August 27 2009 marks 70th anniversary since the Treasury approved a £546,000 development of a World War II weapons plant - in 2009 it's a nature reserve

For years the secrecy surrounding the Rhydymwyn Valley Site, near Mold, served only to fuel rumour about what, if anything, could still be hidden in underground tunnels that once housed thousands of mustard gas shells during the height of production in the war years.

And speculation has been rife for the last few decades since it was revealed that the works played a role in the research into the first atomic bomb.

But specialists from Birmingham University, who surveyed the site, released their findings in May 2006 - saying there were no more secrets lying hidden in the underground tunnels as they were empty.

Historic buildings experts are to be asked to conduct a study aimed at safeguarding a former top secret munitions factory in Flintshire.

Rhydymwyn Valley Works, near Mold, reputedly made 40,000 mustard gas shells weekly during World War II, and research which helped develop the first atomic bomb was carried out.

Local historians are concerned about the worsening state of the buildings.

They said the studies, ordered by the UK government, were "wonderful news".

The Rhydymwyn Valley History Society (RVHS) wrote to Delyn MP David Hanson asking for help in preserving the Grade II-listed buildings.

In a letter to the MP, Environment Secretary Caroline Spelman said: "DEFRA is commissioning Purcell Miller Tritton, a historic building consultancy, to undertake a complete condition survey of the buildings on site and create a five year preservation plan.

"This will be developed in conjunction with the conservation bodies for Wales, including Flintshire County Council."

Colin Barber, RVHS chairman, said: "This is wonderful news.

"There's an urgent need to get work started because these buildings wouldn't survive the same level of degradation that they suffered last winter.

"We just need to know now when they're going to get work started."

The RVHS wants the site developed as a visitor attraction.

However, the Environment Secretary ruled out the idea of allowing visitors to tour the tunnels of the underground complex.

Her letter said there was a "potential for toxic gas exposure" and the tunnels offered a risk of trips and falls.

She also rejected the Society's suggestion that parts of the site could be taken over by an outside organisation for development as an attraction.

Mr Barber said: "We don't accept what the minister is saying.

"We firmly believe that this site has great potential as a tourist attraction and we'll be seeking a meeting with Defra to discuss the way forward.

"We want to see it opened up that everyone can have the opportunity of visiting the site and finding out what happened there."