HAZMAT Explosions: What happens in Vegas, stays in Vegas?

CarolinaFireJournal - David Greene
David Greene
10/14/2011 -
A series of explosions occurred in Henderson, Nevada (a Las Vegas suburb) on May 4, 1988. The explosions virtually destroyed two industrial facilities, cracked windows and buffeted a Boeing 737 on final approach at McCarran International Airport seven miles away, and damage extended for a radius of up to 10 miles away. The explosions were registered on the Richter scale at an observatory in California, left a crater 15 feet deep and 200 feet long, and the resulting fire produced smoke that rose to an altitude of several thousand feet. — visible almost 100 miles away. After reading our case study for this issue (United States Fire Administration Technical Report Series), this author has come to terms with why the first United Nations/North American (UN/NA) Hazard Classification is Explosives. image

In recognition of our recently retired space shuttle, it is appropriate that we take this issue to recognize the hazardous material that allows the space shuttle to defy gravity, leave the ground, and reach an orbit above the earth in eight minutes. The Pacific Engineering Production Company of Nevada (PEPCON) was the site of the aforementioned explosions. PEPCON was one of only two free world producers of ammonium perchlorate, an oxidizer used in solid fuel rocket boosters such as those on the Space Shuttle and military weapons. Its NFPA 704 label has a Blue – 1, Red – 0, Yellow – 4, and White – “OX.” Although ammonium perchlorate does not readily burn, it is a very unhappy chemical that reacts to friction and heat with explosive results. It is made utilizing anhydrous ammonia, hydrochloric acid, nitric acid, and various chlorate compounds. At the time of the explosion at PEPCON, there was a large marshmallow factory within 500 feet of PEPCON’s facility. (I don’t make it up, I just read and write it).

Identifying the hazardous material involved is often very difficult. At fixed facilities, we have a bit of an advantage if we are completing our pre-incident surveys correctly, which should give us an idea of every material the facility possesses. In transportation however, the game is much different. Not long ago, the department for which this author works responded to an overturned tractor-trailer. The trailer was a full-size box type trailer with no visible placards; however, the driver was concerned that the contents may have spilled from its packages inside the container. The driver did not have any shipping papers but stated he had just left the port about 90 minutes prior to the motor vehicle collision. A call to the port office with the container number led them to admit they had no idea what was on the trailer. The driver assisted in locating the receiver — a company in Tennessee — which, when contacted, also could not identify what the material in the trailer was. The trucking company eventually — hours into the incident — located an order form from the receiver and relayed that they thought the material was aluminum powder, a combustible metal which is water reactive. Upon examination of the cargo, it was found that none of the material had breached its individual containers. The trailer was righted without incident.

As a courtesy, the truck driver was transported to a local hotel via an administrative vehicle. During the trip, the truck driver was questioned regarding the lack of shipping papers and he described a disturbing fact. He stated that when dealing with the port, if the foreman in charge of loading the container on the trailer determined that the material was “not hazardous,” they do not issue the driver a set of shipping papers. In this case, the aluminum powder must have been thought to be non-hazardous, but nothing could be further from the truth.

It is worth re-visiting the quote from Paracelsus, a 15th century physician who is often known as the “Father of Modern Toxicology” who said, “All things are poison, and nothing is without poison, only the dose permits something not to be poisonous.”

Water is the best example of this. Water is a basic building block of life and without it we would all die in a matter of days. However, if one were to take a four foot straw and place it inside a 55 gallon drum of water and drink the drum’s contents in five minutes, they would meet the same results, death. A fluid overload such as this would not only cause a pH shift in the body but would overload the circulatory system and cause multi-organ failure. This is the prime example where the dose separates the poisonous from the non-poisonous.

Ammonium perchlorate, what PEPCON produced, is a white powder with an auto-ignition temperature of 464.0 degrees Fahrenheit. Its health and fire hazards are fairly limited but the fact that it is a strong unstable oxidizer, produces toxic gases when burned, and is highly reactive makes it a formidable opponent. Although particle sizes over 15 microns (micrometers) are classified as oxidizers, particle sizes less than 15 microns are classified as explosives due to their aberrant behavior.

Let’s pause a moment and ask ourselves a question. Since our tractor-trailer drivers probably don’t know what the material is, what are the odds they will know the particle micron size? The answer is obvious and demonstrates how far behind the curve we may be when we arrive to a hazardous materials incident in transportation.

