The file consists of correspondence between the Engineer to the Humber Conservancy Board (Arthur Ernest Butterfield until 1946, then Ralph John Hindmarsh), the Superintendent of the Upper Humber, and the Lincolnshire Constabulary. The subject matter is a proposed annual visit to the Explosives Store on Read’s Island in the Humber and also discussion on an increasing trend of robberies at explosive stores elsewhere in the country, particularly in the West Riding of Yorkshire and the North Midlands. Within the file there is also correspondence with explosives companies (including cartridge suppliers).

Another topic covered by the correspondence is discussion between the Humber Conservancy and companies wishing to disperse the wrecks 'Iona' and 'Dinah' using explosives.