This was revealed at a recent hearing of the Legislative Assembly's standing committee on education, training and youth affairs inquiry into the future use of the Fitters Workshop.

The ACT government allocated $3.8 million in its 2011-12 budget for a capital works project to relocate Megalo Print Studio to the Kingston arts precinct, including the Fitters Workshop, but this was delayed because of controversy from the music community, having discovered an unusual acoustic quality in the workshop.

The inquiry, chaired by MLA Amanda Bresnan, was tasked with investigating the best use of the workshop, taking into account the acoustic qualities, heritage value, its location, cost and community demand of the building.

An executive from the government's Economic Development Directorate, Chris Reynolds, said 18 months was reasonable for construction work and the planned annexe for Megalo Print workshop.

But he said there was a range of contamination and remediation exercises that needed to be undertaken which would add to that time frame.

''We are still waiting for the outcomes of this standing committee prior to finalising the draft master plan that the LDA has prepared,'' he told the committee, which is expected to deliver its findings at least a month late.

''We are aware from going through historical records that, I think in the vicinity to the east, there were some old storage tanks that have been disused for some time. The records are a bit sketchy about exactly what was in them but, again, being precautionary, we would assume that some testing would need to be done,'' he said.

It was unknown whether the tanks were used for water or fuel such as diesel which may have contaminated the soil near the old bus depot.

Cindy Cantamessa, of the Economic Development Directorate, told the committee, ''There would need to be additional validation testing around the fill material to see whether they have leaked, but they will need to be extracted and then they will have to do more testing to ensure that the soil is okay. So it is a process to verify the soil.''

Mr Reynolds told the inquiry there were always three layers of process. ''An expert consultant, an independent auditor and then the EPA. What we have typically found is that with those three levels the process works very well but it is not a quick process.''

The Canberra Times understands independent experts are in high demand which may delay the process even further.

''The actual physical works would probably be the quickest,'' Mr Reynolds said. ''The time will be taken in the checking, the sign-offs and the approval of what needs to be done, if it is contaminated.'' Ms Cantamessa said six months was a ''ballpark figure''.