The first production of guncotton took place in the Marsh Works in 1847. Due to a lack of experience with production methods, an explosion took place soon after work started, with several fatalities. On Sunday 2 April 1916, an explosion occurred at one of the Swale factories in Uplees after sparks from a chimney ignited the works containing around 150 tonnes of high explosives. The incident killed over 100 people, which led to decline of the explosives industry in the town. Later accounts suggested that had the incident not happened on a Sunday, there would have been many more casualties.