Nasa / Space

Geek Trivia: Fuel for disaster

What famous disaster led directly to the PEPCON explosion years after the fact?

On May 4, 1988, the U.S. National Earthquake Information Center (NEIC) in Colorado detected a seismic event of magnitude 3.5 on the Richter scale, situated in or around Henderson, Nevada. At first blush, it appeared to be an earthquake barely strong enough to be felt by locals, but still notable to the NEIC's sensitive instruments. Turns out, however, that the NEIC didn't detect an earthquake, but a man-made event.

On the outskirts of Henderson, onlookers got an all too up-close-and-personal glimpse at what it's like to detonate eight million pounds of rocket fuel, almost all at once.

The Pacific Engineering Production Company of Nevada (PEPCON) was a primary government contractor for the manufacture of ammonium perchlorate, which is an active oxidizer for solid rocket fuel. (It was essential to every U.S. Titan IV missile.) Note the past tense of that statement. At the end of the day on May 4, 1988, where the PEPCON facility used to sit was instead a crater 15 feet deep, 200 feet wide, filled with a smoldering fireball of shrapnel and smoke.

A series of explosions roughly equivalent to a small nuclear weapon literally wiped PEPCON off the map. The PEPCON blasts, rated as one of the most powerful non-nuclear detonations in history, injured hundreds and literally changed the landscape of the surrounding area.

Surprisingly, the PEPCON blast only claimed two lives. Both were employees that failed to evacuate the plant when the initial fire started. One was Roy Westerfield, who bravely stayed behind to make the 911 call that alerted nearby firefighters as to the impending blast.

Those same firefighters stopped miles short of the PEPCON facility when the first preliminary detonation occurred, effectively disabling the local fire chief's car (and shattering all its windows) before he ever got to the plant proper. Realizing that the bulk of the fuel had not caught fire yet, and they couldn't contain the fire before a much larger blast occurred, rescue workers turned their attention to evacuation. These actions mitigated the loss of life attributed to the PEPCON disaster. Still, to say only two lives were lost in the PEPCON disaster is somewhat a matter of selective bookkeeping.

The PEPCON blast, you see, was in many ways just the last aftershock of a much more famous tragedy, one that claimed seven additional lives years earlier, but that led directly to the PEPCON explosion.

WHAT FAMOUS DISASTER LED DIRECTLY TO THE PEPCON EXPLOSION YEARS AFTER THE FACT?

Get the answer.

About

Jay Garmon has a vast and terrifying knowledge of all things obscure, obtuse, and irrelevant. One day, he hopes to write science fiction, but for now he'll settle for something stranger -- amusing and abusing IT pros. Read his full profile. You can a...

27 comments
Tin Weasle
Tin Weasle

I remember the PEPCON bast. I was filling up my gas tank at an AM/PM on East Tropicana at the time. My girlfriend (later wife) was working at a company that was further south, with nothing but desert between them and the PEPCON complex. The big winners that day were the window glass companies. Lots of shattered windows in Henderson and south Las Vegas (Paradise area). The video of the blast was amazing, though, ripples radiating from the blast site like ripples in the water of a pond. It is frankly amazing that more damage and loss of life didn't happen.

rsaulpaugh
rsaulpaugh

When I was a kid I saw a B-52 blowup. It was at 4 in the morning and the horizon was filled with angry orange clouds, alive and clawing their way into the sky. But that was before the bombs went off...

alinder
alinder

I went looking for the video lytlej mentions (the one taken by the lineman) and found this: http://video.aol.com/video-detail/pepcon-explosion-may-1988/1249549102 It's an 8-minute story about the PEPCON disaster on the History Channel which includes that clip of video. Watch as a sandy shockwave quickly demolishes a building in the compound as it spreads from ground zero (narrated at 4:30 but shown several times). Amazing.

alinder
alinder

(I tried to delete this duplicate post - the next one is the one I wanted to keep)

boomchuck1
boomchuck1

It appears that we do have a lot of rocket scientists here! We should be able to figure anything out! Good article and fun reading.

