Ammonium nitrate, which Lebanese authorities have said was the cause of the Beirut blast, is an odourless crystalline substance commonly used as a fertiliser that has been the cause of numerous industrial explosions over the decades.
These include notably at a Texas fertiliser plant in 2013 that killed 15 and was ruled deliberate, and another at a chemical plant in Toulouse, France in 2001 that killed 31 people but was accidental.
