Supreme Court

Mary Hanrahan, John Hanrahan and Selina Hanrahan
										(Plaintiffs)

v.

Merck Sharp & Dohme (Ireland) Limited
										(Defendants)

No. 316 of 1985
[5th of July, 1988]

Status: Reported at [1988] ILRM 629

Henchy J. (Finlay CJ and Hederman JJ concurring)
 
1.	The general nature of the case
The plaintiff Mrs. Mary Hanrahan is the registered owner of a farm of about 264 acres at Ballycurkeen, Carrick-on-Suir, Co. Tipperary. It was a thriving dairy farm and was run by Mrs. Mary Hanrahan with the aid of her husband until his death in 1969, and then with the aid of her daughter Dolly until the latter left the farm on her marriage in 1978. The management of the farm then devolved on her son the plaintiff John Hanrahan who lives there with his wife the plaintiff Mrs. Selina Hanrahan and their two children, Charles (17) and Ambrose (15).
The farm is situated in a quiet pastoral valley which up to 1976 was virtually free from industrial activity. That rural serenity was interrupted in March 1976 when the defendants, who are a branch of a large American-based industrial group engaged in the manufacture of pharmaceuticals, opened a factory for the manufacture or processing of pharmaceutical products in the nearby townland of Ballydine, about a mile from the plaintiffs’ farm. The factory employs about 250 people.
The factory is primarily engaged in the compounding or processing, at one stage or another, of particular pharmaceutical products. Its activity therefore necessarily involves the storage and use of large quantities of toxic substances and compounds and the keeping in the factory area, and the ultimate disposal therein as waste, of toxic and dangerous chemical residues. Clearly a high degree of care is necessary to avoid the risk of causing personal injury or material damage by the emission from the factory of toxic gases, vapours or other dangerous substances.
The complaint of the plaintiffs has been that from about 1978 until 1983 operations in the factory were conducted in such a way that the emission of toxic and dangerous gases, dusts, liquids or other substances was such that they each suffered ill-health and inconvenience, that they were subjected to offensive smells, that lack of thrift, abnormalities and deaths resulted in the farm animals, that damage was caused to herbage and plant life, and that there was corrosion of metal surfaces on the farm.
The plaintiffs commenced proceedings against the defendants in the High Court in 1982 seeking injunctions restraining the operation of the factory in a manner resulting in the damaging emissions complained of and claiming damages for the personal injuries and material damage alleged. The case came on for hearing in February 1985 and the hearing lasted 47 days. Reserved judgment was given by the trial judge in August 1985 dismissing the plaintiffs’ claim, primarily on the ground that the personal injuries, loss and damage complained of had not been shown to have resulted from any act or default on the part of the defendants.
The plaintiffs now appeal to this Court against that dismiss of their claim.

2.	The legal basis of the claim
The plaintiffs have formulated their claim on the basis of nuisance, trespass, negligence and breach of the rule in Rylands v Fletcher (1868) LR 3 HL 330. By the time the case came to court, the claim for an injunction had disappeared, for the conduct of the defendants’ operations in the factory was no longer charged as warranting the issue of an injunction. What has been in issue in the High Court and in this Court is whether a claim for an award of damages has been made out.
The claim as based on trespass has not been proceeded with, presumably because it could not readily be said that any of the loss or damage complained of was a direct or immediate result of the acts complained of. The loss and damage could more properly be said to be consequential on the conduct complained of.
Neither has the claim in negligence been pursued with any vigour. Where negligence is pleaded, the plaintiff must prove the appropriate degree of want of care. It would not be proper in a case such as this to have the plaintiffs’ case judged by the application of a particular standard of care on the part of the defendants, when the plaintiffs are entitled to make a case which does not require proof of a want of care on the part of the defendants. Hence, the plaintiffs rely on nuisance and Rylands v Fletcher.
To provide a basis for the award of damages for the private nuisance relied on, the plaintiffs have to show that they have been interfered with, over a substantial period of time, in the use and enjoyment of their farm, as a result of the way the defendants conducted their operations in the factory. The plaintiffs do not have to prove want of reasonable care on the part of the defendants. It is sufficient if it is shown as a matter of probability that what they complain of was suffered by them as occupiers of their farm in consequence of the way the defendants ran their factory.
The alternative claim under Rylands v Fletcher derives from the rule formulated in that case by Blackburn J, (1866) LR 1 Ex. 265, at p. 279:-

We think that the true rule of law is that the person who for his own purposes brings on his land and collects and keeps there anything likely to do mischief if it escapes, must keep it in at his peril, and if he does not do so is prima facie answerable for all the damage which is the natural consequence of its escape. He can excuse himself by showing that the escape was owing to the plaintiff’s default; or, perhaps, that the escape was the consequence of vis major or the act of God; but as nothing of the sort exists here, it is unnecessary to inquire what excuse would be sufficient.

