Thank you. I'm still not positive that the blast is equivalent to the amount of material stored. As substances have different properties. I know nukes are measured in equivalents of TNT. And I'm not certain that this ammonium nitrate would measure in the same way. If I recall it has to do with seismic waves and the the overdressed created, similar to what Jobes mentioned.
A kiloton is a unit of energy equal to 4.184 terajoules (4.184×1012 J). The amount of energy released by detonating 1000 metric tons of TNT.
Ammonium nitrate is the major component of ANFO; it's likely it became contaminated with fuel oil which enabled it to explode.
I'm not sure what the equivalent energy released by ANFO is.
Actually you are right, I'll remove the flair.