Legal causation and apportionment Simon Morrow Partner, BLM Manchester Birmingham Cardiff Leeds Liverpool London Manchester Southampton Stockton-on-Tees
Legal causation in disease cases Introduction As with any other type of personal injury, the onus is on the claimant in an occupational disease claim to show, on the balance of probabilities, a causal connection between the defendant s breach of duty and the claimant s loss. Proof of causation by the traditional but for test means that the claimant has to show that his injury would not have occurred but for the defendant s breach of duty. This can prove very difficult or even impossible in relation to certain occupational disease claims where applying the but for test would involve precisely quantifying the proportions in which competing agents contributed to the onset of the disease. For example, assume that, in breach of their duty of care, two or more people cause the claimant to be cumulatively exposed to harmful dust, which results in the onset of a disease in respect of which the greater the exposure to dust, the worse the disease is likely to become (eg silicosis). The claimant (because of scientific uncertainty) will probably not be able to show that his injury would not have occurred but for the first defendant s negligence, or the second defendant s negligence, and so on. As a result, for policy reasons, the courts have relaxed the strict rules of causation in occupational disease cases. Thus in certain cases, it will be enough for the claimant to establish that a breach of duty on the art of the defendant has merely materially contributed to or even simply materially increased the risk of the claimant s condition. However, as with other types of personal injury, the defendant in an occupational disease claim will not necessarily be held responsible for all losses that are connected to his breach of duty. For instance, the defendant will not be held responsible for losses that are too remote, that relate to an intervening cause, or that arise because the claimant has failed to mitigate his loss. The but for test in disease cases Although the relaxation of the causation rules means that there are other causation tests in relation to occupational disease, the but for test continues to apply in appropriate cases. The claimant in Novartis Grimsby Ltd v Cookson [2007] EWCA Civ 1261 had developed bladder cancer which he alleged was due to negligent exposure to carcinogenic aromatic amines whilst working at the defendant s dyestuffs factory. Smoking can also be a cause of bladder cancer and the claimant had been a moderate smoker for 20 years. The claimant s medical evidence (which was accepted by the recorder who heard the case at first instance) indicated that the claimant s occupational exposure had contributed 70-75% of the total risk of him developing bladder cancer whilst the claimant s smoking had contributed 25-30%. The recorder thus concluded, by applying Bonnington Castings v Wardlaw [1956] AC 613 (see below), that the claimant succeeded by virtue that he had established that the occupational exposure had made a material contribution to the risk of him developing bladder cancer. The defendant appealed on the basis that it had been wrong for the recorder to cite and apply Wardlaw. The Court of Appeal agreed. Nevertheless, the appeal failed. The recorder was entitled to prefer the expert evidence adduced on the part of the claimant that occupational exposure accounted for at least 70% of the total risk and more than doubled the risk due to smoking. Having done so, the natural inference to be drawn was that the claimant would probably not have developed bladder cancer had it not been for the occupational exposure. The but for test was therefore satisfied. Legal causation and apportionment_sgm_0909 1
Material contribution to injury As already stated, the claimant in a disease claim does not necessarily have to prove that the defendant s breach of duty was the sole or even the main cause of his damage, provided he can show that it made a material contribution to the damage. The House of Lords looked at the position of a claimant who could not satisfy the but for test because the damage resulted from the cumulative effect from two sources in Bonnington Castings v Wardlaw [1956] AC 613. The claimant worked in a dressing shop in a foundry. He developed pneumoconiosis from inhaling silica dust. The claimant was exposed concurrently to dust from swing grinders, which the defendant should have prevented, and dust from pneumatic hammers, which was innocent exposure. The claimant could not show which exposure had caused his pneumoconiosis. The House of Lords concluded that the question to be answered was whether the dust from the (guilty) swing grinders materially contributed to the disease. The Lords drew an inference of fact that the guilty. dust from the swing grinders was a contributory cause and held the defendant liable for the full extent of the claimant s loss notwithstanding that the innocent exposure had been greater than the guilty exposure. Material contribution to the risk of injury This material contribution principle has been further developed by a series of cases commencing with McGhee v National Coal Board [1972] 3 All ER 1008, in which the House of Lords allowed a claim where the defendant s negligence