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PEPCON disaster

PEPCON disaster

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The PEPCON disaster was an industrial disaster that occurred in Henderson, Nevada
Henderson, Nevada
-Demographics:According to the 2000 census, there were 175,381 people, 66,331 households, and 47,095 families residing in the city. The population density was 2,200.8 people per square mile . There were 71,149 housing units at an average density of 892.8 per square mile...

 on May 4, 1988 at the Pacific Engineering Production Company of Nevada (PEPCON) plant. The chemical fire
A conflagration or a blaze is an uncontrolled burning that threatens human life, health, or property. A conflagration can be accidentally begun, naturally caused , or intentionally created . Arson can be accomplished for the purpose of sabotage or diversion, and also can be the consequence of...

 and subsequent explosion
An explosion is a rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases. An explosion creates a shock wave. If the shock wave is a supersonic detonation, then the source of the blast is called a "high explosive"...

s claimed two lives, injured 372 people, and caused an estimated US$100 million of damage. A large portion of the Las Vegas metropolitan area
Las Vegas metropolitan area
The Las Vegas Valley is the heart of the Las Vegas-Paradise, NV MSA also known as the Las Vegas–Paradise–Henderson MSA which includes all of Clark County, Nevada, and is a metropolitan area in the southern part of the U.S. state of Nevada. The Valley is defined by the Las Vegas Valley landform, a ...

 10 miles (16.1 km) away was affected, and several agencies activated disaster plans.


The PEPCON plant, located in Henderson, Nevada
Henderson, Nevada
-Demographics:According to the 2000 census, there were 175,381 people, 66,331 households, and 47,095 families residing in the city. The population density was 2,200.8 people per square mile . There were 71,149 housing units at an average density of 892.8 per square mile...

 just outside of Las Vegas
Las Vegas, Nevada
Las Vegas is the most populous city in the U.S. state of Nevada and is also the county seat of Clark County, Nevada. Las Vegas is an internationally renowned major resort city for gambling, shopping, and fine dining. The city bills itself as The Entertainment Capital of the World, and is famous...

, was one of only two American producers of ammonium perchlorate
Ammonium perchlorate
Ammonium perchlorate is an inorganic compound with the formula NH4ClO4. It is the salt of perchloric acid and ammonia. It is a powerful oxidizer, which is why its main use is in solid propellants...

, an oxidizer
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....

 used in solid fuel rocket boosters, including the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...

 and military weapons. The other producer, Kerr-McGee
The Kerr-McGee Corporation, founded in 1929, was an energy company involved in the exploration and production of oil and gas. On June 23, 2006, Houston-based Anadarko Petroleum Corporation agreed to acquire Kerr-McGee in an all-cash transaction totaling $16.5 billion plus the assumption of $2.6...

, was located less than 2.4 kilometers (1.5 mi) away from the PEPCON facility, within the area that suffered some blast damage. In addition to ammonium perchlorate, the facility also had a 16 inches (406.4 mm) high-pressure natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...

 transmission line running underneath the plant.

With the space shuttle program frozen as a result of the 1986 Challenger disaster, there was no government instruction dictating where to ship the product, and no mandated storage procedure or proper storage facilities existed for such large quantities of the product. PEPCON stored almost all manufactured ammonium perchlorate
Ammonium perchlorate
Ammonium perchlorate is an inorganic compound with the formula NH4ClO4. It is the salt of perchloric acid and ammonia. It is a powerful oxidizer, which is why its main use is in solid propellants...

 on-site. After all of the regular aluminum storage bins had been filled, HDPE plastic drums were used for additional storage and placed on campus parking lots. The HDPE plastic acted as a fuel and the ammonium perchlorate as an oxidizer. An estimated 4000 tons of the finished product were stored at the facility at the time of the disaster.

In addition to the PEPCON and Kerr-McGee facilities, there was also a large marshmallow factory, Kidd & Co., about 500 feet (152.4 m) away, and a gravel quarry in operation nearby. The closest residential buildings were about 1 3/4 miles (3 km) away.

Fire and explosions

According to a report by the United States Fire Administration
United States Fire Administration
The United States Fire Administration is a division of the Federal Emergency Management Agency which in turn is managed by the Department of Homeland Security located in unincorporated Frederick County, Maryland, near Emmitsburg.-History:...

, the fire originated around a drying process structure at the plant between 11:30 and 11:40 a.m. that day. A windstorm had damaged a fiberglass structure and employees were using a welding torch to repair the steel frame, causing a fire that spread rapidly in the fiberglass material, accelerated by nearby ammonium perchlorate residue. The flames spread to 55-gallon plastic drums containing the product that were stored next to the building as employees tried in vain to put the fire out with hoses.

