1.
MOHIT SINGH
06116101413
CT(6TH SEM)
USCT

2.
CONTENT
 When and where?
 Before and after?
 What happened?(*)
 How it happened?(*)
 Result?
 Lessons learned?
 Future action?

3.
WHEN? WHERE?

4.
Introduction
 November 19, 1984
 San Juanico; a suburb of Mexico City
 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
 6 large spherical tanks
 48 smaller tanks of various sizes
 Built to API Standards

5.
Right Before Explosion
 Being filled from a refinery 400km away
 Fall in pressure
 The cause of the pressure drop was unidentified
 no one initiated emergency shutdown

6.
Pemex Before

7.
Pemex After

8.
WHAT HHAPPENED

9.
What Happened
 About 0530 hours, 8 inch feed pipe near the
vapor phase of Horton Sphere F-4 ruptured
causing release of LPG.
 Official cause of rupture is unknown .
 Release of LPG continued for 5-10 minutes.
 Gas cloud (200x150 m, height 2 m) found the flare
and got ignited at 0540 hours

10.
 The cloud caught fire over a large area, giving a
high flame and causing violent ground shock.
 Series of explosions followed as vessels suffered
BLEVE. 19 explosions over a period of one and
half hour.
 Numerous missiles generated by the bursting of
vessels. Many of these were large and traveled
far.

11.
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

12.
Accident Timeline cont.
 7:01am Last explosion on
seismograph, a BLEVE
 7:30am Continuing tank explosions
 8-10:00am Rescue 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)

13.
HOW?????

14.
Causes of Unsafe Acts and/or
Conditions
 Lack of : Experience , Training
 Poor Supervision
 Laziness
 Distractions
 Personal Pressures :
Your team playing tonight?
Problems at home?
 Human Errors : Forgetfulness

15.
Root Causes
 Official cause of rupture is unknown
 One report cited
 Overfilled tank caused the inlet line to
rupture
 Failure of relief valve

16.
Failings in Technical
Measures
 Plant Layout and positioning of vessels not proper.
 Emergency isolation means not available.
 The Terminal’s fire water system was disabled in
the initial blast. Also the water spray systems were
inadequate.
 The Plant had no gas detection system and
therefore when the emergency isolation was
initiated it was probably too late.
 The traffic chaos hindered the arrival of
emergency services.

17.
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

18.
Results

19.
Results

20.
Lessons Learned
 Old plant, too congested, poor
maintenance & poor operator training
were cited.
 Homes as close as 130m to plant.
Village should have been 1,500 meters
from terminal.
 Require many gas detectors and alarms.
 Emergency plan required

21.
FUTURE ACTION
????

22.
Future Preventions
 Timely inspections
 Maintain industrial standards
 Better maintenance
 Effective operator training
 Housing appropriate distance
away

23.
Future Preventions cont.
 Proper layout of large LPG
storages
 Gas detection and emergency
isolation
 Extra water hydrants in the
streets
 Planned evacuation routes

24.
“There is a saying in Tibetan, 'Tragedy
should be utilized as a source of
strength.'
No matter what sort of difficulties, how
painful experience is, if we lose our
hope, that's our real disaster.”
― Dalai Lama XIV

25.
References and links
 Arturson, G. (April 1987). "The tragedy of San
Juanico--the most severe LPG disaster in
history". Burns Incl Therm Inj. 13 (2): 87–102.
 Explosiones en San Juanico - YouTube video on
the disaster showing casualty response, burning
LPG spherical tanks, among other things
 PEMEX LPG Terminal, Mexico City, Mexico. 19th
November 1984 - Health and Safety Executive