The escape in question in Rylands v Fletcher was that of water from an artificial reservoir on the defendant’s land which flooded a mine on the plaintiff’s adjoining lands.
In many cases – of which the present is one – liability may be determined under either Rylands v Fletcher or nuisance. In some cases liability arises in nuisance only, such as where the damage has been caused by noise or by something which cannot be categorised as a thing which is likely to cause mischief if it escapes. Contrariwise, in some cases liability requires to be determined under Rylands v Fletcher, such as where the plaintiff is not an occupier of land, or where the damage complained of was not so repeated or continuous as to be what in ordinary parlance could be described as a nuisance.
In the present case the defendants clearly brought on their land things which were likely to cause mischief if they escaped, i.e. dangerous chemical substances. The plaintiffs claim that there were repeated and prolonged escapes, in one form or another, of those substances, so that the plaintiffs as the occupiers of their farm suffered in their health and in their enjoyment of life, the livestock on the farm were grievously affected, and damage was caused to the land and to certain property on the land. While the case could have been disposed of in the High Court by the application of either the rule in Rylands v Fletcher or the law governing a claim in nuisance, the trial judge seems to have dealt with the claim as essentially one in nuisance. Since in neither the notice of appeal nor in the submissions made to this Court has it been contended that the judge erred in this respect, it is proper that this Court should also treat the plaintiffs’ claim as one in nuisance.

3.	The onus of proof
It is common case that the probative aspect of a claim in nuisance has been correctly expressed by Gannon J in the following passage from his judgment in Halpin and Ors v Tara Mines Ltd High Court 1973, No. 1516P, 16 February 1976.

A party asserting that he has sustained material damage to his property by reason of an alleged nuisance must establish the fact of such damage and that it was caused by the nuisance as alleged. It is no defence to such a claim, if established, that the activities complained of were carried out with the highest standards of care, skill and supervision and equipment or that such activities are of great public importance and cannot conveniently be carried out in any other way. In so far as the nuisance alleged consists of interference with the ordinary comfort and enjoyment of the property of the plaintiff, his evidence must show sensible personal discomfort, including injurious affection of the nerves or senses of such a nature as would materially diminish the comfort and enjoyment of, or cause annoyance to, a reasonable man accustomed to living in the same locality. To my mind the reasonable man connotes a person whose notions and standards of behaviour and responsibility correspond with those generally pertaining among ordinary people in our society at the present time, who seldom allows his emotions to overbear his reason, whose habits are moderate and whose disposition is equable.

It is clear from the authorities on the law of nuisance that what an occupier of land is entitled to as against his neighbour is the comfortable and healthy enjoyment of the land to the degree that would be expected by an ordinary person whose requirements are objectively reasonable in all the particular circumstances. It is difficult to state the law more precisely than that.
In this case the plaintiffs’ main complaints, namely that the emissions from the factory damaged their health and that of the livestock on the farm, are of so pronounced and serious a nature that no question of nicety of reaction arises. Either those complaints were caused by the emissions from the factory or they were not. If on the balance of probabilities they can be said to derive from factory emissions, then the case for nuisance has been made out. Anything short of that degree of proof would not support a finding of nuisance.
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.
That is not the case here. What the plaintiffs have to prove in support of their claim in nuisance is that they suffered some or all of the mischief complained of and that it was caused by emissions from the defendants’ factory. To hold that it is for the defendants to disprove either or both of those matters would be contrary to authority and not be demanded by the requirements of justice. 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. Many claims in tort fail because the plaintiff has not access to full information as to the true nature of the defendant’s conduct. The onus of disproof rests on the defendant only when the act or default complained of is such that it would be fundamentally unjust to require the plaintiff to prove a positive averment when the particular circumstances show that fairness and justice call for disproof by the defendant. The argument put forward in this case for putting a duty of disproof on the defendants would be more sustainable if the plaintiffs had to prove that the emissions complained of were caused by the defendants’ negligence. Such is not the case. In my view, having regard to the replies given by the defendants to interrogatories and notices for particulars and to the full discovery of documents made by them, it is not open to the plaintiffs to complain that for want of knowledge on their part it would be unjust or unfair to require them to bear the ordinary onus of proof.
The plaintiffs have also invoked the Constitution in support of their argument as to the onus of proof. They contend that the tort relied on by them in support of their claim is but a reflection of the duty imposed on the State by Article 40.3 of the Constitution in regard to their personal rights and property rights. The relevant constitutional provisions are:-

