Chemical Weapons Plant – Valley Works Rhydymwyn



Valley Works – Rhydymwyn


During the 1930’s and the threat of war with Germany looming the government decided a facility capable of producing and storing chemical weapons was required. In 1939 after surveying many sites in the area work was started at Rhydymwyn, building one of the UK’s most top and best-kept secrets. Several different weapons were made here but Mustard Gas was the main product, and this was made in two forms, Pyro, which was the same as the gas used in the First World War, and Runcol, which was developed later. Pyro had a major disadvantage compared to Runcol as it could not be used at altitude due to its high freezing point so it could not be dropped form the air. Runcol became the main product to be produced and this soon became a problem with the tunnelling of an under ground storage facility not complete which resulted in above ground sites chosen for temporary storage. During 1942 Pyro production was now at a stand still but remained ready to start up if chemical weapons were ever used against us. One of the pyro buildings (Building 45), which was not in use and remained empty, became the home of an Ultra Secret Project known as Project X and the building became an Atomic Research Facility. By 1943 there was large-scale uranium separation and research into Isotope separation. This was some of the earliest work to be carried out on the development of the Atomic Bomb and continued until the Americans joined the war, research was then transferred out of Valley and became the Manhattan Project. The full truth about the site will never be known and following environmental checks a lot of the site has now been demolished to remove contamination, toxic burial pits have been capped and the site has been returned to nature.

As the site was wound down it was still being maintained and Chemical Weapon production capability remained well into the 50’s. Modifications where carried out on site this included reinforcing of the tunnel entrances and the fitting of blast doors. Valley remained in a shroud of mystery as it became a Forward Supply Depot in the Cold War and possibly a Command and Control Centre. There were stockpiles of food, medicine, bedding and who knows what else? Just about everything needed to survive a nuclear war. There were secret plans for the tunnels, which were Projects Wellbright, Mallard and Trojan. Project Wellbright was the plan to locate the NATO Oil Executive Board (NOEB) at Valley, Project Mallard the storing of the Bank of England gold and Project Trojan the utilisation of the tunnels as a safe haven in the case of nuclear attack. The locals didn’t know much about the place and was know locally as ICI or the rubber factory to help hide it’s real purpose.

By this time it was the UK’s premier Nuclear Bunker, a bit ironic really being where the Atom bombs development was started



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