had materially contributed to the risk of the claimant contracting dermatitis following exposure to brick dust. The claimant was innocently exposed to brick dust during his job but in breach of duty his employers failed to provide washing facilities so that the claimant was left with the dust on his skin whilst he cycled home from work. Medical evidence established that brick dust had caused the condition but it was impossible to prove that the additional exposure whilst travelling home had made any difference. At best, it could only be said that the failure to provide washing facilities materially increased the risk of the claimant contracting dermatitis. A majority of the Lords treated a material increase in the risk as equivalent to a material contribution to the damage. This decision was later clarified in Wilsher v Essex Area Health Authority [1988] AC 1074, a medical negligence claim made on behalf of a premature baby who suffered from an incurable retinal condition. The defendant s negligence was only one of 5 possible causes of the injury, none of which were more likely than the others. Whilst the claimant attempted to argue that the defendant s negligence increased the risk of the condition, the House of Lords held that the burden of proving the causal link lay with the claimant and no causative link could be inferred. The decision in McGhee was revisited in the House of Lords judgment in Fairchild v Glenhaven Funeral Services [2002] UKHL 22. The House heard appeals arising out of three separate cases, all with similar facts. The claimants had all contracted mesothelioma from exposure to asbestos dust at work. Each had been wrongly exposed to asbestos by more than one employer over several years but, because of the gaps in scientific knowledge about the aetiology of their condition, was unable to show which period of exposure had caused him to contract the disease. Despite this problem, the claimants were awarded damages for their injury. The Lords felt that the decision in Wilsher had been correct on its facts but that McGhee had been incorrectly interpreted in Wilsher. It was decided that if certain preconditions were met, proof that negligent conduct increased the risk of an injury was sufficient to establish the causal requirement in respect of liability. The Fairchild exception applies where there are multiple defendants in breach of a similar duty because it would be unfair or unjust as a matter of policy to deprive a claimant of compensation simply because he is unable to prove the impossible. Because this involves a relaxation of the relevant causation rules, the House of Lords stressed that there were strict limits to the application of this exception. Legal causation and apportionment_sgm_0909 2
The specific conditions stated in establishing liability in Fairchild can be summarised as follows: a. the employee was employed by two or more employers at different times and for different periods; b. the employers were each subject to a duty specifically intended to protect employees against being unnecessarily exposed to the risk of a particular disease; c. the employers were each in breach of this duty in relation to the employee during the periods for which they employed the employee; d. the duty is intended to create a civil right to compensate for the breach; e. the greater the exposure to asbestos, the greater the risk of contracting the disease; f. the employee contracted the disease against which he should have been protected; g. any cause of the employee s disease other than exposure to asbestos at work can be effectively discounted; h. the limits of medical science mean that the employee cannot prove on a balance of probabilities which asbestos exposure is more likely than not to have produced the cell mutation which caused the disease. Causation since Fairchild Predictably, there has subsequent to Fairchild been a number of attempts by claimants to persuade courts to extend the application of the Fairchild exception. As Lord Hoffman described it in Barker v Corus (UK) plc [2006] UKHL 20, It is only natural that, the dyke having been breached, the pressure of a sea of claimants should try to enlarge the gap. These efforts have in the main been resisted by the judiciary. An attempt to extend the application of the Fairchild test to a medical negligence claim was narrowly rejected in Gregg v Scott [2005] UKHL 2; [2005] 2 AC 176, whilst the Court of Appeal also refused to apply the test to an accident involving a catastrophic injury in Clough v First Choice Holidays [2006] EWCA Civ 15 on the basis that it involved an individual, specific occasion of negligence and therefore did not satisfy the specific conditions set out in Fairchild. There is a good illustration of this judicial reluctance in Lord Hoffman s judgment in Barker, in which he stated that in his view, there were two additional conditions that were essential for the application of the less stringent material increase in risk test, namely that: (a) (b) it is impossible to prove any more stringent test other than increase in risk; and the injury is caused by a sole causative agent (eg brick dust or asbestos). Although not being required to do so in the circumstances of the Novartis case (see above), Lady Justice Smith proceeded to postulate in her judgement in that case that the Fairchild exception is not restricted to mesothelioma and it is highly arguable that it should also apply to bladder cancer, since in such a case, the amines in the cigarette smoke and in the dyes operate in the same way. Such a position does not fall foul of Lord Hoffman s comments in Barker, as the bladder cancer situation would differ from a lung cancer case where smoking and asbestos exposure different agents acting in different ways - might each have contributed to the risk. The present application of the decision in Wardlaw was also discussed by Lady Justice Smith in Novartis. She queried whether it only applied to divisible conditions (where the various Legal causation and apportionment_sgm_0909 3
