'''Hanrahan v Merck Sharp and Dohme (Ireland) Ltd''' [1988] ILRM 629, (5 July 1988) is a leading case on Irish tort law and Irish constitutional law. In particular, it considers whether difficulties of proof of causation require the shifting of the onus of proof.

Facts

The plaintiffs managed a dairy farm in County Tipperary, Ireland. The defendants, Merck, Sharp and Dohme, on the invitation of the Industrial Development Authority,[1] had established pharmaceutical plant nearby. Its activity involved the storage, use and disposal of large quantities of toxic substances and dangerous chemical residues. The plaintiffs claimed that the factory had emitted toxic and dangerous gases, dusts, liquids and other substances, such that they suffered ill-health and inconvenience, that his dairy herd did not thrive, that many cattle were born with abnormalities, and that there was a much higher mortality rate among them than would be usual for a farm and herd of his size. They sought damages on the basis of the private nuisance, negligence and the rule in Rylands v Fletcher (1868) LR 3 HL 330, [1868] UKHL 1 (17 July 1868).

At trial before Keane J in the High Court, the matter was dealt with as a claim in nuisance. Unchallenged medical evidence adduced on behalf of the plaintiff was to the effect that, on the balance of probabilities, the plaintiff’s ill-health was caused by toxic emissions from the factory, for that was the only local source of toxic substances. Nevertheless, Keane J found, as a matter of probability, that the human and animal ill-health on the plaintiffs' farm had not been caused by emissions from the defendants’ factory.

Judgment

The Supreme Court allowed the appeal.

Henchy J (Finlay CJ and Hederman J concurring) held that it was sufficient for the claim in nusicane that the plaintiffs establish that they had not enjoyed the comfortable and healthy use of their land to the degree that would be expected by an ordinary person whose requirements are objectively reasonable in all the particular circumstances. He further held that any difficulties facing the plaintiffs in proving that the injuries and losses which they claimed to have suffered were caused by the emissions from the defendants' factory, did not require the shifting of the onus of proof to the defendants:

"The ordinary rule is that a person who alleges a particular tort must, in order to succeed, prove (save where there are admissions) all the necessary ingredients of that tort and it is not for the defendant to disprove anything. Such exceptions as have been allowed to that general rule seem to be confined to cases where a particular element of the tort lies or is deemed to lie, pre-eminently within the defendants' knowledge, in which case the onus of proof as to that matter passes to the defendant. Thus, in the tort of negligence, where damage has been caused to the plaintiff in circumstances in which such damage would not usually be caused without negligence on the part of the defendant, the rule of res ipsa loquitur will allow the act relied on to be evidence of negligence in the absence of proof by the defendant that it occurred without want of due care on his part. The rationale behind the shifting of the onus of proof to the defendant in such cases would appear to lie in the fact that it would be palpably unfair to require a plaintiff to prove something which is beyond his reach and which is peculiarly within the range of the defendant's capacity of proof.

… There are of course difficulties facing the plaintiffs in regard to proof of those matters, particularly as to the question of causation, but mere difficulty of proof does not call for a shifting of the onus of proof."

Henchy J went on to hold that the application of the traditional onus of proof did not infringe Article 40.3 of the Constitution, which protects the personal rights of the citizen. He held that the tort of nuisance may be said to be an implementation of the State’s duty to protect the plaintiffs’ constitutional rights, but he rejected their argument the tort was basically ineffective to protect those rights:

"So far as I am aware, the constitutional provisions relied on have never been used in the courts to shape the form of any existing tort or to change the normal onus of proof. The implementation of those constitutional rights is primarily a matter for the State and the courts are entitled to intervene only when there has been a failure to implement or, where the implementation relied on is plainly inadequate, to effectuate the constitutional guarantee in question. In many torts — for example, negligence, defamation, trespass to person or property — a plaintiff may give evidence of what he claims to be a breach of a constitutional right, but he may fail in the action because of what is usually a matter of onus of proof or because of some other legal or technical defence. A person may of course in the absence of a common law or statutory cause of action, sue directly for breach of a constitutional right (see Meskell v CIE [1973] IR 121); but when he founds his action on an existing tort he is normally confined to the limitations of that tort. It might be different if it could be shown that the tort in question is basically ineffective to protect his constitutional right. But that is not alleged here. What is said is that he may not succeed in having his constitutional rights vindicated if he is required to carry the normal onus of proof. However, the same may be said about many other causes of action. Lack of knowledge as to the true nature of the defendants' conduct or course of conduct may cause the plaintiff difficulty, but it does not change the onus of proof."

