant

Plant and “Process”

Pemex State Oil Company Storage & Distribution facility for liquefied

petroleum gas (LPG)LPG comes in from 3 different refineries

54 LPG storage tanks- 16,000m3

Daily throughput- 5,000m3

6 large spherical tanks○ 2 largest holding 2400m3

48 smaller tanks of various sizes Built to API Standards

Right Before Explosion

Being filled from a refinery 400km away 11,000m3 LPG on site Fall in pressure

The cause of the pressure drop was unidentified

no one initiated emergency shutdown

Pemex Before

Pemex After

What Happened

One of the deadliest industrial disasters in world history

The initial vapor cloud explosion was the start of a chain reaction of explosions

There were 19 explosions15 cylindrical tanksThe 4 smaller spheres

Many of the explosions were BLEVEsThe relative times can be told from seismic

readings

What Happened cont.

Most of the damage to the city was from fires not the explosions

Fragments from the tanks reached over 1,200 m awayThe fragments were hot enough to start firesPieces trailed raining LPG as they flew

A concentrated rescue effort was put into action with 3000 rescuers on site

200 firefighters risked their lives

Accident Timeline 5:30am Rupture of 8 in. pipe; Pressure drop in

control room 5:40am Ignition of gas cloud; Violent

combustion and high flame 5:45am First explosion on seismograph, a

BLEVE; Fire department called 5:46am Second BLEVE, one of the

most violent 6:00am Police alerted and civilian

traffic stopped 6:30am Traffic chaos

Accident Timeline cont. 7:01am Last explosion on

seismograph, a BLEVE 7:30am Continuing tank explosions 8-10:00amRescue work at its height 11:00am Last tank explosion 12-6:00pm Rescue work continues 11:00pm Flames extinguished on last

large sphere 10:00am Last fires put out (next day)

Root Causes

Official cause of rupture is unknown One report cited

Overfilled tank caused the inlet line to rupture

Failure of relief valve

Results

500-600 deaths; 300+ never identified 5000-7000 severe injuries 10,000-60,000 people made homeless 31 million dollars of damages Destruction of 1/3 of the LPG supply to

Mexico City

Results

Results

Future Preventions

Timely inspections Maintain industrial standards Better maintenance Effective operator training Housing appropriate

distance away

Future Preventions cont.

Proper layout of large LPG storages

Gas detection and emergency isolation

Water system failures Extra water hydrants in the streets Planned evacuation routes

Summary

This deadly disaster struck the morning of November 19, 1984

Lasted from 5:30am till 10:00am the next day

Left hundreds dead and thousands injured and homeless

Many lessons can be learned from the tragedy

QUESTIONS?