exposures contribute only to the severity of the disease) rather than those cases where the various exposures contribute only to the risk that the disease will develop. She failed to answer her own question in that case, but the acceptance of proof of material contribution in subsequent cases suggests that it potentially still applies in respect of both divisible and indivisible conditions, subject to the proviso that it is impossible for the claimant to prove causation by means of the but for test. In Shortell v Bical Construction Ltd QBD 16.5.2008 (unreported), Mr Justice Mackay was required to deal with a case of lung cancer allegedly due to asbestos exposure. The deceased, who died in 2006, had worked as a cable jointer in power stations between 1953 and 1976 and had been intermittently exposed to asbestos from working in the vicinity of laggers. Breach of duty was conceded but causation was in issue. Evidence from the deceased was somewhat vague as to the extent and duration of his asbestos exposure. The deceased had also been a smoker. The claimant argued that the deceased had during his many years working for the defendant sustained a cumulative exposure in excess of 25 fibres/ml-years, thus satisfying one of the Helsinki criteria for the attribution of lung cancer to asbestos exposure. The claimant relied on an expert engineer who, having made various assumptions regarding the intensity and duration of the exposure, estimated the exposure at 99 fibres/ml-years. The defendant s expert evidence was that this estimate was speculative, that no analogy could be drawn from the historical material that the claimant s expert engineer relied upon and that, in any event, the Helsinki criterion of 25 fibres/ml-years was too low. The judge preferred the claimant s expert evidence. On the basis that the deceased s asbestos burden whilst employed by the defendant had been 99 fibres/ml-years, his asbestos exposure had more than doubled the relative risk that he would develop lung cancer. Thus, the deceased had established that he would not have developed his lung cancer had he not been exposed to asbestos. Causation was therefore satisfied without the need for resort to the Fairchild test. There was a deduction of 15% for contributory negligence for the deceased s smoking notwithstanding the absence of any evidence that the deceased had been told by his doctor to stop. Bailey v The Ministry of Defence [2008] EWCA Civ 883 was another clinical negligence case involving consideration of proof of causation. The claimant had sustained brain damage after she had inhaled vomit and consequently suffered cardiac arrest. She had inhaled her vomit because she was too weak and debilitated to naturally protect her airway. The judge at first instance accepted that the physical cause of her weakness and therefore her inability to react to her vomit was a combination of her negligent post-operative care at a hospital managed by the MoD and what flowed from that and her pancreatitis, a non-negligent cause, and therefore, as the defendant s negligence in treating the claimant had made a material (ie more than negligible) contribution to the injury, the claimant was entitled to succeed in full. The MoD appealed on the grounds that there was no evidence linking the lack of care with the occurrence of the vomiting and aspiration and also that, relying on Wilsher, it was not enough if the claimant merely established that its lack of care made a material contribution to the claimant s injury, the correct test for causation was the but for test. The Court of Appeal decided that as this was a case where cumulative causes acted so as to create the weakness and the inadequacies of medical science could not establish the probability that but for an act of negligence the injury would not have happened, the but for test was modified. Since the claimant had established that the contribution of the negligent cause was more than negligible, the claim succeeded. Accordingly, the judge had applied the right test in this case and was entitled to reach the conclusion that he had reached. Lord Justice Waller also considered that it was not appropriate to draw a distinction between medical negligence and other cases in this respect. If the case involves cumulative causes and it is not scientifically possible to establish the probability that but for an act of negligence, the injury would not have happened, the but for test should be modified and, provided it can be Legal causation and apportionment_sgm_0909 4
