An Explosive ROF was a UK Government-owned Royal Ordnance Factory (ROF), which specialised in manufacturing explosives during and after World War II. Note: In World War I, the name used in the UK for Government-owned explosives factories was National Explosives Factory; and the Cordite factory at Gretna was known as HM Factory, Gretna. Pyrotechnics, such as fuzes and screening smokes, tended to be made at the Filling Factories and filled directly into munitions.