The most recent industrial disaster to rock the US occurred on April 17, 2013 in West, Texas. The West Fertilizer plant located in the area was suddenly a crater as a massive explosion took out the plant along with most of the surrounding houses. Fifteen people were killed in the explosion with fire as a contributing factor, and hundreds were injured.
Investigations are still being conducted, but speculations on the primary role of ammonium nitrate stored on plant premises in the explosion have taken good hold. After all, the 1995 Oklahoma City bombing the leveled a whole building and killed 168 people was accomplished with that self-same inorganic compound.
According to Houston law firm Williams Kherker, ammonium nitrate is primarily used as a fertilizer, and in its raw form it is a white crystal. When stored properly, ammonium nitrate is stable, and it takes quite a bit of doing to make the conditions just right for it to combust in an explosive manner such as that exhibited at West Fertilizer.
First, you need a significant amount of the compound all stored in a confined space. Then you have to introduce a source of activation energy, such as a fire. Then once the compound is activated, there needs to be a source of mechanical force, such as a heavy blow, to set off an explosion. Investigators state that such a scenario may have just played out in West Fertilizer.
There is evidence that a fire had broken out in the plant prior to the explosion. It is entirely possible that 28 to 34 tons of ammonium nitrate stored in one of the warehouses was exposed to just enough heat from the fire to be activated, at which point it is speculated that a beam or piece of heavy equipment had fallen onto the ammonium nitrate, providing the final requirement for an explosion.
If ammonium nitrate is found to have been the source of the explosion, it could mean a lot of trouble for West Fertilizer. Ammonium nitrate is a regulated substance, and storage of any significant amount is supposed to be reported to the regulating bodies, which West Fertilizer failed to do. Moreover, the manner of its storage suggest negligence, so the company could be facing criminal as well as civil charges once the final reports are in.