established that the contribution of the negligent cause was more than negligible, the claim should succeed. The ambit of the Fairchild exception was again considered by the Court of Appeal in Sanderson v Hull [2008] EWCA Civ 1211. The claimant was a plucker employed at the defendant s turkey farm who suffered a bacterial infection which she alleged arose from touching her mouth with her contaminated hands. Whilst the risk of infection from such work had been known for some years, the defendant had allowed the claimant to work without gloves and had provided no instruction on precautions to be taken, such as not touching her face. The parties experts agreed that the bacteria was commonly found in poultry but was also commonly found elsewhere. They could not agree on whether the claimant had been infected at work. The defendant denied both breach of duty and causation, arguing that regular hand washing was the only way to reduce the risk of infection, suitable washing facilities had been provided and it was commonsense not to touch one s face after handling turkey carcasses. The recorder who heard the case at first instance held the defendant liable on the basis that the case fell within the Fairchild exception and since the defendant s breaches of duty materially increased the risk of infection, causation was established. The defendant appealed, submitting that the Fairchild exception did not apply to this case. The Court of Appeal stressed that whilst great caution was required before any development of the exception to the but for test should be allowed, the conditions set out in Fairchild in relation to mesothelioma which might justify the relaxation of the test were not intended to exclude the application of the exception to other diseases and circumstances. However, an essential element for the extension of the exception was that there was some other exposure (in addition to that caused by the defendant s fault) which could have been a potential cause of her injury. It also had to be scientifically impossible to prove enough to satisfy the but for test: mere difficulty of proof would not be enough. The recorder's difficulties in reaching a conclusion on causation were created not by any impossibility of proof but by his failure to properly analyse the facts relating to negligence and causation and to make crucial findings of fact. If the necessary findings of fact had been made, he would have been able to make a decision on the usual but for basis. Accordingly, the recorder was wrong to hold that the case fell within the Fairchild exception and the recorder s decision was overturned. Occupational stress The causal link is generally regarded as more difficult to establish in cases involving alleged occupational stress. The following difficulties were highlighted by the Court of Appeal in Hatton v Sutherland [2002] EWCA Civ 76: all occupations involve some element of stress and it can be difficult to anticipate which employees are foreseeably likely to develop psychiatric damage due to stress; there are no occupations which are inherently dangerous to mental health, since it is the interaction between the individual and the job in question rather than the job itself that causes the harm; there are many other stress factors in ordinary life other than work which can affect an employee s mental health and can contribute to mental breakdown, for instance illness, divorce and bereavement; the claimant must demonstrate that the psychiatric illness is not due to simply stress at work but that it was the employer s specific breach of duty that caused the damage. In other words, proof of a psychiatric condition together with a stressful working environment is not sufficient to establish a causal link (although of course, applying Legal causation and apportionment_sgm_0909 5
Wardlaw, the claimant does not have to prove that the employer s breach of duty was the sole cause of his mental illness, merely that it made a material contribution). The case of Dickins v O2 Plc [2008] EWCA Civ 1144 concerned a former secretary who had progressed through the ranks to the position of finance manager. She had a previous history of non-employment related anxiety/depression. She found her work stressful. In March 2002, she spoke to her manager about moving to a less stressful job and told him that she had too much work, whilst in April 2002 she told her manager that she was stressed out and requested a six months sabbatical. At her annual appraisal the next month, the claimant told her manager that she still felt very stressed. A few days after the appraisal, she felt unable to go into work. She then attempted to return to work in June 2002, but her GP signed her off as unfit for work on account of anxiety and depression. She never returned to work with the defendant and her employment was terminated in November 2003. In finding for the claimant, the trial judge decided that the defendant had breached its duty of care by failing to respond appropriately following the complaints made by the claimant at the meeting in April 2002. He also held that the defendant s negligence had made a material contribution to the claimant s injury. However, he found that there were relevant non-tortious factors - the claimant had a psychologically vulnerable personality and problems in her home life - and he therefore apportioned damages half and half between the defendant s breach of duty and the non-tortious factors. Upon