Gem in VA
Gem in VA

Generally speaking, fireballs don't smolder. The smoldering stage comes before or after the fireball, n'est-ce pas? :-)

michael.tindall
michael.tindall

Titan missiles are liquid fueled. I believe you are referring to the Minuteman series.

psf
psf

You say "all because of a lost space shuttle two years earlier, and the unforeseen fallout of that horrific tragedy" but it sounds like the company was a disaster waiting to happen. Inadequate insurance, improper storage, etc. I wouldn't blame the government for the company not handling its own product properly.

Parrish S. Knight
Parrish S. Knight

The Wiki entry on the disaster says it's ammonium perchlorate, not aluminum perchlorate. Which one is it? (This isn't necessarily a quibble; I have no idea, myself.)

lytlejeva
lytlejeva

I lived in Henderson when this happened. I was at work at Nellis AFB, about 11 miles away. My house was only 3-4 miles away. Here's what I remember. I was outside my office and saw the initial plume of black smoke, then next felt the rumble like an earthquake. At my house, every garage door on the street was caved in. I had one broken window and my living room wall (cathederal ceiling) had structural damage. Supposedly the oxidizer is not considered 'fuel' within self, it needs something combustible to cause the explosion. Much speculation was made that the underground natural gas lines had been leaking, although this was denied by the gas company. The only video that I know of was taken by a technician on an antenna tower on a nearby mountainside. He usually had his video camera with him to document his work and the presence of mind to film the explosion. The video does show the donut-shaped shockwave which resembles that of a nuclear blast. On a humorous note, my daughter was in second grade at the time. Damage at the school was pretty much limited to fallen ceiling tiles. When she saw on TV the film of the marshmallow plant, and the firefighters wading in waist-deep marshmallow, she was very concerned that there wouldn't be any more marshmallows. We had to reassure that there were other places that made them as well.

jlafitte
jlafitte

The Titan and Titan II series missiles were LIQUID fuel-propelled, NOT solid-fuel. The article writer may be thinking of the Minuteman series of ICBMs, which ARE solid-fuel propelled. You're not helping yourselves by not fact-checking these blogs, folks. It makes me wonder what else in this post is wrong.

michael.tindall
michael.tindall

Ignore. Y'all beat me to it, and did a better job of it.

w2ktechman
w2ktechman

no orders coming in, and NASA was not flying missions -- why were they still creating fuel at full capacity? I think you are right -- the company was very poorly managed, and it was their fault.

ESchlangen
ESchlangen

From the shuttle website: "The propellant mixture in each SRB motor consists of ammonium perchlorate (oxidizer, 69.6% by weight), aluminum (fuel, 16%), iron oxide (a catalyst, 0.4%), a polymer (such as PBAN or HTPB, a binder that holds the mixture together, also acting as secondary fuel, 12.04%), and an epoxy curing agent (1.96%). This propellant is commonly referred to as Ammonium Perchlorate Composite Propellant, or simply APCP. This mixture develops a specific impulse of 242 seconds at sea level or 268 seconds in a vacuum. The main fuel, aluminum is used because it has a reasonable specific energy density of about 31.0MJ/kg, but having a high volumetric energy density, as well as being difficult to accidentally ignite. The propellant is an 11-point star-shaped perforation in the forward motor segment and a double-truncated-cone perforation in each of the aft segments and aft closure. This configuration provides high thrust at ignition and then reduces the thrust by approximately a third 50 seconds after lift-off to avoid overstressing the vehicle during maximum dynamic pressure"

tkeller
tkeller

I was in my apartment off-base when I felt the rumble and the windows rattled. I thought I was experiencing my first earthquake. I was clueless until later that afternoon.

jlafitte
jlafitte

The perchlorate oxidizer had plenty of fuel around it - the containers it was stored in, the buildings of the PEPCON complex, everything (and everyone) remaining in the area after ignition began. If a natural gas pipeline ran under or very near the PEPCON property, the extreme heat of all that perchlorate decomposing at once might have caused a breach in the pipeline. Not to mention that perchlorate decomposing would have contributed considerable heat and energy to the detonation which occurred.

