SAFETY officers closed the Corwen Pavilion after concerns over asbestos.
Denbighshire County Council, which owns the site, said it took the step after a leak in a heating duct.
They described the move as a precautionary measure while investigations take place.
But tests carried out over the weekend by J B Monitor - asbestos contractors, found that levels of white asbestos were within permitted limits.
Three bulk samples taken from the roof void have all come back negative and air samples that were taken were all below 0.01F/ML.
Safety certificates will now be issued.
The issue of the heating duct leak still remains and will have to be investigated and repaired by Denbighshire’s building maintenance team, which will result in a further closure for a short time.
The pavilion, one of the largest public halls in North Wales, was built in 1911, and was the location of the Urdd Eisteddfod in 1921.
A spokeswoman for Denbighshire County Council said: “The Control of Asbestos Regulations 2006 state that we have a duty to identify where asbestos is in any of our buildings and put robust systems in place to either manage it or remove it.
“Denbighshire has a management process for asbestos in place and we are working through this process in accordance with the regulations to limit the impact of the closure.”
Head of leisure services, Jamie Groves, said: “This is extremely good news.
“Contractors and Denbighshire officers have worked hard over the weekend to establish whether there has been any risk to the public and these positive results are very welcome.
“We will now continue working with the Corwen Pavilion User’s Forum to look at both short term and longer term options for the site.”
All current bookings at the venue have been cancelled, and a strict "no entry" policy enforced at the building, until investigations are finished.
u Asbestosis, which is caused by breathing in asbestos fibres and can lie dormant for up to 40 years, could kill up to 10,000 people a year by 2020.
Asbestosis can cause lung cancer and cancer of the lining of the chest and lungs.
Blue and brown asbestos - the most dangerous kinds - are banned in the UK, but can still be found in some old buildings.
White asbestos was not considered as dangerous until recently.