the defendant s appeal, the Court of Appeal confirmed that the correct test for causation was as propounded by Lady Justice Hale (as she then was) in Hatton so that the employee does not have to show that the breach of duty was the whole cause of his ill-health, it is enough to show that it made a material contribution. It was clear from the judge s findings and the psychiatric evidence that although there were other causal factors, the defendant s breach of duty had made a material contribution to the claimant s illness. Looking at the factual background, the obvious inference was that the claimant tipped over the edge because nothing significant had been done to recognise and address her need for a rest and for a change to her work requirements. Conclusion The current situation as regards causation in occupational disease cases was covered by Waller LJ in his judgment in Bailey, in which he said: I would summarise the position in relation to cumulative cause cases as follows. If the evidence demonstrates on a balance of probabilities that the injury would have occurred as a result of the non tortious cause or causes in any event, the claimant will have failed to establish that the tortious cause contributed.if the evidence demonstrates that 'but for' the contribution of the tortious cause the injury would probably not have occurred, the claimant will (obviously) have discharged the burden. In a case where medical science cannot establish the probability that 'but for' an act of negligence the injury would not have happened but can establish that the contribution of the negligent cause was more than negligible, the 'but for' test is modified, and the claimant will succeed. Lady Justice Smith s analysis in Sanderson of what each member of the House of Lords said in Fairchild indicates that the Fairchild exception is not necessarily confined to mesothelioma. This is supported by the fact that it had its origins in McGhee, a dermatitis case. However, on the basis of the conditions laid down in Fairchild and Barker and the refusal to accept a material increase in risk in Clough and certain medical negligence cases (including Wilsher), it would now appear settled that the operation of the material increase in risk test will be restricted to a limited number of occupational disease and clinical negligence claims. Legal causation and apportionment_sgm_0909 6
Apportionment in disease cases Introduction The only question the defendants asked the court in Wardlaw and McGhee was whether they were liable at all, they never asked to what extent they were liable. Apportionment was not even raised in Fairchild. It is only relatively recently that courts have started to provide an answer to the question of apportionment in occupational disease cases. This question arises if there is: two or more tortfeasors (as in Fairchild); two or more causative agents (say asbestos dust and smoking, as in Shortell); two or more sources of the same harmful agent, at least one involving culpability and at least one not (as in Wardlaw and McGhee); periods of both culpable and non-culpable exposure (as in Thompson, below); two or more contributing insurers; and/or a period or periods of insurance and an uninsured period or periods. This paper will attempt to cover all but the last two situations. Apportionment between insurers is generally governed by the terms of the Industrial Disease Claims Working Party Agreement. It is firstly necessary for a defendant to raise apportionment as an issue, whereupon the court s approach to the issue will generally depend upon whether the disease is divisible or indivisible. The question of whether a disease is divisible or indivisible is strictly speaking a question of fact in each case. The medical expert or experts should be asked in a relevant case whether or not apportionment is possible and if so, to express their opinion as to the appropriate apportionment in the circumstances. Experience has indicated that work related upper limb disorders, asthma and mesothelioma are examples of indivisible conditions, whilst noise induced hearing loss, hand/arm vibration syndrome, asbestosis and pleural thickening are divisible conditions. Going forward, as there are advances in scientific knowledge, it maybe that conditions presently thought of as indivisible can in future be treated as divisible. Divisible conditions These are conditions where there is a dose-response relationship between the exposure and the severity of the disease and scientific knowledge enables the experts to measure or assess the extent to which the particular exposure is responsible for the claimant s condition. In respect of diseases that are divisible, apportionment will generally be allowed in terms of periods of time and between tortfeasors (and innocent parties), separate causative agents and different sources of the cause of harm. In Thompson v Smith s Shiprepairers (North Shields) Limited [1984] Q.B. 405, the claimant suffered hearing loss due to exposure to excessive noise at work. The defendants were held liable only for that part of the hearing loss which occurred after the exposure to noise became a breach of duty. Although the claimant s deafness was probably entirely work-related, the defendants were not liable for that element of the deafness which occurred before they should have taken reasonable precautions to protect the claimant, which was established in this case as 1963. At this point, the claimant s hearing was already damaged and therefore the Legal causation and apportionment_sgm_0909 7
