The Health and Safety Authority (HSA) misinterpreted the asbestos legislation that has halted progress on the demolition of the Ballymun tower flats, according to a legal opinion prepared by a senior council.

The HSA has blocked demolition unless asbestos in ceiling materials is first removed, something which Ballymun Regeneration Ltd (BRL) believes will cost the taxpayer up to €120 million.

The current situation is described as a "stalemate" by builders whose projects are blocked as a result of the stand-off between BRL and the HSA. "The whole programme is being delayed," said Mr Donal O'Mahony, a director of Andorey Developments Ltd, a company holding a contract to build student accommodation on Ballymun Road where Pierce Tower now stands.

"It is really not a health reason, it is a political delay," he believes. "We are one of the developers being delayed. The current situation is stalemate. This is going on for the last six months and nothing is happening," he claimed.

The HSA halted demolition of the towers, a central part of the €2.5 billion scheme to regenerate the Ballymun area, after asbestos was detected in artex ceiling coatings in the buildings to be demolished.

The HSA has argued that the European Communities (Protection of Workers) (Exposure to Asbestos) Regulations 1989, later amended in 1993 and 2000, prohibit demolition unless the artex coatings are first removed.

The BRL has countered that asbestos levels are very low and technologies exist to demolish the buildings while preventing the release of airborne asbestos fibres.

Asbestos fibres are a known category one human carcinogen. If breathed in they can become embedded in lung tissue, causing diseases decades afterwards.

It is understood that BRL holds two estimates setting the cost of removing the asbestos prior to demolition at €100 million and €120 million, a cost that would ultimately be borne by the taxpayer.

BRL commissioned senior counsel Mr Mark de Blacam to prepare an opinion on the HSA's interpretation of the regulations, a copy of which has been seen by The Irish Times. In it, Mr de Blacam outlines the debate and exchanges that have taken place so far before concluding that the HSA has misinterpreted the regulations.

Article 15 of the regulations requires that asbestos be removed prior to demolition "insofar as is reasonably practicable", he pointed out. The HSA had called for removal of the artex "before any assessment is made of the risk", Mr de Blacam stated.

"In my view, this is a misinterpretation of the article and indeed of the regulations taken as a whole."

Article 9 forbids an employer from exposing a worker to asbestos without an assessment of the risks, he said, but the HSA wanted the removal prior to this assessment of risk. "In my opinion, limiting the obligation to assess risk in this way is plainly wrong," he stated.

"Equally, I think the HSA is wrong in rejecting cost as a consideration relevant to determining what is reasonably practicable," he stated.

"What is practicable in any given case refers to what is possible or feasible.

"If as appears to be the case in the present instance, the cost of removal is demonstrably uneconomic and furthermore, it can be shown that there is an equally safe, or indeed safer, method of disposing of the asbestos, then it seems to me that the alternative course is not only consistent with the regulations but is indeed mandated by them," he concluded.

The HSA has repeated its current believe, however, that "all asbestos containing materials at the project must, so far as is reasonably practicable, be removed prior to the demolition of the towers".

This, the HSA said, was in keeping with BRL's "legal requirement under Irish law, with industry best practice internationally and is the requisite standard throughout the European Union".

The HSA was charged with enforcement of health and safety standards, a spokeswoman stated.

"The authority must maintain a consistent approach in relation to the removal of asbestos containing materials before demolition regardless of the site location or the parties involved. The setting aside of the clear legal requirement together with European best practice is simply not an option for the authority."

The HSA would continue to make itself available "to advise and assist BRL", she said, adding: "The authority believes that all parties are committed to achieving a satisfactory outcome and we will play our part to facilitate that outcome."