Site Records

Site Name: Little Heath (FFD1) Forward Filling Depot

Station Road
Barnham Heath, Suffolk
OS Grid Ref: TL853779

Sub Brit site visit 6th November 2003

Barnham Heath is a largish area between Barnham and Thetford part of which is still used for military training (Barnham Camp) and part of which is in private hands. There were two areas of the heath related to chemical weapons (mustard gas). The north site later became the 94 Maintenance Unit Nuclear Bomb Store and is now the Gorse Industrial Estate. The south site (south of the Barnham - Elvenden road), most of which was sold to the Elvenden Estate, was the site of the Little Heath Forward Filling Depot (FFD) and the three 500 ton bulk storage pots. This area comprises 1.7 acres and is crossed by a public right of way. The depot remained in MOD hands until April 1997 when it was handed over to the Defence Land Agent prior to sale.

The chemical name for mustard gas is dichlorodiethyl sulphide. At normal temperature it is a liquid, rather like diesel oil in appearance with a smell similar to garlic. It was used as a war gas because it is a 'vesicant' which means that contact with the liquid or vapor will cause blisters on the skin similar to third degree burns and if inhaled will cause serious damage to the lungs which will almost inevitable cause death. Its value in conflict was due to the fact that it does not decompose and will remain active in the ground or on materials it has contaminated for many days, in fact months or even years. This makes it completely different from the effects of chlorine or phosgene which, as gasses, are readily dissipated in the atmosphere.

It is comparatively easy to manufacture given a supply of raw materials which are mostly readily available chemicals and there are really only two effective ways of decontaminating; one is by the application of bleaching powder and the other by burning.

There are two types of mustard gas, Runcol (HT) which is produced by the method used by the Germans in WW1 by reacting thiodiglycol (known as 'Syrup' during the war) with hydrochloric acid and Pyro (HS) which is produced by combining ethylene with sulphur dichloride. Runcol was more expensive to manufacture and was not suitable for tropical storage.

Chemical warfare was developed in Germany in 1915 but the allies were quick to respond with their own production and in the later years of WW1 mustard was used by both sides. Although chemical weapons were banned by the Geneva Protocols of the 1920's this did not stop their use by the Japanese in 1931 and the Italians in 1935 and even Churchill supported their deployment. With the coming of WW2 it was decided that the manufacture of chemical weapons should once again be undertaken to act as a deterrent as Germany would almost certainly be producing them.

Mustard gas was produced by ICI from 1938 at their Randle plant on Wigg Island near Runcorn in Cheshire and initially weapons were filled or 'charged' at Randle. It soon became clear that a safe storage facility was required for these weapons and in 1939 work started building the Valley Works at Rhydymwyn in North Wales.

In 1941 it was proposed that five forward filling depots (FFD) should be constructed and they were ready for use by 1944. The five depots were:

The layout of the five FFD's is similar, the major buildings being storage sheds for empty cases, a bonding building, a charging building(s) where the cases were filled; these buildings were linked together by covered ways . There were also underground storage tanks knows as 'pots' where the chemical agent was stored; at Little Heath there were three of them, each holding 500 tons of chemical agent. At Little Heath there were two charging buildings and a railway loading dock inside the bonding shed with a short spur from the Thetford - Bury St. Edmunds Railway Line.

No munitions were filled at the site after 1945. Immediately after the war, due to the danger of storing filled munitions over long periods, it was decided to decant agent out of the 65 lb LC (light case) bombs and the spray tanks into storage tanks and dispose of the munitions by incineration followed by dumping.

Agent was decanted into the three large pots capable of holding 500 tons of mustard each. Decanting and burning of US munitions (1000/115 lb bombs and M47-A2 chemical bombs) left behind also took place. Some barrels (presumably used in the decanting process) were burnt locally and others sent to Risley FFD to be burnt. This activity continued until about 1949 when the storage pot pipework was dismantled.

Diesel powered burner at Randle

Stocks of new munitions continued to be stored at the site in case new supplies were needed and in 1946 unspecified quantities of mustard were taken to the Valley Works at Rhydymwyn in North Wales for storage in support of a continuing military requirement.

Further information and pictures about this site continues here

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