defendants were liable only for the additional damage caused by their breach of duty. Mustill J (as he then was) explained his reasoning as follows:... I see no reason why the present impossibility of making a precise apportionment of impairment and disability in terms of time, should in justice lead to the result that the defendants are adjudged liable to pay in full, when it is known that only part of the damage was their fault. What justice does demand, to my mind, is that the court should make the best estimate it can, in the light of the evidence, making the fullest allowances in favour of the plaintiffs for the uncertainties known to be involved in any apportionment. In Holtby v Brigham & Cowan (Hull) Limited [2000] 3 All E.R. 421, the claimant had been exposed to asbestos dust in the course of his work as a marine fitter for a period of almost 40 years. For about half of that time he worked for the defendant and for the remainder he worked for other employers doing the same sort of work in similar conditions, in some cases for many years and in others for a matter of months. He developed asbestosis for which the defendant was held to be liable. However, the evidence indicated that if the claimant had only been exposed to asbestos whilst working for the defendant, his condition would probably have been less severe. The judge held that the defendants were only liable for the damage they had caused and reduced the general damages awarded by 25%. The Court of Appeal rejected the claimant s appeal on the basis that the burden of proof was on the claimant that the defendant was liable for all of his loss rather than the extent of its contribution and that the claimant had not discharged this burden on this occasion. In Allen v British Rail Engineering Limited [2001] PIQR Q101, the claimant claimed in respect of hand/arm vibration syndrome (more commonly known as vibration white finger ) caused by his use of hand-held vibratory tools at work. The damages awarded to the claimant were reduced to take account of the fact that, on the evidence, the exercise of reasonable care by the defendant would only have reduced the claimant s exposure by about one-half. The employer s liability was limited to the extent of the contribution which its tortious conduct made to the disability, even though the remaining damage was caused by the defendant s innocent conduct and the extent of the damage was aggravated by its tortious conduct. The following points of principle for divisible condition cases were set out by the Court of Appeal in Allen: a. the claimant will establish liability if he can prove that the defendant s breach of duty has made a material contribution to the claimant s injury; b. there can be cases where the state of the evidence is such that it is just to recognise each of two separate tortfeasors as having caused the whole of the claimant s injury, but in principle, a defendant s liability is limited to the extent his breach of duty contributed to the claimant s disability; c. the court must do the best that it can on the evidence to make an apportionment of liability, but a claimant s case should not fail if he cannot accurately establish the proportion of the injury attributable to each defendant; d. evidence to prove apportionment must be proportionate to the amount at stake and the uncertainties inherent in making an award of damages for personal injury. There will be cases however in respect of even a divisible condition where apportionment does not apply. In the case of Smith v Wright & Beyer Limited [2001] EWCA Civ 1069, the trial judge found that the claimant had been exposed to vibration since 1961 but that only exposure from 1977 was culpable. However, the claimant s relevant symptoms did not materialise until the mid- 1980s. The medical evidence indicated that as a consequence of the claimant s reservoir of tolerance to vibration, the claimant would probably never have gone on to develop HAVS Legal causation and apportionment_sgm_0909 8
symptoms had the defendant complied with its duty to the claimant from 1977. In the circumstances, the judge refused to make any reduction in the claimant s damages for innocent exposure. His approach was upheld by the Court of Appeal. Indivisible conditions Mesothelioma is regarded as indivisible (on the basis that it is not scientifically possible to calculate the extent of the contribution to the condition caused by the breach of duty). As already stated, apportionment was not argued in Fairchild, but the issue was considered by the House of Lords in terms of mesothelioma in Barker. Mr Barker had died of asbestos-related mesothelioma. He had had three material exposures to asbestos during his working career. The first two were in consequence of breaches of duty by separate employers, one of which being the defendant. The third exposure was whilst he was working as a self-employed plasterer and involved a failure to take reasonable care for his own safety. A key aspect of the decision in Fairchild to allow the claimants to recover was that the injustice of denying redress to a victim heavily outweighed the injustice