1º  The State guarantees in its laws to respect, and as far as practicable, by its laws to
defend and vindicate the personal rights of the citizen.
2°  The State shall, in particular, by its laws protect as best it may from unjust attack and
in the case of injustice done, vindicate the life, person, good name, and property rights
of every citizen.

I agree that the tort of nuisance relied on in this case may be said to be an implementation of the State’s duties under those provisions as to the personal rights and property rights of the plaintiffs as citizens. The particular duty pointed to by the plaintiffs is the duty to vindicate the personal right to bodily integrity and the property right to their land and livestock. They say that vindication of those rights under the constitutional guarantee is not properly effective by leaving them to their rights as plaintiffs in an action for nuisance and that the vindication they are guaranteed requires that once they show that they have been damnified in their person or property as alleged, it should be for the defendants to show that emissions from their factory were not the cause.
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 C.I.E.  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.
It is also to be noted that the guarantee to respect and defend personal rights given in Article 40.3.1º applies only ‘as far as practicable’ and the guarantee to vindicate property rights given in Article 40.3.2° refers only to cases of ‘injustice done’. The guarantees, therefore, are not unqualified or absolute. I find it impossible to hold that Article 40.3.1° means that a plaintiff in an action in nuisance is to be relieved of the onus of proving the necessary ingredients of that tort. Neither, in my view, does Article 40.3.2° warrant such a dispensation, for the guarantee of vindication there given arises only ‘in the case of injustice done’, so it is for the plaintiff to prove that the injustice relied on was actually suffered by him and that it was caused by the defendant.
I would hold that the trial judge correctly rejected the submission of the plaintiffs that an onus of disproving the allegation as to causation should rest on the defendants.

4.	The appellate jurisdiction of this Court
In a case such as this, where the function of the trial judge was to decide whether the plaintiffs had suffered the loss or damage complained of and, if so, whether the defendants’ factory was a causative source of that loss or damage, the jurisdiction of this Court in reviewing the judge’s findings of fact on appeal is necessarily limited. Statements as to the limitation of a court of appeal’s power to interfere with a trial judge’s finding of fact are to be found in a number of cases, but the most recent statement emanating from this Court on the matter is to be found in J.M. and G.M. v An Bord Uchtála [1988] ILRM 203, at p. 205:-

For the purpose of an appeal from a judge of the High Court to this Court, facts may be divided into two categories.
Firstly, there are primary or basic facts. These are determinations of fact depending on the assessment by the judge of the credibility and quality of the witnesses. It is for the determination of those facts that a viva voce hearing takes place. Because those facts depend on the oral evidence given and accepted in the High Court, this Court on appeal will not normally reverse such findings. Even if it deems different findings to be more appropriate, or even if the findings made seem to be incorrect, this Court will not normally interfere with them. That is because it has not had the advantage of seeing and hearing the witnesses as they gave their evidence. It is only when the findings of primary fact cannot in all reason be held to be supported by the evidence that this Court will reject them: see Northern Bank Finance Corp Ltd v Chariton [1979] IR 149.
Secondly, there are secondary or inferred facts. These are facts which do not follow directly from an assessment or evaluation of the credibility of the witnesses or the weight to be attached to their evidence, but derive from inferences drawn from the primary facts. Once the primary facts have been established viva voce, their consequences or implications for the purpose of the matters in issue must be found by a process of deduction from the facts found or admitted, rather than by an assessment of the witnesses or of the weight or the correctness of their evidence. In regard to such secondary facts, the advantage of the High Court judge who saw and heard the witnesses is of such minor importance that this Court will feel free to draw its own inferences if it considers that the inferences drawn by the judge in the High Court were not correct. Such secondary facts include all matters which are evaluative of the primary facts.