Jay Garmon
Jay Garmon

I should have been more specific, as I was referring to the then-contemporary (1988) version of the Titan, the Titan IV, which had solid rocket booster components. http://en.wikipedia.org/wiki/Titan_IV You're right that the Titans I and II had no SRBs, and the Titan III had optional SRBs. The main engine was LOX for every titan, but the heavy lift later models depended heavily on SRBs. Sorry for the imprecision.

Roadrace1
Roadrace1

They were obligated by contract to continue production, the government was paying them to do so. Basically they were storing government property because the government hadn't made arrangements for or issued instructions regarding shipping to/storage at another location. Jay doesn't go into detail regarding any communications between PEPCON and NASA regarding the developing situation at PEPCON but anyone who has dealt with the government can imagine how this happened. To blame the company for NASA's mismanagement is out of line.

blieffring
blieffring

Once the APCP ignited, the blue polyethylene barrels became fuel, like fuel oil in Ammonium nitrate/fuel oil.

tradergeorge
tradergeorge

So does this mean that "Aluminum Perchlorate" is a misnomer? The article refers to Aluminum Perchlorate on the first page and Ammonium Perchlorate on the second page....

seanferd
seanferd

and do not need fuel or flame to explode. Benzoyl Peroxide is a good example. There are many unstable compounds that need only a small energetic nudge to cause runaway decomposition, which results in expanding gases and the heat of the binding energy which was used to form the compounds in the first place. The addition of fuel to an already exothermic decomp of unstable oxidizers... well, we've seen the results.

fred.wagner
fred.wagner

I don't know about the Titan I's, but the Titan II's used UDMH (Unsymmetrical Dimethyl Hydrazine) as fuel and Red Fuming Nitric Acide as Oxidizer. Those were chosen because they were storable at 'room' temperature, and were hypergolic (ignite on contact). The missiles were kept ready to launch at 60F, always fueled,60 seconds from key turn to out of the silo. The Kerosene/LOX fuel combination of fuels is also hypergolic, but LOX has to be kept REALLY cold - thus the insulated external tank on the Shuttle. The shuttle also uses Hydrazine fuel for its maneuvering engines, which is why the first people near a shuttle after landing are the guys in protective suits to make sure there's not fuel leakage. Hydrazine is EXTREMELY toxic, and Red Fuming Nitric Acid burns worse than clorox ever did! (breath any of it and acid dissolves your lungs!) I spent 50 months as a Titan II Launch crew commander at Tucson, AZ Fred Wagner ex MCCC crew R-152

jlafitte
jlafitte

You're right (sort of). The SRBs light off first, and it's only two seconds into flight that the liquid fuel (Aerozine 50 fuel and nitrogen tetroxide oxidizer since the Titan II, though, not LOX) engine starts. But you're right that those strap-on SRBs did make Titan IVb a replacement system for orbiting those major defense support loads that the Shuttle was designed to lift. Without them, the heavy-lift mission would have been a joke for a Titan booster. Darn, I should know better than that, I live about twenty minutes from where they made the things (Lockheed Martin Space Systems).

alinder
alinder

...if the History Channel's story of it is correct (see my post The Video! below), they say that after the shuttle blew up and the program was on hold, "PEPCON kept making it [AP] anyway, stockpiling tons of the dangerous chemical hoping to sell it the future." So was the stockpiling was speculative, not contractual... or did History Channel get the facts wrong (entirely possible)?

jlafitte
jlafitte

How often did you guys have to de-fuel those things, anyway? I seem to recall that the 1980 Titan II silo detonation in Arkansas happened during a routine de-fueling/re-fueling operation. Someone dropped a wrench on the rocket or something...

jlafitte
jlafitte

Beginning with Titan II - as I said in an earlier post - the fuel was Aerozine-50 (a 50-50 mixture of hydrazine and UDMH developed for use in the Titan 2 missile) and the oxidizer was nitrogen tetroxide. http://www.astronautix.com/props/n2oine50.htm is an authoritative source. So is John C. Clark's "Ignition," Rutgers University Press, 1972 (amazon listing at http://tinyurl.com/6dauav) Dr. Clark ran the Navy's rocket fuel development program in New Jersey throughout the early Cold War.

HavaCigar
HavaCigar

unsymmetrical-dimethyl-hydrazine would ring a bell? Mixed with LOX for the Titans. It was 9th grade research paper...

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