On 6 February 1939, an action taken by Michéal and Bríd O'Cionnfaola against Daniel McCarthy and the Wellcome Foundation Ltd began before the President of the High Court, Mr Justice Conor Maguire. The O'Cionnfaola's claimed damages in respect of the death of their daughter, Siobhán, and in respect of loss and personal injuries sustained by their three sons, due to illness incurred following immunization treatment at Ring College. The plaintiffs alleged that the TAF preparation used during the inoculations at Ring ‘was negligently prepared, manufactured, tested, or stored by the Wellcome Foundation’ and issued by them to Dr Michael O'Farrell, ‘containing tubercle bacilli’. The claim against Daniel McCarthy did not infer that he performed his duties in a perfunctory manner, but that he ‘warranted the quality and fitness of the preparation used’. Opening for the plaintiffs, E. J. Kelly stated that the case was of ‘vast and critical importance’. Kelly continued:

In Britain, contemporary medical practitioners regarded the charge levelled against the Wellcome Foundation as somewhat audacious, bordering on the impudent. One contributor to the British Medical Journal referred to the whole case as ‘extraordinary’, and given the reputation of the manufacturers, the charge that a preparation of TAF was contaminated when it left the laboratory, ‘seems incredible’. In the House of Commons, William Leach, Labour MP for Bradford, raised concern regarding the safety of Wellcome's prophylactic, asking if it was ‘the same as that freely used in this country’. While health minister Walter Elliott allayed parliamentarian's concerns, he instructed his department to open up a line of correspondence between Whitehall and the Custom House in Dublin. Dr J. R. Hutchinson, Deputy Senior Medical Officer at the Ministry of Health, requested a transcript of evidence presented at the High Court proceedings from his Irish counterpart Robert McDonnell, stating ’Questions in the House of Commons have already arisen out of this incident and it seems likely that we may have others.