It is noteworthy in the present case that most of the primary facts, particularly the facts as to the existence of the matters complained of, are not in dispute. The real controversy, both in the High Court and in this Court, is whether as a matter of probability it can be held that emissions from the factory were a cause of the trouble. That is essentially a matter of inference. If, having found the primary facts, the judge was reasonably entitled to infer from them that the balance of probability did not identify emissions from the factory as causative of the complaints, the plaintiffs are not entitled to succeed in this appeal. On the other hand, if on a fresh appraisal of the primary facts as found or admitted, this Court is of opinion that the likelihood is that factory emissions were causative of the complaints, then this Court is entitled to substitute a conclusion to that effect for the exculpatory conclusion reached by the trial judge.

5.	The nature and scope of the complaints relied on
The complaints relied on as supporting the claim for damages may be broadly classified as follows:-
1. Ill-health suffered by each of the plaintiffs.
2. Ill-health, abnormalities and deaths, occurring in the cattle on the plaintiffs’ farm.
3. Personal inconvenience and discomfort, mainly in reference to smells, suffered by the plaintiffs.
4. Damage to herbage and plant life on the farm.
There was originally a complaint also as to damage by corrosion of metal surfaces on the farm, but this ground of complaint has not been pursued.
There is no doubt, and it seems to have been so found by the judge, that during the relevant time (i.e. 1978 to 1983) each of the plaintiffs suffered ill-health; the health of the dairy herd deteriorated and abnormalities of different kinds and deaths took place among the cattle; discomfort and distress were evident in man and beast, particularly in relation to the effect on the plaintiffs of offensive smells; and there was an observable retardation of and damage to growing things.
The judge’s dismiss of the plaintiffs’ claim in respect of each of those complaints was, as the judgment shows, due to his finding that as a matter of probability they had not a common cause, namely factory emissions. While the plaintiffs’ claim rested primarily, on evidence of what was felt or observed at the time, the defendants’ case was primarily one of rebuttal based on scientific evidence of a reconstructive nature. It is for that reason that counsel for the plaintiffs have urged that there is greater force and credibility to be given to the first-hand evidence of witnesses whose truthfulness was not called into question, as opposed to the largely abstract ex post facto evidence of scientists who had no direct or personal experience of the matters complained of. Consideration must of course be given to such a submission, as well as to the submission that the various complaints should not be viewed in isolation, that they are necessarily interlinked, and that evidence of the source of one complaint may be treated as corroborative or confirmatory of the source of another complaint, such as that the evidence of a witness that he experiences an offensive chemical smell should be coupled with his evidence that at the very same time he noticed cattle in deep distress. Such direct sensory perception, it is urged, may be pointed to as sufficient to prevail over scientific opinions as to the non-toxic cause of the distress in the cattle.

6.	The complaint as to smells
I deal with this complaint first, not because it is the most serious, but because it is the most amenable to clear resolution and because it casts direct light on the other complaints.
The evidence as to offensive smells from the defendants’ factory was extensive and largely uncontroverted. I give the following abbreviated samples from the evidence.
The plaintiff John Hanrahan gave evidence that he began to experience an unpleasant smell in 1979. According to him it was ‘a dreadful smell, a really dreadful smell’. He complained about it to the factory on numerous occasions. On the occasion of one of those complaints Mr. Wyatt, an executive in the factory, said that the waste system had gone wrong. Mr. Hanrahan described the smell as foul and as following him into the house. He said that on one occasion the smell was accompanied by ‘a dreadful burning’ and that his skin was affected.
The plaintiff Mrs. Mary Hanrahan said that she first experienced a bad smell in 1978. It was so bad that some people thought their haybarn was on fire. She described the smell as being like what she describes as the horrible smell that is emitted when a blacksmith puts a hot iron on a horse’s hoof. She said that when she complained to the factory people about the smell they said it would never happen again.
The plaintiff Mrs. Selina Hanrahan described how she experienced unpleasant and distressing smells accompanied by clouds of emissions from the factory and which frequently caused her eyes to stream.
John Callanan, a neighbouring farmer who lives about a mile to the east of the factory, said he first noticed the foul smell in the Spring of 1979. He complained of it to Mr. Wyatt in the factory, who explained the smell by saying that they had gone over to the manufacture of a product called sulpinac. Mr. Callanan said that, despite assurances given, the offensive smell returned in the Autumn of 1979 and became so offensive and pervasive that they used never open the windows of their house. According to him the smells continued to be emitted by the factory until May 1983.
John Tobin, a neighbouring farmer who lives about a mile to the north of the factory, described experiencing unpleasant smells on five or six occasions.
Martin Long, a farmer who lives about 100 yards from the factory, said that he experienced unpleasant smells from the factory from twelve to twenty times in the late 1970s. The smell was so severe that his mother, with whom he lives, complained to the factory.
John Wallace, whose land is about 2½ miles to the north of the factory, said he first noticed the unpleasant smell from the factory in July 1983. ‘It was strong, objectionable, very objectionable. You would not stay too long where it would be’. He again experienced it in 1984, but then it was a stronger, burning smell and he felt somewhat overcome by it.
Thomas Rockett, whose farm lies 1½ miles north-east of the factory and beside the plaintiffs’ farm, said that in 1981 he noticed a range of different smells from the factory, some of which would ‘burn the eyes out of you’.
The foregoing is but a short selection from the evidence given as to the intensity and frequency of the objectionable smells from the factory. Not alone were the plaintiffs’ complaints as to smells amply corroborated but the defendants admitted that they had received complaints as to smells on over 200 occasions. It is not surprising that the judge’s conclusion as to the existence of the smells was as follows:

