The rapid expansion of the RAF during the mid/late 1930s necessitated a massive storage requirement for high explosive bombs and other ordinance. Drawing on the experience of the Great War ammunition factories, the authorities set about identifying underground sites around Britain safe from the threat of air attack. Limestone quarries such as Chilmark in Wiltshire and slate mines (Llanberis) were ideal. Unfortunately in the haste of the moment safety arrangements were not a high priority and as a result there were over the ensuing years a number of appalling accidents; the most serious occurred in November 1944 at the huge (45 acre) Fauld Gypsum Quarry, Staffordshire. 4,800 tons of HE bombs detonated at the same time and resulted in the deaths of 68 people directly and more from gassing later. The book goes on to discuss the post-war disposal programme.