The first direct link was made by the tribunal yesterday with one of the witnesses who gave personal testimony last month on hepatitis C infection.
Three haemophiliac children, whose mother gave evidence under the pseudonym Felicity, were identified as having being infected with clotting agents used by the Blood Transfusion Service Board in the late 1980s, long after it had been alerted to safety fears over them.
Two of the children were infected with a batch of heat-treated factor 9 issued in July 1989. The product had been made from Irish plasma by the drug company Armour, which 18 months earlier had expressed concern over the product and agreed to continue with its production only after the BTSB had signed a letter of indemnity.
The third child was also exposed to the product but according to Dr Emer Lawlor, the BTSB's deputy medical director, he was more likely to have been infected by a commercial product made from plasma from the Middle East or Egypt.
In her evidence last month, Felicity described her treatment at the hands of the BTSB as "unforgivable" and was especially disturbed by the fact that she was not informed until late 1995 that the children had been infected. "For five years their livers were untreated, unmanaged," she said.
The mother learnt of the infections only after calling the Haemophilia Treatment Centre at St James's Hospital to report that one the three had become depressed and withdrawn. A nurse replied that it was probably his hepatitis. The tribunal heard yesterday that the children had tested positive for hepatitis C in January 1989, September 1990 and December 1990.
Even more damaging for the BTSB was the disclosure yesterday that the contaminated factor 9 product was also administered to an adult haemophiliac in October 1990. This was a month after one of the two children infected by the BTSB product had tested positive for hepatitis C.
The man, who had a mild haemophilia B condition, also became infected, as did a fifth individual, a child who, like the three siblings, was born after 1985. He also got the virus through the factor 9 batch numbered 9885.
There is little doubt the BTSB should not have been using such a heat-treated product at this late stage. Whatever about in the early 1980s when technologies for combating hepatitis C were underdeveloped, in 1989 conventional heat treatment had been discredited as a method of protection.
Britain had by then been using a superheat-treatment procedure, which the BTSB declined to pursue, for four years. France and Switzerland had been using a solvent detergent method for two years, the same method which the BTSB eventually adopted in 1989.
Why the BTSB used heat-treated factor 9 when it had already started giving patients solvent detergent products was a question left unanswered yesterday.
A possibility is that the board simply did not wish to see old products being thrown away. There was concern at the time over shortages in plasma supply. It was also a period of budgetary restrictions.
The board continued to send Irish plasma to Armour for processing until August 1989, and the drug company returned factor 8 and factor 9, which was subsequently heattreated at Pelican House, right up to February 1990. In the meantime, the BTSB started sending plasma to the Scandinavian firm Octapharma, where the solvent detergent method was used, a method which has yet to be linked with any infections.
At the close of evidence, Judge Alison Lindsay adjourned the tribunal until Monday when the cross-examination of Dr Lawlor by the Irish Haemophilia Society's legal team is due to begin.
The adjournment was granted after an application from counsel for the society, Mr John Trainor SC, for new documents to be submitted to the tribunal in the light of Dr Lawlor's evidence which, he said, seemed to have taken a "different form" from her initial statement.