There is undoubtedly evidence that on a number of occasions the processes carried on in the defendants’ factory were responsible for offensive odours which were legitimately and reasonably objected to by the plaintiffs and many others living in the area of the factory.

However, he went on to find that ‘it does not appear that they [the odours] were ever on such a scale or intensity as to justify the award of damages’. This conclusion seems to me to be incorrect, not so much as an inference drawn from the facts as a misinterpretation of the relevant law.
As I have pointed out earlier in this judgment, by reference to the cited passage from the judgment of Gannon J in Halpin and Ors v Tara Mines Ltd, where the conduct relied on as constituting a nuisance is said to be an interference with the plaintiffs’ comfort in the enjoyment of his property, the test is whether the interference is beyond what an objectively reasonable person should have to put up with in the circumstances of the case. The plaintiff is not entitled to insist that his personal nicety of taste or fastidiousness of requirements should be treated as inviolable. The case for damages in nuisance – we are not concerned here with the question of an injunction – is made out if the interference is so pronounced and prolonged or repeated that a person of normal or average sensibilities should not be expected to put up with it. It is not necessary that an interference by objectionable smell should be so odious or damaging that it affects the plaintiffs’ health. It is enough if it can be said that a reasonable person in the plaintiffs’ circumstances should not be expected to tolerate the smell without requiring the defendants to make financial amends. I consider that the plaintiffs have made out such a case.
I would hold that each of the three plaintiffs has made out a case for damages for nuisance caused by offensive smells from the defendants’ factory.

