Just a few thoughts from an old retired fertilizer chemist about ammonium nitrate ... 1) Yes, a powerful source of oxygen which means you cannot put out a fire involving AN by cutting off the air supply- drown it! 2) Great cheap explosive when mixed with the right fuel e.g. ANFO and suitably detonated 3) Fertilizer grade (used to be called NITRAM) has inert powder (fine limestone,etc.) added to desensitize it to detonation. In some agricultural situations it is preferred over Urea because it does not lose nitrogen if exposed on the soil surface- near enough to same nitrogen content. 4)Sneaky trick... AN melts at 150 deg cent and can self-detonate over 220 degrees WITHOUT extra fuel - melting can negate desensitizing treatment. Chemical breakdown releases orange coloured nitrogen peroxide gas which is very toxic and acidic - bad news! 5) It is normally sold as "prills" which are little hollow balls about 2mm dia, as urea is also. Some years ago there was a big scare in Mackay when a semi overturned with a load of urea in one tonne bags and the local SES flew into action to protect the area from explosion.... guess one little white ball looks much like another! Yes, I know AN has a bad history with overturned semis!