Nevertheless, Henchy J held that the second plaintiff had discharged the onus of proof upon him. His medical evidence was to the effect that, on the balance of probabilities, his ill-health was caused by toxic emissions from the factory. Because there was no other opinion to the contrary, and no reason to reject it, that evidence should have been accepted. Likewise, Henchy J held that the animal ill-health had been caused by emissions from the defendants’ factory.

The Supreme Court remitted the matter to the High Court for an assessment of damages; but the case settled; it is believed that the defendant paid damages and costs in the region of Ir£2 million.[2]

Significance

Hanrahan is a leading case on the proof of causation in tort. It emphasises that difficulties of proof of causation do not reverse the onus of proof at common law. However, where a particular element of tort lies, or is deemed to lie, pre-eminently within a defendant’s knowledge, the onus of proof as to that matter passes to the defendant (see Jordan v Minister for Children and Youth Affair [2015] 4 IR 252, [2015] IESC 33 (24 April 2015) [117]-[118] (MacMenamin J); see also Brennan v Windle [2003] 3 IR 494, [2003] 2 ILRM 520, [2003] 3 IR 494, [2003] IESC 48 (31 July 2003)).

The judgment has been criticised by Judge MacMahon and Professor Binchy[3] as departing from the [[Res_ipsa_loquitur#Ireland|res ipsa loquitur]] rule. However, in Rothwell v Motor Insurers Bureau of Ireland [2003] 1 IR 268, [2003] 1 ILRM 521, [2003] IESC 16 (24 February 2003) Hardiman J held that Henchy J’s judgment in Hanarhan is

"authoritative unless and until specifically considered in a case where its reversal is sought. In any event, it appears accurately to state circumstances in which, and the basis on which, the onus of proof may shift in civil litigation. … that is an issue separate from whether the circumstances are those of res ipsa loquitur."

Furthermore, Hanrahan reaffirms that the Constitution does not require such a reversal of the onus of proef where there are difficulties of proof of causation. This is a consequence of the doctrine of [[Separation_of_powers#Ireland|separation of powers]] (see MC v Clinical Director of the Central Mental Hospital [2020] IESC 28 (04 June 2020) [131] (Baker J)). The existing torts are the method by which the State performs its Constitutional obligation to vindicate the personal rights of the citizen; and it is only if those causes of action do not adequately protect the constitutional rights of the citizen that a separate claim for breach of constitutional rights can be invoked (see Clarke v O’Gorman [2014] IESC 72 (30 July 2014) [33] (O’Donnell J); see also Grant v Roche Products [2008] 4 IR 679, [2008] IESC 35 (07 May 2008)). Hence, if the common law is basically ineffective to protect a plaintiff’s constitutional rights, the courts may rely on the Constitution to fashion a remedy (see Nash v Director of Public Prosecutions (No 2) [2016] IESC 60 (24 October 2016) [2.7] (Clarke CJ); Simpson v Governor of Mountjoy Prison [2019] IESC 81 (14 November 2019) [124]-[125] (McMenamin J)).

The leading case on damages for breach of constitutional rights is probably Meskell v CIE [1973] IR 121 , to which Henchy J referred in Hanrahan. However, by requiring that that the common law be "basically ineffective" to protect constitutional rights before Meskell can be relied upon, the "decision in Hanrahan is generally regarded as having ‘tamed’ the impact of Meskell".[4] However, "the test set out in Hanrahan invites courts to endorse the existing tort regime rather than infuse it with constitutional values",[5] and it remains to be seen whether the Hanrahan limitation can withstand ongoing pressures to fashion horiztonal constituitonal remedies.[6]

References

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