There is a village called Hendre outside Mold, North Wales, you can see the top half of the underground building from the road where they tested germ warfare there in the cold war. The rumour is its still contaminated.
You mean these Valley Tunnels at Mold?
The last paragraph of the second page mention the site's original purpose: the storage of vesicant.
Vesicant is another name for various War Gases such as Distilled Mustard, Lewisite, Mustard Gas, Nitrogen Mustard, Phosgene etc.
This is probably where the story of germ warfare testing originated; many people confuse chemical warfare with germ warfare.
Germ warfare experiments were carried out in an underground site in the UK during the Cold War, but not at Mold. Instead, the BW experiments, which involved the dissemination of live bacteria, were conducted at the formerly secret WW2 underground British Museum Repository at Westwood Quarry, Wiltshire.
In the mid sixties, it was proposed to convert the underground tunnels at Mold for use as a Top Secret NATO Civil Agency Headquarters codename WELLBRIGHT, but apparently this proposal never came to fruition.
LAC




