Transco Plc v Griggs

A claimant may prove medical causation on the balance of probabilities by diagnosis by exclusion where other possible causes have effectively been excluded and the remaining occupational cause is not improbable. This reasoning does not reverse the burden of proof or commit the Holmesian fallacy.

Where prolonged vibration exposure, admitted failures in prevention and detection, and medical causation are established, the ordinary but for test may establish legal causation. Alternatively, an employer’s failure to maintain a proper protective system which materially increases the risk of a vibration-induced disease may justify liability where strict causal proof is unavailable.

The claimant had worked for the defendant as a distribution fitter for 24 years, routinely using heavy vibratory tools. The defendant admitted breaches of duty in its system for preventing and detecting vibration-induced disease. Although initially diagnosed with hand-arm vibration syndrome, further investigation established that the claimant suffered from palmar arch disease, a rare vascular condition.

His Honour Judge Darroch in the Norwich County Court found that the condition had probably been caused by workplace vibration and entered judgment for the claimant. The employer appealed, challenging medical causation and, secondarily, whether negligent rather than acceptable vibration exposure had legally caused the injury.

Disposition

1. The appeal was dismissed. Lady Justice Hale held that the county court judge was entitled to find both medical and legal causation. Wilson J agreed.
2. Medical causation: The evidence justified the finding that workplace vibration had probably caused the palmar arch disease. A trial judge deciding between experts must assess the reliability of their opinions. Qualifications and experience matter, but the quality of the evidence and reasoning is most important. The claimant’s vascular expert had excluded the recognised alternative causes and had given a plausible mechanism by which prolonged vibration could damage the palmar arches.
3. The absence of scientific proof or strong published literature did not prevent proof on the civil standard. Diagnosis by exclusion was legitimate in this case. It did not reverse the burden of proof because vibration was a possible, rather than an improbable, cause and the other possible causes had effectively been excluded. The reasoning was therefore distinguishable from the Holmesian fallacy explained in Rhesa Shipping SA v Edmunds, The Popi M [1985] 1 WLR 948.
4. Legal causation: The ordinary but for test was satisfied. The claimant’s substantial and prolonged exposure, the admitted systemic breaches, and the exclusion of other causes permitted the conclusion that the negligence had caused the injury. It was unnecessary to apportion damage between negligent and non-negligent exposure under Allen v British Rail Engineering Ltd [2001] PIQR Q101, since that issue had not been put to the judge.
5. In the alternative, even if strict but for proof had not been possible, the failure to operate a proper system materially increased the risk of a vibration-induced disease. That was sufficient under the material-increase-in-risk approach associated with McGhee v National Coal Board [1973] 1 WLR 1 and Fairchild v Glenhaven Funeral Services Ltd [2003] 1 AC 32.

• Court of Appeal (Civil Division) — dismissed the employer’s appeal and upheld judgment for the claimant: [2003] EWCA Civ 564.
• Norwich County Court — His Honour Judge Darroch gave judgment for the claimant on 22 August 2002. Judgment was entered on 7 October 2002 for £211,149.