For those from out-of-state, the "Trib" is the Waco, Texas, USA, newspaper. The agricultural plant in nearby West, Texas, caught fire and suffered an ammonium nitrate fertilizer explosion, some 5 years ago. Recovery from that devastation is now complete. And devastation it was.
---------------------------------------------------------
The 5 year anniversary of the West fertilizer plant
explosion recently passed, with
excellent coverage on TV and in the newspaper regarding recovery since. That recovery is now said to be
complete, and is a testimony to the
people of West, and to all who helped
them.
Many things in life are a sort of “double-edged sword” that
can either help you or hurt you.
Ammonium nitrate is one of those things.
It makes a wonderful fertilizer as a source of fixed nitrogen. It is also a mass-detonable explosive in its
pure form, which is type 100-0-0
fertilizer, something well-known from a
long history of such explosions.
When combined with other fertilizer compounds as something
other than 100-0-0 fertilizer, the
explosive risk goes away. But there is
still an enhanced fire danger, as the
ammonium nitrate decomposes when exposed to fire, releasing oxygen into the fire. That makes the fire very intense.
Now, neat 100-0-0
ammonium nitrate fertilizer is hard to detonate, requiring either the same sort of detonator
as dynamite (just larger), or
confinement when decomposing in a fire.
Without confinement, decomposing
the material in a deliberate fire is actually the best way to dispose of mass
quantities.
The confinement comes from anything heavy resting on top of
the fertilizer (including large amounts of the fertilizer itself, as at Texas City), or containing the fertilizer within some
physical structure as it decomposes from the heat of a fire. The fertilizer itself doesn’t burn, it decomposes. It also melts and runs as a
liquid down into any holes or spaces,
even floor drains.
In a building fire such as happened at the West fertilizer
plant, the confinement is generated by
either (1) the burning building collapses down upon the decomposing
fertilizer, or (2) the melted fertilizer
flows down a floor drain into a pipe.
Either will start the tremendous explosion.
At the West fertilizer plant, it was the building collapse that prompted
the explosion. This event actually
happened after the majority of the stored fertilizer had already decomposed in
the building fire. Had it happened
sooner, much more of (perhaps all) the
town of West would have been obliterated,
and the death toll would have been much,
much higher.
The way to positively prevent ammonium nitrate explosions is
to positively prevent the building fire from collapsing the building in the
first place. Wooden structures, feed,
and grain, plus other building
interior furnishings, are all
flammable: fuel for the fire.
In a new facility, you
simply eliminate all those materials from where ammonium nitrate is processed
and stored. But because the fertilizer
is stored in paper bags, there is still
fuel next to the fertilizer that enhances the fire.
So, you fire-sprinkle
the building according to the specific standards for fertilizer storage (and
these already exist, courtesy of the
National Fire Protection Association).
There is no other way to be certain.
In an existing facility,
there are likely to be wooden floors,
wooden building structure, wooden
storage racks or pallets, and perhaps
even wooden handling and process equipment.
These are all flammable, fuel for
the fire. That makes the fire-sprinkling
of the building even more crucial, plus
it is prudent to seriously over-design the sprinkler system.
Most of these facilities now lie within the city limits of
small towns all over Texas. Many of them
were outside the city limits when originally built, putting them under county (or state)
jurisdiction. If there is no
authorization for a county to impose the fire code standards upon these
facilities, then it is the Legislature’s
job to authorize them to do so, or else
to make it a statewide mandate.
And, believe me, they should do so! There have been many of these explosions over
the past century. There is no excuse to
let money trump public safety. Official
both in public service and in private organizations should be judged by how
they prioritize public safety versus profit.
There is also the problem of urban sprawl. As already mentioned, towns grow toward and engulf these
facilities. Without thinking about the
threat, residences, businesses,
and schools get built right next to facilities handling what amounts to
a high explosive, if mishandled.
What that really means is that local officials need to
understand the true nature of the threat from ammonium nitrate. They need to zone around these facilities as
their locations are annexed into the city,
to restrict development to a safe distance. This has not been happening, but ignorance should not be an excuse!
As for anhydrous ammonia,
it poses much less of an explosion hazard, but something of a toxic gas release
hazard, even in a plant fire. However,
there are standards for these,
too. If applied, the risks are reduced quite effectively. Again,
this starts as a county or state requirement for rural
construction, and those same
requirements should be applied by the cities as they engulf these facilities, as well as proper zoning.
Citizens, you render
your judgements at the polls!
