When heated, ammonium nitrate decomposes non-explosively into nitrous oxide and water vapor; however, it can be induced to decompose explosively by detonation into oxygen, nitrogen, and water vapor. Large stockpiles of the material can be a major fire risk due to their supporting oxidation, and may also detonate, as happened in the Texas City disaster of 1947 which led to major changes in the regulations for storage and handling. There are two major classes of incidents resulting in explosions: Ammonium nitrate decomposes in temperatures above 169 °C. Pure AN is stable and will stop decomposing once the heat source is removed, but when catalysts are present, the reaction can become self-sustaining (known as self-sustaining decomposition, or SSD). This is a well-known hazard with some types of NPK fertilizers and is responsible for the loss of several cargo ships.

Timeline of major incidents

The column AN states the amount of ammonium nitrate consumed in the disaster in metric tonnes.