The first of a series of explosions occurred in the 55-gallon drums about 10–20 minutes after ignition, and employees had begun fleeing on foot or in cars. About 75 escaped successfully, but two were killed in subsequent larger explosions: Roy Westerfield, PEPCON's Controller who stayed behind to call the Clark County
Clark County, Nevada
-Demographics:As of the census of 2000, there were 1,375,765 people, 512,253 households, and 339,693 families residing within the MSA. The racial makeup of the MSA was 71.6% White , 9.1% Black, 5.7% Asian, 0.8% American Indian and 12.8% of other or mixed race. 22.0% were Hispanic of any race...

 Fire Department; and Bruce Halker, who used a wheelchair and was thus unable to leave. Employees at Kidd & Co., the nearby marshmallow factory, heard the explosion and also evacuated.

The fire continued to spread in the stacks of drums creating a large fireball and leading to the first of four explosions in the drum storage area. The fire then made its way into the storage area for the filled aluminum shipping containers, resulting in two small explosions there, and a massive explosion about four minutes after the first. Little fuel remained after that, causing the flame to diminish rapidly, except for a fireball that was supplied by the high-pressure natural gas line underneath the plant, which had been ruptured by one of the explosions. That gas line was shut off at about 1:00 p.m. by the gas company at a valve about a mile away.

There were a total of seven explosions during the accident. The two largest produced waves measuring 3.0 and 3.5 on the Richter scale
Richter magnitude scale
The expression Richter magnitude scale refers to a number of ways to assign a single number to quantify the energy contained in an earthquake....

. Nearly 4,500 tons (9 million lb) of the product exploded, creating a crater 15 feet (4.6 m) deep and 200 feet (61 m) long in the storage area.

Fire department response

The Fire Chief of the City of Henderson, who was leaving the main fire station
Fire station
A fire station is a structure or other area set aside for storage of firefighting apparatus , personal protective equipment, fire hose, fire extinguishers, and other fire extinguishing equipment...

 about 1.5 miles (2.4 km) north of the PEPCON facility, spotted the huge smoke column and immediately ordered his units to the scene. As he approached the plant, he could see a massive white and orange fireball about 100 ft (30 m) in diameter and dozens of people fleeing the scene.

At about 11:54, as he approached the site, the first of the two major explosions sent a shock wave that shattered the windows of his car and showered him and his passenger with glass. The driver of a heavily damaged vehicle coming away from the plant then advised the chief about the danger of subsequent larger explosions, which prompted the chief to turn around and head back toward his station. The other units also stopped heading toward the site after the explosion.

The second major explosion nearly destroyed the chief's car; after he and his passenger were cut by flying glass, he was able to drive the damaged vehicle to a hospital. The windshields of a responding Henderson Fire Department
Henderson Fire Department
The Henderson Fire Department is the agency that provides fire protection and emergency medical services for the city of Henderson, Nevada, the second largest city in Nevada...

 vehicle were blown in, injuring the driver and firefighters with shattered glass.

Several nearby fire departments responded to the accident. Clark County units staged 1.5 miles (2.4 km) from the scene and assisted injured firefighters. The explosions and the raging fire were beyond their firefighting capabilities and they made no attempt to approach or fight the fire in recognition of the danger it posed.

Evacuation and overhaul of the scene

The Las Vegas Metropolitan Police Department
Las Vegas Metropolitan Police Department
The Las Vegas Metropolitan Police Department is a joint city-county police force for the City of Las Vegas and Clark County, Nevada. It is run by the Sheriff of Clark County, elected every four years. The current Sheriff of Clark County is Douglas C...

, Nevada Highway Patrol
Nevada Highway Patrol
Nevada Highway Patrol is a division of the Nevada Department of Public Safety that is responsible for law enforcement across the entire state of Nevada...

 and the National Guard evacuated a five-mile (8 km) radius around the plant, concentrating on areas downwind of the explosion. Roads in the area were clogged in both directions due to residents trying to leave and curious spectators headed toward the scene, creating a traffic jam that took over two hours to clear.

More than an hour after the first explosions, authorities concluded that the airborne products could be a respiratory irritant. However, it was not considered highly toxic. Nor was the danger of further explosions estimated as high. Authorities had considered expanding the evacuation zone to 10 miles (16.1 km), but the idea was dropped due to the new information, although a few cases of respiratory irritation were reported in a small community about 30 miles (48.3 km) downwind.

Crews in protective clothing headed to the scene to clean up, a slow process due to leaking tanks of anhydrous ammonia and residue from acids and other products. Several firefighters had to undergo treatment for respiratory irritation. Overhaul continued until dusk and resumed the following day. Authorities found the remains of one plant employee, but no trace of the other victim was ever found.

Emergency medical services treated and transported about 100 patients to five hospitals in the region, with the remaining 200 to 300 heading into hospitals on their own volition. Many of the injured had been struck by flying glass when windows were shattered. Fifteen firefighters were injured.

About four hours after the incident, hospitals were advised by the fire department that their disaster plans could be deactivated.

