The PEPCON Disaster
Group B08
Hamish Milne, Louise O’Donnell, Robyn Watt, Harry Walton
Abstract
This report will discuss and examine the engineering disaster that took place on May 4th, 1988 at the Pacific Engineering and Production Company of Nevada (PEPCON) at the chemical plant in Henderson Nevada. Specifically, it will discuss the history of the chemical plant, the disaster that occurred as well as analysing the causes and repercussions that followed afterwards.
Acknowledgements
A special recognition to Dr Donald Ballance for his useful advice and expertise throughout this assignment. His encouragement and support was greatly appreciated by all group members.
Contents of Report
Contents Page Number
List of Table ……………………………………..
List of Figures …………………………………….
Glossary of Terms ……………………………………..
Introduction ……………………………………..
Background History of PEPCON …………………………………….
The PEPCON Incident ……………………………………
Causes of Explosion …………………………………….
Reprecussions/
Improvements of Explosion ……………………………………..
Conclusions ……………………………………..
References ……………………………………..
List of Figures
Media image of the PEPCON plant exploding – see reference
Glossary of Terms
Term Description
Ammonium Perchlorate – Ammonium perchlorate is an inorganic compound with the formula NH₄ClO₄. It is a colourless or white solid that is soluble in water.
Drums – A storage vessel/tank
The Challenger Explosion – January 28th 1986, the NASA orbiter mission STS-51L and tenth flight of Space Shuttle Challenger broke apart 73 seconds into its flight, killing all seven crew members,
Fibre Glass – A common type of fibre reinforced plastic which uses glass fibre
Introduction
The PEPCON (or Pacific Engineering Production Company) had a facility based outside Henderson in Nevada, USA. The facility was a production site for Ammonium perchlorate, which was a chemical present in rocket fuel, and was one of the biggest plants in America. On the 4th of May in 1988 this facility caught fire, leading to several explosions and resulting in the deaths of two people and the injuries of three hundred and seventy-two. This report will examine why this disaster occurred and what could be done in the future to prevent such a incident from happening again.
The PEPCON Incident
Just prior to lunch, a crew were repairing a wind-damaged steel and fiberglass building when suddenly a stray spark from their welder set the structure alit. In order to calm the flames, the men went to collect water hoses stored in the plant. Despite their combined efforts, the fire continued to spread towards the 55-gallon drums stored nearby. This was a great concern as over four-thousand tons of ammonium perchlorate was in storage that day. [1 ]
Just 15 months prior, The Challenger Explosion occurred resulting in NASA pausing the space shuttle program to investigate what went wrong. The U.S government however, kept a contract with the PEPCON plant at the amounts before The Challenger Explosion. Therefore, the containers were full of the unused fuels.
In addition, due to strong winds, the ammonium perchlorate had spread throughout the chemical site over the years; leading to the fire being able to spread easily and engulf the whole site. According to PEPCON employees, explosion occurred 10-20 minutes from the time of the spark to the first drum explosion. [2].The explosion erupted, causing 6 building to be evacuated with one worker, Roy Westerfield who was handicapped staying behind to call 911. [1]
The Chief of the Clark County Fire Department noticed the smoke immediately and ordered his units to go to the location as soon as possible. Due to the immense scale of the explosion, the fire department could only get within a 1-mile radius of the site due to the large safety risk posed to the emergency fire brigade. The cloud of smoke was one thousand feet in the sky and could be seen from up to a hundred miles away. The fire department proceeded to help once the flames had consumed most of the fuel. [] From the 77 PEPCON employees at work that day, 75 survived; two died. One was confined to a wheelchair from not escaping on time. [ 2]
Related image
Figure 1 :https://www.bimmania.com/pepcon-disaster_087ebb295.html
Causes of Explosion
Regarding the causes to the disaster, the fire department of Nevada did not issue a formal report describing how the destruction of the plant occurred, but they did issue a press release a month after the incident describing what caused the fire to start, eventually leading to the destruction of the facility.
A windstorm that occurred during the night of May the 3rd 1988, damaged a fibreglass structure inside the plant. The fibreglass structure required a lot of maintenance work and so the next day, a maintenance crew attempted to repair the structure using welding.
Image result for storage tanks chemical plant
Fig 2 plasticon-canada-supplies-chemical-storage-tanks-to-ashbridges-bay-wastewater-treatment-plant
Since the winds were still quite strong, some of the sparks from the welding torches were blown away from where the repair crew were working, and one of these sparks ignited on ammonium perchlorate residue. This residue was situated all over the plant and was quite close to the fibreglass structure. This meant that the fire grew quite rapidly meaning the maintenance workers were not able to put the fire out. They attempted to dull the flames using hoses but the wind was carrying the fire around far too quickly for them to manage. The fire was making its way over to 55 gallons worth of ammonium perchlorate and the workers on the plant knew this would end in an explosion so they evacuated the plant as quickly as they could.
There were over 4 thousand tonnes of ammonium perchlorate stored in the plant so this lead to an abundance of huge explosions. There was a total of seven explosions which took place, the largest being equivalent in size to the detonation of one thousand tonnes pf TNT.
Repercussions
After the incident Nevada’s Chemical Accident Prevention Programme was set up following the passing of the Chemical Catastrophe Prevention Act by Nevada legislature three years after the incident in 1991.
Although PEPCON only had 1 million dollars in insurance after a long courtroom battle with many insurance companies they managed to secure $71 million in insurance most of which was shared between the victims’ families.
PEPCON lawyers initially tried to hold the Southwest Gas Company responsible claiming that the ammonium perchlorate explosions were caused by a natural gas fire. In support of their claim one of PEPCONs lawyers falsely stated that- Nothing ignites ammonium perchlorate. It does not burn. It is not flammable. Before the PEPCON explosion ammonium perchlorate was never perceived as dangerous however many chemists disputed the lawyers statement branding the chemical compound as ‘unstable and highly flammable.’
Before one year had passed since the incident PEPCON changed their name to Western Electrochemical Company (WECCO) .Instead of rebuilding on the original site they moved the built a new plant in a more remote area near Cedar City, Utah. To avoid another explosion the natural gas at the new plant is stored and transported mainly above ground which is different to the previous PEPCON plant. Despite their precautions another explosion took place at the new plant on 30th July 1997 where one person was killed and four people were injured. The one fatality of the second explosion was Danny Balduck who was working as a supervisor in the PEPCON plant when the first disaster occurred.
Conclusion
To conclude, it is evident from the information in his report that The PEPCON Disaster was indeed
References
[ ] Alan Bellows, 7th February 2007, “The PEPCON Disaster”
[] National Aeronautics and Space Administration(NASA), November 2012,System Failure Case Study, Vol. 6 Issue 9, “From Rockets To Ruins” ,p.p2
Available from: https://sma.nasa.gov/docs/default-source/safety- messages/safetymessage-2012-11-05-pepconexplosion.pdf?sfvrsn=ceae1ef8_6
The Pepcon Disaster
Allan Bellows
Written on 07-02-07
Pepcon Disaster
https://en.wikipedia.org/wiki/PEPCON_disaster#Background