THE MEXICO CITY EXPLOSION OF

1984

Nick ChumoAddy Hellebusch

Matt KelleyChris 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 explosions

15 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?