DEFENCE has lost track of almost half a kilogram of plastic explosive.
Despite an investigation, the department has failed to account for the dangerous material, although it has ruled out theft.
Documents released under Freedom of Information show that two 230gram cartridges of PE4 explosive could not be accounted for following a research project on blast damage in June 2012 at RAAF base Williamtown.
The high explosive can be moulded and is widely used by militaries, in commercial blasting and by terrorists.
In this case, a defence researcher proposed detonating 60 cartridges but used only 40. Only 18 of those could be found.
Defence concluded that as the trial was conducted under tight security, it was unlikely the cartridges were stolen.
Because the trial was fully documented, it was also unlikely the explosives were inadvertently let off.
The report said the likely cause was in the defence supply chain. AAP