7.	The complaint as to John Hanrahan’s health
It is the contention of the plaintiff John Hanrahan that the factory emissions seriously affected his health. The particular evidence as to this complaint must be considered against the background of the general evidence as to emissions from the factory.
The three main possible sources of atmospheric pollution caused by emissions from the factory are:-
1.A 120 ft. high chimney over a boilerhouse where heavy fuel oil is burned. The smoke from this chimney as an atmospheric pollutant is comparable to that emitted by chimneys in other industrial buildings where oil-fired boilers are used for heating or in power stations.
2.Certain exit points from the manufacturing or process building but more particularly what is referred to in the evidence as the scrubber stack.
3.The incinerator, a construction in which the waste chemicals are burned. Because the function of the incinerator is to effect the destruction by combustion of dangerous waste chemicals and solvents and because the incinerator was for significant periods in the years in question running at below its design temperature and therefore at a heat which was not adequate to destroy dangerous and contaminated solvents, it is marked out by the plaintiffs as the primary source of atmospheric pollution on their farm.
The evidence seems to me to show beyond doubt that atmospheric pollution in the neighbouring farms was caused by emissions from the factory. I have already dealt with the widespread complaints of offensive smells from the factory. There was also evidence from a variety of witnesses, which evidence went largely uncontroverted, of complaints such as a burning sensation in the throat and chest, reddening of the skin, irritation and streaming of the eyes and a smothering feeling in the nose, throat and chest. While complaints of that kind seem to have been experienced by different people in the area, the plaintiffs seem to be the only people who claimed that the atmospheric pollution affected their health. Whether or not the Hanrahan farm vis -a -vis the factory was in a special meteorological position, there was unimpeached independent evidence that the complaints of physical ill-effects in humans on the plaintiffs’ farm were matched by observable distress in the animals on the farm. In fact, the judge held that the evidence established that human and animal ill-health and unusual damage to plant life occurred on the plaintiffs’ farm in the relevant period. The only real question, therefore, is whether the judge’s finding of no causal connection between those complaints and emissions from the factory can be sustained.
Before dealing with the evidence of John Hanrahan and his medical advisers as to his ill-health, I think attention should be directed to the extent and variety of the evidence as to abnormalities on the plaintiffs’ farm as a consequence of pollution from the factory. Different witnesses described seeing clouds of emissions coming from the factory, feeling at such times discomfort and distress, noticing animals coughing and lowing and later finding unexplained abnormalities in the herd, and observing decay in plant life. Coupled with such evidence is the defendants’ admissions, supported by hundreds of complaints, that the emissions gave offence. Even if all the complaints made by or on behalf of the plaintiffs are not accepted, there were uncontroverted items of complaints which suggested that the factory emissions were at the root of the trouble. For example, John Hanrahan gave evidence that the ivy on the trees on the farm facing the factory withered. Evidence of that kind would lead one to expect complaints of human or animal ill-health.
John Hanrahan gave evidence to the effect that, after seeing clouds of emissions coming from the factory and experiencing foul smells and burning sensations on his skin and in his eyes and blisters on his tongue and on his head, his general health deteriorated. In particular he suffered from wheezing and pains in his chest. He attended his local general practitioner who referred him to a specialist.
The specialist was Dr. Muiris Fitzgerald, Professor of Medicine in University College, Dublin and a consultant in respiratory diseases in St. Vincent’s Hospital, Dublin. Professor Fitzgerald gave evidence that he
first saw John Hanrahan in 1980 when he found him suffering from wheezing and pulmonary obstruction which he then ascribed to either environmental pollution or asthma. Professor Fitzgerald admitted him to hospital for pathological and other tests in 1980 and again in 1982. A pathologist gave evidence that blood samples from John Hanrahan tested by him showed a condition known as mild hyperchloraemic acidosis. Another pathologist found a mild decrease in the white cell count in the blood which was consistent with poisoning by solvents.
Professor Fitzgerald having treated Mr. Hanrahan over a period of 4½ years from 1980, and having the benefit of pathological and haematological reports, gave evidence of his final opinion as to causation in the following terms:-

I would say that if it is shown that fumes, dusts, vapours, chemicals are present in the botanical life or animal life in the area, and if appropriate environmental meteorology in the evidence is compatible, and if it is shown that materials, acids, vapours are emanating from a source contiguous to the farm, then the balance of probabilities very much favours [the conclusion] that his lung disease can be attributed to a toxic substance.

That carefully worded opinion stood undisturbed at the end of the hearing by any contrary medical opinion. It meant, in the context of the other evidence in the case, that Professor Fitzgerald’s considered opinion was that, on the balance of probabilities, John Hanrahan’s lung disease was caused by toxic emissions from the factory, for that was the only local source of toxic substances.
Nevertheless, the judge held that John Hanrahan had failed to adduce sufficient evidence to support a finding that the factory was the source of his illness. The judge seems to have considered that Professor Fitzgerald’s opinion was overborne by the absence, unexplained, of evidence by John Hanrahan’s general practitioner and by the fact that evidence of similar complaints by other members of his family had not been given.
I am of opinion that the judge’s ruling was incorrect and was not supported by the evidence. The qualifications expressed in Professor Fitzgerald’s opinion were satisfied and there was no other opinion to the contrary. In those circumstances the opinion should have been accepted unless it appeared from the evidence as a whole that it was not worthy of acceptance. Neither of the two matters put forward as grounds for rejection of the opinion could properly be held to disestablish Professor Fitzgerald’s opinion. The likelihood is that Professor Fitzgerald’s opinion was given in the knowledge that none of John Hanrahan’s family had experienced similar symptoms and it does not appear to have been suggested to him in cross-examination that his opinion may have been weakened or invalidated by that fact. Neither could the absence of evidence by the general practitioner be treated as implying that such evidence, if given, would weaken Professor Fitzgerald’s opinion. It would be idle to speculate why the general practitioner was not called as a witness. The mere absence of such evidence could not, in my view, be treated as throwing any light on John Hanrahan’s previous medical history, particularly as when he was examined in December 1984 (by which time the nuisance had been abated) by a consultant physician acting on behalf of the defendants it was found that his chest condition was normal, thus indicating that he had not at the relevant time been suffering from any chronic pulmonary disorder.
I would hold that John Hanrahan is entitled to damages for the ill-health he suffered as a result of the nuisance caused by the factory emissions.

