Legal causation & apportionment Simon Morrow Partner, BLM Manchester business services construction & property insurance & indemnity leisure media & technology public sector retail transport Liability in disease cases The essential components are: The existence of a common law or statutory duty; A breach of that duty; and Damage resulting from the breach The ‘but for’ test Would the damage have occurred but for the defendant’s breach of duty? Balance of probabilities > 50% Damages in full Doubling of the relative risk Shortell v Bical Construction (2008) Lung cancer case Asbestos exposure Heavy smoker Attribution - Helsinki criteria - 25 fibre/ml years? ‘But for’ test satisfied Other tests Proof a scientific impossibility? ‘Material contribution’ ‘Material increase in risk’ / ‘Fairchild’ test ‘Material contribution’ Bonnington Castings v Wardlaw (1956) Innocent dust Guilty dust Disease Material increase in risk McGhee v NCB (1972) Wilsher v Essex AHA (1988) Fairchild v Glenhaven (2002) Wilsher v Essex AHA (1988) Risk factors Outcome Excessive O2 Risk 2 Risk 3 Blindness Risk 4 Risk 5 Contribution to risk Fairchild v Glenhaven (2002) Asbestos source 1 Mesothelioma Asbestos source 3 Asbestos source 2 The Fairchild conditions Mesothelioma - indivisible disease Multiple potential sources/culpable defendants Greater exposure increases the risk Each exposure alone potentially causative Science cannot show which exposure is to blame Fairchild extended? Barker v Corus Group (2006) Fairchild applied Liability limited to contribution to the risk Fairchild extended? Novartis Grimsby Ltd v Cookson (2007) Bladder cancer Occupational exposure 70-75% of increased risk ‘But for’ test satisfied Fairchild test highly arguable Fairchild extended? Sanderson v Hull (2008) Bacterial infection Contracted at work/elsewhere? Fairchild test not applicable ‘But for’ test not satisfied Apportionment Divisible diseases - yes: NIHL - Thompson v Smith’s Shiprepairers (1984) Asbestosis - Holtby v Brigham & Cowan (2000) HAVS – Allen v British Rail Eng. (2001) Apportionment Indivisible diseases: Depends on test applied? Contribution to risk - Barker v Corus (2006) But for / material contribution: • Ellis v Environment Agency (2008) • Bailey v MoD (2008) Apportionment Dickens v O2 (2008) Occupational stress Material contribution sufficient 50% reduction for non-tortious factors Psychiatric injury indivisible?