The explosion of a ship, loaded with black powder, in Leiden in 1807

In 1807 a ship containing 37,000 pounds of black powder exploded in the centre of Leiden. The effects were devastating, resulting in a large number of casualties and an area of 5.5 ha (5.5×104 m2) completely destroyed. The effects of the explosion were calculated, based on an equivalent amount of 9000 kg of TNT, making use of formulas and knowledge derived from detonation tests with conventional explosives. Within a radius of 168 m all houses are collapsed completely or non-repairable. Smaller damage occurred up to 485 m from the explosion point and in the whole city of Leiden glass windows ruptured. The calculated damage areas correspond well with the actual damage after the explosion.