8.	The complaint as to Mrs. Mary Hanrahan’s health and Mrs. Selina Hanrahan’s health
Mrs. Mary Hanrahan did not give evidence of any specific form of ill-health alleged to have been suffered by her as a result of factory emissions. When asked in the witness box what was the ill-health she was blaming the factory for, she said: ‘I think my doctor will tell you that. I could not even tell you what it is’. In the event no doctor who had treated her was called to give evidence. Her complaint was therefore too vague and insubstantial to form the basis for an action in nuisance. The judge’s rejection of it cannot in my view be disturbed.
The judge also rejected Mrs. Selina Hanrahan’s complaint of ill-health. In January 1981 she was admitted to hospital in Waterford suffering from a uterine haemorrhage and was detained for seven days. She said that for the rest of that year she felt poorly, suffering from streaming eyes, sore nose and sore throat. In 1982 she was admitted to hospital twice, suffering from uterine haemorrhages. In September 1982 she underwent a hysterectomy, after which her general health seems to have improved. Having regard to the gynaecological nature of her complaints and the fact that there was no medical evidence to connect those complaints with factory emissions, it is not surprising that the judge rejected those complaints. I am at one with him in reaching that conclusion.

9.	The complaint of damage to plant life
Evidence was given by the plaintiffs Mrs. Mary Hanrahan and John Hanrahan of damage to certain plants, vegetables and flowers on the farm and this evidence was confirmed by a number of experts who considered air pollution by the factory to be the likely cause. The judge did not in his judgment specifically reject this evidence, but it is implicit that he did not consider that a case for damages for nuisance in this respect had been made out. While this evidence may be thought to support other complaints of damage by pollution from the factory, because of its vagueness as to the extent of damage caused or loss suffered, I find no reason to question the rejection of this evidence as a separate basis for an award of damage for nuisance.

10.	The nature and extent of the factory emissions
The main ground relied on by the plaintiffs for an award of damages for nuisance is the ill-effects suffered by the dairy herd on the farm as a result of the factory emissions. The defendants have sought to rebut that complaint in two ways: (1) by showing that the factory emissions were not such as to affect the health of the animals and (2) by showing that any ill-effects suffered by the animals were due to causes which were not factory-related.
It appears to be an unquestionable fact that the defendants’ factory is the main source of hydrogenchloride and hydrochloric acid mists in the Suir valley. The possible effects of such emissions have to be considered in terms of factors such as air chemistry, meteorology, the height of the factory chimneys, the configuration of the Suir valley, local meteorological features (such as the inversion by which air is trapped in the valley when winds are light) and the effect of prevailing winds. Readings taken at the points of emission in the factory are therefore not necessarily a sound guide as to the consequences of the emissions in different parts of the valley. For example, some of the emissions take place at levels below that of the valley floor, and the top of the scrubber stack is on a level with the ground floor of the plaintiffs’ house. The point has been taken that factory readings and the results shown by computer models do not take account of what actually happens in the Suir valley. The criticism has also been made that measurements of airborne concentrations on the plaintiffs’ farm give no more than an average daily concentration, thus leaving out short violent emissions and not taking into account the deleterious effect, particularly on grazing animals, of prolonged low-level emissions of gases and mists of unknown degrees of toxicity.
A considerable amount of scientific evidence was adduced at the trial as to the actual or possible effects of the factory emissions, and that evidence is summarised and carefully analysed in the judgment under review. I need not go through it because the judge held that ‘the only evidence in the case of measurements of toxic gases, vapours or other substances on the Hanrahan farm during the relevant period on which reliance can be placed is the evidence of Dr. Jameson’.
Dr. Jameson is a chemist employed by An Foras Forbartha who made reports in 1980 and 1982 on air pollution in the Ballydine area of Co. Tipperary, including the plaintiffs’ farm. His conclusions were based on a monitoring of ambient air concentrations. He found that the concentrations recorded were well within the guidelines used by many authorities.
Counsel for the plaintiffs have criticised those findings on a number of grounds, such as that they are based on fixed-time emissions only and that the standards applied are for humans rather than animals. Although the concentrations of acid vapours found on the plaintiffs’ farm by Dr. Jameson were said by him to be low, he agreed that they were 3½ times higher than those recorded on adjoining lands.
A consideration of the scientific evidence as a whole given on behalf of the defendants leads me to the conclusion that, even if accepted in full, it only shows what could or should have happened in the way of damage by toxic emissions. In the light of what did happen in the way of toxic damage, I consider that the defendants’ evidence could not be held to rebut the plaintiffs’ case. Theoretical or inductive evidence cannot be allowed to displace proven facts. It was proven as a matter of probability that John Hanrahan suffered ill-health as a result of toxic emissions from the factory. It was a fact, and so found by the judge, that there was unusual damage to some plant life on the plaintiffs’ farm in the relevant period, the only suggested source of this damage being the factory. And there was a volume of uncontroverted evidence given by eyewitnesses that animals were seen and heard to be ill and in distress at a time when the observer was experiencing foul chemical smells or weeping eyes or irritated skin, which could have been caused only by the factory. It would be to allow scientific theorising to dethrone fact to dispose of this claim by saying, as was said in the judgment under appeal, that there was ‘virtually no evidence in this case of injury to human beings or animals which has been scientifically linked to any chemicals emanating from the defendants’ factory’.
There are many factors which seem to me to render unacceptable the conclusion that it has not been proved as a matter of probability that the ill-health suffered by the animals was not caused by factory emissions. I instance the following four considerations:-
1.  The plaintiffs’ dairy herd was a thriving one up to the time when smells and other factory emissions were noticed.
2.   The five veterinary surgeons who regularly saw and treated the animals in the relevant period were all of the firm opinion that what the animals were suffering from was caused by toxic emissions from the factory.
3.   The factory incinerator, which was designed to burn, destroy or render harmless seven tons a day of chemical solvents was run for long periods at temperatures which were too low to achieve the    desired result, thus breaching one of the conditions of the planning permission for the factory and making damage to humans and animals highly likely.
4.  The ailments suffered by the cattle – evidenced by streaming eyes, coughing, a high incidence of abortions, twinning and of calves born deformed, reduced milk yields, sore and cut teats, stampeding, marked lack of thrift, and want of sexual capacity in the bulls – were too pronounced and varied to be accounted for by natural causes such as (as was suggested by the defendants) hoose or bad farm management. The most credible explanation offered for the ailments and abnormalities in the cattle was the toxic emissions from the factory.
I would therefore allow the appeal against the finding that the plaintiffs had not established as a matter of probability that the complaints about the condition of the cattle were not causally linked to toxic emissions from the defendants’ factory.