in imposing liability on a duty breaking employer whose wrongdoing may not have been responsible for the claimant s illness. This was accepted as rough justice and it was recognised in Barker that the injustice could be diminished by an apportionment of the liability. As Lord Hoffman put it: In my opinion, the attribution of liability according to the relative degree of contribution to the chance of the disease being contracted would smooth the roughness of the justice which a rule of joint and several liability creates. The defendant was a wrongdoer, it is true, and should not be allowed to escape liability altogether, but he should not be liable for more than the damage which he caused and, since this is a case in which science can deal only in probabilities, the law should accept that position and attribute liability according to probabilities. The justification for the joint and several liability rule is that if you caused harm, there is no reason why your liability should be reduced because someone else also caused the same harm. But when liability is exceptionally imposed because you may have caused harm, the same considerations do not apply and fairness suggests that if more than one person may have been responsible, liability should be divided according to the probability that one or other caused the harm. This approach has of course been reversed by the provisions of The Compensation Act 2006, but only so far as mesothelioma is concerned. The Barker approach should still be followed in the event that the Fairchild exception is applied to any disease other than mesothelioma. But is there apportionment in indivisible cases dealt with by the application of the but for test or on the basis of material contribution? There are conflicting indications in respect of psychiatric injury, which is generally regarded as indivisible. There is support for apportionment between tortfeasors in cases of psychiatric injury as a result of the decision of the Court of Appeal in Rahman v Arearose & Others [2001] QB 351. The claimant in Rahman was the manager of a branch of Burger King in King s Cross. He was in the course of his employment assaulted by two black youths who were members of a violent gang that had previously attacked the claimant and other staff at the premises. The claimant was as a result of the injuries sustained taken to hospital, where he underwent a botched operation that led to the permanent loss of vision in his right eye. His employer agreed to be 60% liable for having failed to take adequate measures to protect its staff given the previous assaults, whilst the hospital admitted full liability for the negligence on the part of its eye surgeon in relation to the operation. In assessing damages, the judge took a different approach in respect of general and special damages. In respect of general damages, he assessed 7,500 as against the employer and Legal causation and apportionment_sgm_0909 9
55,000 as against the hospital. In relation to the remaining heads of damages, he assessed the entirety of these at just in excess of 500,000 and apportioned this figure as to one-third to the employer and two-thirds to the hospital on the grounds of a combination of causative potency and respective blameworthiness. The employer appealed, arguing that the judge should not have apportioned the damages for past and future losses between the defendants on a percentage basis; rather it should only bear liability for those losses directly caused by the assault. The principal question on appeal was the interrelation of the assault and the clinical negligence in relation to causation of the psychiatric injury. The Court of Appeal, whilst effectively approving the judge s general approach, adjusted the awards for past and future losses to one-quarter and three-quarters respectively in order to reflect the relative responsibility of the defendants as assessed on the facts. The court accepted that the role of the fact-finding court was to arrive at a just conclusion on the evidence as to the respective damage caused by each defendant, even if it could only do it on a broad-brush basis which then had to be translated into percentages. Laws LJ justified the apportionment of what most would have regarded as indivisible in these terms: where it is shown that (a) each tortfeasor caused some part of the damage, but (b) neither caused the whole, and (c) some part (but not all) of the damage would therefore have been occasioned to the claimant if only one tort - either of them - had been committed, but on the evidence it is impossible to identify with any precision what part or element of the damage had been caused by which defendant it would plainly be unjust to proceed on the footing that a defendant is responsible for the whole of the claimant's damage when, demonstrably, he is not. In other words, even the indivisible could and should be divided in assessing damages. This decision was referred to in Hatton, where the guidance provided was that an attempt at apportionment should be made in psychiatric injury cases where the injury has more than one cause. However, the approach is incompatible with other recent decisions. In The Environment Agency v Ellis [2008] EWCA 1117, the claimant had suffered a back injury when he fell at work in June 1998. He then suffered a second injury at