Gelignite , also known as blasting gelatin or simply jelly, is an explosive material consisting of collodion-cotton (a type of nitrocellulose or guncotton) dissolved in either nitroglycerine or nitroglycol and mixed with wood pulp and saltpetre (sodium nitrate or potassium nitrate).
It was invented in 1875, by Swedish chemist Alfred Nobel, who also invented dynamite. It is more stable than dynamite, but can still suffer from "sweating". Its composition makes it easily moldable and safe to handle without protection, as long as it is not near anything capable of detonating it.
In the United Kingdom, an explosives certificate, issued by the local Chief Officer of Police, is required for possession of gelignite. Due to its widespread civilian use in quarries and mining, it has historically been often used by irregular or paramilitary groups such as the Irish Republican Army and British loyalists.
The 1970s saw Irish Industrial Explosives Limited producing annually 6,000 tonnes of Frangex, a commercial gelignite intended for use in mines and quarries. It was produced at Ireland's largest explosives factory in Enfield, County Meath. The Gardaí and the Irish Army patrolled the area, preventing the IRA from gaining direct access.
However, indirectly, the Provisional Irish Republican Army (PIRA) acquired amounts of the material. At the time of his arrest 3.5 kilograms (7.7 lb) was found in the possession of Patrick Magee and 300 kilograms (660 lb) discovered in a hijacked road tanker in January 1976.
PIRA volunteer, later informer, Sean O'Callaghan estimated that planting 25 pounds (11 kg) of Frangex would kill everyone within a 60-foot (18 m) radius. The Real IRA (RIRA) also acquired Frangex, and, in December 2000, eighty sticks were discovered on a farm in Kilmacow, County Kilkenny, near Waterford.