11.	The question whether the cattle ailments were due to causes other than factory emissions.
A considerable amount of evidence was given in the High Court on behalf of the defendants suggesting that the decline in the health of the dairy herd was due, not to toxic emissions from the defendants’ factory but to causes such as hoose or other animal ailments, or bad husbandry in the form of overstocking, inadequate culling, inbreeding, or poor silage and general farming practices. I have already held that the evidence established as a matter of probability that there was a causal relationship between the animal ailments and the factory emissions. What should have been in issue at the trial was whether the animal ailments were due entirely to the factory emissions. This question was never really addressed at the trial, for the case seems to have developed into a question whether the cause of the trouble was the factory or not. It is true that some of the defendants’ witnesses gave evidence suggesting that it was unlikely or impossible that factory emissions were the cause of the trouble. However, by the end of the case the question calling for an answer, particularly for the purpose of assessing damages, was whether the factory emissions were the sole cause of the animal complaints and consequently of the plaintiffs’ losses. The judge made no finding on this point because he discounted factory emissions as a cause of the plaintiffs’ complaints. All he held on this matter was that ‘there is clear evidence to indicate that the undoubted deterioration in the quality of the herd on the Hanrahan farm could have had other explanations [than the factory emissions]’.
In the circumstances it would not be proper for this Court to make the necessary findings as to the extent of causality which were not made in the High Court and which are a prerequisite to the assessment of damages in respect of the cattle. The hearing in the High Court dealt more with liability than damages. I consider that a further hearing in the High Court is necessary for the purpose of assessing damages and of making the findings necessary for such assessment.

12.	Conclusions
I would allow this appeal by the plaintiffs to the extent of holding that the three plaintiffs have established that the defendants are liable to them in damages for the offensive smells emitted from the factory, that John Hanrahan is entitled to damages for the injurious effect on his health of the factory emissions, and that the defendants are also liable in damages for the cattle ailments to the extent that they were caused by factory emissions. Since it is desirable that all the damages should, at least at first instance, be assessed by the same tribunal, I would remit the case to the High Court for both the assessment of the damages and the making of the findings necessary for such assessment.