THE MEXICO CITY EXPLOSION OF 1984 Nick Chumo

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 130 m 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, 000 m 3 �Daily throughput- 5, 000 m 3 � 6 large spherical tanks ○ 2 largest holding 2400 m 3 � 48 smaller tanks of various sizes � Built to API Standards

Right Before Explosion � Being filled from a refinery 400 km away � 11, 000 m 3 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 explosions � 15 cylindrical tanks �The 4 smaller spheres � Many of the explosions were BLEVEs �The 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 away �The fragments were hot enough to start fires �Pieces 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: 30 am � 5: 45 am � 5: 46 am � 6: 00 am � 6: 30 am Rupture of 8 in. pipe; Pressure drop in control room Ignition of gas cloud; Violent combustion and high flame First explosion on seismograph, a BLEVE; Fire department called Second BLEVE, one of the most violent Police alerted and civilian traffic stopped Traffic chaos

Accident Timeline cont. Last explosion on seismograph, a BLEVE � 7: 30 am Continuing tank explosions � 8 -10: 00 am Rescue work at its height � 11: 00 am Last tank explosion � 12 -6: 00 pm Rescue work continues � 11: 00 pm Flames extinguished on last large sphere � 10: 00 am Last fires put out (next day) � 7: 01 am

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: 30 am till 10: 00 am the next day � Left hundreds dead and thousands injured and homeless � Many lessons can be learned from the tragedy

QUESTIONS ?