PEPCON had received some windstorm damage and a welding torch was being used to affect repairs. Some fiberglass material was ignited inadvertently and spread quickly through some ammonium perchlorate residue in the area. Employees initiated and continued suppression efforts for 10 to 20 minutes until the fire reached some nearby 55-gallon drums containing ammonium perchlorate which subsequently exploded. At this point, employees began evacuating from the facility and alerted the nearby marshmallow factory who also began evacuation. Only two employees remained behind, one who was wheel chair bound and could not self-extricate and the other was notifying the fire department. The first of two major explosions allowed the fire to spread to a storage area filled with aluminum shipping containers which led to a second larger explosion — search “PEPCON Explosion” on YouTube.

The Fire Chief of the City of Henderson was arriving just as the first explosion occurred. The shock wave shattered the windows of his car and showered the chief and his passenger with glass. The second explosion is the one described at the beginning of this article — that tried to take down an airliner seven miles away.

After the second explosion, very little fuel remained, but a high pressure natural gas line was breached under the facility which immediately began venting heavy fire. Incoming engines were staged approximately one mile away when the second explosion occurred. It virtually destroyed the chief’s car and damaged several apparatus as windshields were blown in and personnel were injured by shattered glass.

Clark County units were requested as mutual aid, since the Henderson Fire Department was incapacitated, in what would be part of a three alarm response. These units staged 1.5 miles away but their initial size up found that both the PEPCON facility and neighboring marshmallow plant had been completely destroyed. Given the magnitude of fire in the PEPCON facility, the fact that there was no water supply due to the only hydrants being in the area of fire involvement, and recognizing the futility, no attempt was made to approach or to fight the fire. A five mile evacuation radius was implemented and the military, U.S. Department of Energy, state and local EPA agencies initiated air monitoring of surrounding areas. After the natural gas line was secured and the fires subsided, crews were faced with leaking anhydrous ammonia tanks which required extensive work to contain.

As one could imagine, the time it took to gather and analyze information regarding this incident at its onset, resulted in incorrect information being broadcast and caused widespread public confusion. Within an hour, Clark County Fire Department’s Public Information Officer arrived and established a reliable source of information for the media outlets. This emphasizes the need for establishing working lines of communication with sources of media in your jurisdiction — especially if you’re in an urban area where the press might beat your first-in engine to the call.

When it was all over, the PEPCON incident claimed two lives (the two who remained behind during the PEPCON evacuation), injured approximately 372 people, including 15 firefighters and one infant that was seriously cut by glass from a broken window, more than two miles from the scene. Approximately 300 patients were distributed over an area of 50 to 75 square miles which negated the adage, “What happens in Vegas stays in Vegas.”

This is a lesson that Henderson, Nevada would be painfully reminded of in May of 1991 during a very large chlorine release. (See Carolina Fire Journal – Fall 2008 - Hazardous Material Incidents: Would you like to phone a friend?). Final PEPCON damage estimates were over $100 million.

Imagine arriving at a hazardous materials incident only to be met with a massive explosion that cripples your department’s ability to mitigate the hazards. Although we may not be offered exact information on what the material is as soon as we arrive, we have to strive — and sometimes struggle — to at least classify the material. If we know it is a UN/NA Hazard Class 1 (Explosive), we know to stage far away from the container. We can figure out later whether it is a Class 1/Division 1 (1.1) which presents a mass explosive hazard or a Class 1/Division 6 (1.6) which is extremely insensitive articles without a mass explosive hazard. Likewise, if we know it is a UN/NA Hazard Class 8, then we know it is a corrosive. We can figure out later whether it is an acid or a base.

Determining the hazard class should be our first step. Does it really matter to us if the material is Hydrochloric Acid or Muriatic Acid? It shouldn’t as they are virtually the same thing. We just need to figure out the chemical classification. From there, we can begin to process the information, enter the scene — where appropriate —  take samples to determine exactly what the chemical is, and then determine the best course of action.

We have reviewed two scenarios. In the transportation scenario (involving the tractor trailer), we had no idea what we were dealing with until long after arriving at the incident. As soon as we arrived at the fixed facility scenario — in Henderson, Nevada — the chemical, by littering the chief’s car full of holes, let us know not only that it was an explosive (UN/NA Hazard Classification # 1), but that we were also close enough to it. The information we can obtain in our pre-incident surveys and the information we must extract from the multiple players involved in transportation will help us find a happy middle ground between these two extremes.

Be safe and do good.

David Greene has over 20 years experience in the fire service and is currently the Assistant Chief with Colleton County (SC) Fire-Rescue. He is currently working on his PhD through Oklahoma State University. He is a certified Executive Fire Officer through the National Fire Academy, holds the Chief Fire Officer Designation and is an adjunct instructor for the South Carolina Fire Academy. He is also a Nationally Registered Paramedic, is certified through Fire Officer IV, a Resident Fire Marshal and a certified Fire and Explosion Investigator through the National Association of Fire Investigators. He can be reached at [email protected].
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