Damage assessment and aftermath

The explosions leveled the PEPCON plant and Kidd & Co marshmallow manufacturing facility. Damage within a 1.5 mile (2.4 km) radius was severe, including destroyed cars, damage to buildings and downed power lines. Damage to windows and moderate structure damage was recorded within three miles (5 km) of the incident.

The damage reached a radius of up to 10 miles (16 km), including shattered windows, doors blown off their hinges, cracked windows and injuries from flying glass and debris. At McCarran International Airport
McCarran International Airport
McCarran International Airport is the principal commercial airport serving Las Vegas and Clark County, Nevada, United States. The airport is located five miles south of the central business district of Las Vegas, in the unincorporated area of Paradise in Clark County. It covers an area of and...

, seven miles (11 km) away in Las Vegas, windows were cracked and doors were pushed open. The shock wave buffeted a Boeing 737
Boeing 737
The Boeing 737 is a short- to medium-range, twin-engine narrow-body jet airliner. Originally developed as a shorter, lower-cost twin-engine airliner derived from Boeing's 707 and 727, the 737 has developed into a family of nine passenger models with a capacity of 85 to 215 passengers...

 on final approach.

An investigation estimated that the larger explosion was equivalent to about 1,000 tons of TNT
TNT equivalent
TNT equivalent is a method of quantifying the energy released in explosions. The ton of TNT is a unit of energy equal to 4.184 gigajoules, which is approximately the amount of energy released in the detonation of one ton of TNT...


Because PEPCON had only $1 million in insurance, a courtroom battle involving dozens of insurance companies and over 50 law firms resulted in a $71 million settlement that was divided among the victims and their families.

After the incident, the company changed its name to Western Electrochemical Co. (WECCO). It built a new ammonium perchlorate plant in an isolated area about 14 miles (22.5 km) outside of Cedar City, Utah
Cedar City, Utah
As of the census of 2000, there were 20,527 people, 6,486 households, and 4,682 families residing in the city. The population density was 1,021.8 people per square mile . There were 7,109 housing units at an average density of 353.9 per square mile...

 with a substantial no-build buffer around it. On July 30, 1997, an explosion at that plant killed one and injured four.

Today the site is a commercial development near the Green Valley residential community. Kidd & Co rebuilt their plant on their original location.


The fire and explosions were caught on videotape by television engineer Dennis Todd, who was on Black Mountain performing maintenance on a television tower. The video footage can be seen frequently on disaster/survival-related television programs, including the following:
  • The Spike TV
    Spike TV
    Spike is an American cable television channel. It launched on March 7, 1983 as The Nashville Network , a joint venture of WSM, Inc...

     series Caught on Tape
  • The History Channel
    The History Channel
    History, formerly known as The History Channel, is an American-based international satellite and cable TV channel that broadcasts a variety of reality shows and documentary programs including those of fictional and non-fictional historical content, together with speculation about the future.-...

     series Shockwave
    Shockwave (TV series)
    Shockwave is an American documentary television series that premiered on November 30, 2007, on History. The program compiles video footage and eyewitness accounts to the headline making events and attempts to educate the viewer as to what really happened in a particular event.The series is a...

    and Modern Marvels
    Modern Marvels
    Modern Marvels is a documentary television series that premiered on January 1, 1995 on History. The program focuses on how technologies affect and are used in today's society....

    : Engineering Disasters
  • The series World's Most Amazing Videos
    World's Most Amazing Videos
    World's Most Amazing Videos is a reality television series, similar to Real TV and Maximum Exposure. Like these shows, it showcases accidents, disasters, police chases and other extraordinary events that are caught on video camera. Although it is similar in content to Maximum Exposure, it takes a...

  • The Discovery Channel
    Discovery Channel
    Discovery Channel is an American satellite and cable specialty channel , founded by John Hendricks and distributed by Discovery Communications. It is a publicly traded company run by CEO David Zaslav...

     series Blueprint for Disaster
    Blueprint for Disaster
    Blueprint for Disaster is a Canadian documentary television series that premiered in 2004 on Discovery Channel Canada. Produced by Temple Street Productions, the program investigates why and how various disasters have happened. Toronto-based Voice Artist Adrian Bell provided the narration for the...

  • The Discovery Channel series Destroyed in Seconds
    Destroyed In Seconds
    Destroyed in Seconds is a half-hour American television series that airs on Discovery Channel. Hosted by Ron Pitts, it features video segments of various things being destroyed fairly quickly such as planes crashing, explosions, sinkholes, boats crashing, fires, race car incidents, floods, etc....

  • The Discovery Channel documentary film Explosions Gone Wrong
  • The NBC
    The National Broadcasting Company is an American commercial broadcasting television network and former radio network headquartered in the GE Building in New York City's Rockefeller Center with additional major offices near Los Angeles and in Chicago...

    series Smash Cuts

External links