work in May 1999 when he missed his footing on a ladder. In April 2000, whilst at home, the claimant s back gave way, causing him to fall and injure his knee. The claimant had pre-existing, undiagnosed, symptomless spinal degeneration, greater than expected in a man of his age and which would have got worse over time, irrespective of the accidents. The claimant alleged that the defendant was liable for the June 1998 accident. He also claimed that the April 2000 fall (resulting in the knee injury) was a consequence of the June 1998 back injury. He argued that the June 1998 accident triggered symptoms in his back 10 years earlier than they would have done had the accident not happened. The judge at first instance awarded the claimant 90% of his loss, having concluded that the June 1998 accident caused the back problems which led to the April 2000 fall and that, but for the June 1998 accident, the April 2000 fall would not have happened. The judge s quantification of damages was adjusted to take account of the medical evidence that the claimant would have experienced back problems after about 10 years and serious disability after 20 years in any event. The total damages award was reduced by 10% to take account of the contribution to the deterioration of the claimant s back made by the May 1999 accident. The defendant appealed on the basis that there should have been apportionment between three causes as follows: the pre-existing spinal degeneration (70%), the June 1998 accident (20%) and the May 1999 accident (10%), and that as the defendant was only responsible for the Legal causation and apportionment_sgm_0909 10
second of these, the claimant should only recover 20% of his loss. The defendant relied chiefly on the decisions in Holtby and Allen. The claimant cross-appealed on the basis that he was entitled to 100% of his loss. The Court of Appeal considered that apportionment should not apply. It was stated that the but for test is the normal rule for causation in personal injury cases and should be applied. The principles stated in Holtby and Allen were referred to as an exception to the general rule whose application should be limited to disease or injury cases where there has been successive exposure to harm by a number of agencies, where the harm is divisible and where it was unjust for the defendant to bear the whole of the loss when he was not responsible for all of it. Here, the main injury (in April 2000), although contributed to by the May 1999 accident, was a single indivisible event and the injury could not be apportioned merely because the expert attributed a small causative percentage to the May 1999 accident. It could not be apportioned in the way that successive causes over a number of years in an industrial injury case could be apportioned. The claimant was thus entitled to 100% of his damages. There was also no apportionment to take account of the non-negligent pancreatitis in Bailey (referred to earlier). In the case of Dickins (also referred to earlier), both Lady Justice Smith and Lord Justice Sedley considered that a psychiatric injury with more than one cause was indivisible and damages should not be apportioned. Smith LJ found little difference between Dickins and Bailey. As in Bailey, the defendant s breach had made a material contribution to the injury but it was not possible to say that, without the breach, the claimant would have suffered the injury. She said that once a claimant has shown that the defendant s negligence has materially contributed to the injury, the defendant will be liable for all the damage suffered. Sedley LJ stated that courts at first instance should at least for the present follow Bailey rather than Hatton. Conclusion There appears to be no question that apportionment should be undertaken in respect of divisible conditions, provided that it has been raised as an issue. In these cases, it is advisable to obtain medical evidence to enable the court to deal with the issue. So far as indivisible diseases are concerned, if the claimant succeeds with his claim on the basis of the but for test or the tort has made a material contribution, the current thinking seems to be that damages should not be apportioned, although the position is not absolutely clear. That part of the judgment in Dickins dealing with non apportionment is obiter (as is the Hatton guidance in relation to apportionment) and it remains to be seen whether courts will continue to follow Hatton or will now prefer the approach in Bailey. It is advisable whilst uncertainty remains to continue to raise apportionment as an issue and to seek medical evidence supporting this if possible. Apportionment remains appropriate in mesothelioma cases where the relevant parties are before the court but not otherwise, whilst the approach indicated in Barker should be followed in the event that the Fairchild exception is applied to any disease other than mesothelioma. Berrymans Lace Mawer LLP 2009 Disclaimer This document does not present a complete or comprehensive statement of the law, nor does it constitute legal advice. It is intended only to highlight issues that may be of interest to clients of Berrymans Lace Mawer. Specialist legal advice should always be sought in any particular case. Information is correct at the time of release. Legal causation and apportionment_sgm_0909 11