The focus of the tribunal returned yesterday to a key decision of the Blood Transfusion Service Board in June 1988 to which four hepatitis C infections can be linked.
At a meeting on the 15th of that month, with only half its members present, the board approved the expert advice placed before it on the production of blood products for haemophiliacs for the following year.
What was agreed was that the BTSB should continue to send Irish plasma to the Armour pharmaceutical company in Germany, where it would be processed under conventional heat-treatment conditions and returned as Factor 8 clotting agent for haemophiliacs, along with a by-product which was made into Factor 9 at Pelican House.
It was this Factor 9 which infected an adult and three children, two of whom were siblings and whose mother, using the pseudonym Felicity, gave evidence to the tribunal last May.
The board made its decision despite being told by Armour to sign a letter of indemnity protecting the company from any legal action over infections. Armour had begun to doubt the effectiveness at that stage of conventional heat treatment in eliminating hepatitis C and was moving towards a safer monoclonal technology instead.
Dr Terry Walsh, the board's former chief medical consultant, who attended the crucial meeting in an advisory capacity, was questioned yesterday about his role in the decision. He admitted that the Armour request for indemnity had "caused concern" and agreed that it meant that if there was a problem with infections it would be "on your own (the BTSB's) head".
Dr Walsh said it was his view at the time that the BTSB should have been moving towards monoclonal or solvent detergent technology, both of which were more effective than heat treatment, but he could not recall whether he expressed this view at the meeting.
It was clear from his evidence that the board had been balancing a number of factors, among them the yield which would have been available from a new producer, when a new product would have become available and the cost of such a product.
Indeed, in his letter to the board, Prof Ian Temperley had noted that some balance "would have to be struck between cost and the infection dangers associated with blood products".
In particular, Prof Temperley expressed concern that a monoclonal or high-purity pro duct could be twice the price of the Armour one and said: "The board should understand that, in the present period of financial stringency, the hospitals could not be expected to meet a doubling of the costs of concentrates in 1989."
It seems that the tribunal will only get to the bottom of this when Prof Temperley is called to give evidence.
At the time of the board meeting, he had held two roles, being director of the National Haemophilia Treatment Centre and a member of the board. What is unclear is which role he was meant to have been playing when he gave his advice, and of particular importance is whether he was asked to make his recommendations within certain financial constraints.
While the infections of the four haemophiliacs can be linked to that board decision, their fates were not sealed until later.
The BTSB had ample opportunity to apply a safer viral inactivation method to conventional heat treatment when it came to making Factor 9 from the supernatant returned from Armour. But it neglected to do so.
Among the options open to the board was super-heat treatment, a method used in Britain, which both Dr Walsh and his predecessor as chief medical consultant, Dr Vincent Barry, knew as early as spring 1987 was effective in eliminating hepatitis C.
Dr Walsh said yesterday that he believed the alternative method used, a variation of conventional heat treatment licensed by Travenol to the BTSB, was equally effective. But, as it transpired, he was wrong.
Further shortcomings of the board in administering the Factor 9 product have already been disclosed to the tribunal. Last month, it learnt that the adult patient who was infected received the contaminated product in October 1990, one month after one of the three children had tested positive for hepatitis C.