#7168 - Causation - Torts B

P bears the burden of proving factual and legal causation (that D’s acts contributed in a real or material way to the harm to P) on the balance of probabilities (OBP) (WA s 52).

1. Proof by inference (that the circumstances give rise to an inference that is more probable than not) is acceptable to courts here (Holloway v McFeeters).

[Note each type of harm to P] Each must be considered separately to decide if there is causation.

To prove factual causation, the negligence must have been a necessary condition of the occurrence of the harm (WA s 51(1)(b)).

This requires application of the ‘but for’ test: there will be factual causation if, OBP, the P’s injury would not have occurred but for the D’s breach of DOC (Barnett v Chelsea & Kensington Hospital).

1. Evidence of what P would subjectively have done if not for D’s negligence will be considered by the court if relevant (WA s 51(3))

   1. Concerns what P (not a reasonable person) would subjectively have done.

      1. Chappel v Hart: court accepted that P would have delayed the operation and avoided harm

2. The ‘but for’ test is insufficient alone and must be applied using common sense and value judgments (March v Stramare).

3. Where the link between D’s negligence and the harm to P is limited to D’s act putting P into the spatial and temporal position where P encounters the hazard, D’s negligence is not a legal cause of the injury (Chappel v Hart, March v Stramare).

[Note prima facie result under the but for test]

However, if there are multiple sufficient causes, such that the test is not satisfied, the court may nevertheless impose responsibility for factual causation on D where appropriate (WA s 51(2)).

1. The court may decide factual causation is proven if D’s negligence materially contributes to P’s harm but cannot be shown to have been a necessary condition of its occurrence (Strong v Woolworths).

[Note if appropriate eg if two people caused a death together]

Increased risk

If it is unclear that D’s act was a necessary condition of D’s harm, but it made the harm more likely, a court may apply the doctrine of increased risk, though it is very uncertain in Australia.

Arguments for increased risk

In Amaca v Booth, the High Court found that where a cumulative effect of exposure to something is known to cause illness, and D was responsible for P’s substantial exposure to that thing, it will be deemed that D has materially contributed to P’s harm if the illness does arise; and this is enough to show factual causation.

[Note whether this applies to the circumstances and whether factual causation would be shown]

P may argue that under WA s 51(2), even where something cannot be proved to be a necessary condition of harm, the court may deem it as such. Arguably then an Australian court should apply the House of Lords case of Fairchild v Glenhaven, which held that injustice to the D is outweighed by policy reasons in favour of compensating the P.

P can argue that the similar test propounded by Kirby and Gaudron JJ in Chappel v Hart should apply. They held that if the P shows

• the D breached the DOC,

• the breach increased the risk that the P would suffer a particular kind of injury, and

• the P did in fact suffer an injury of that kind,

then a prima facie case of causation is established. This means the burden of disproving factual causation is shifted to D.

[Apply this test and decide whether D can show there is no factual causation]

Arguments against increased risk

However, D may argue increased risk does not apply in Victoria, because

1. Per WA s 52, the P must prove causation OBP, and if increased risk is allowed, the standard of proof is lowered.

   1. Kiefel J in Tabet v Gett indicated that the standard of proof could not be lowered and indicated accordingly that increased risk would not apply

2. Amaca v Ellis did not consider increased risk where it could in fact have been applied, suggesting increased risk does not apply in Australia.

D may also argue if it does apply, it is only if all causative agents operate in the same way (HOL in Barker v Corus).

I think increased risk does not apply in Australia, except perhaps in situations closely analogous to Amaca v Booth.

Conclusion: factual causation [note if made out per facts]

Under WA s 51(1)(b) and 51(4), the court must decide legal causation - that it is appropriate for D’s liability to extend to the harm caused. It will not be appropriate when harm arose by a supervening event (a novus actus interveniens or ‘NAI’) that breaks the chain of causation between D’s negligence and the harm to P: Haber v Walker, March v Stramare.

Here, D will argue there is an NAI in [per facts].

For an act to be considered an NAI, it must be ‘unreasonable, extraneous or extrinsic’ (The Oropesa) and must be:

• a human action properly regarded as voluntary (Haber v Walker)

• be a causally independent event properly regarded as connected to the wrongful act/omission only by coincidence (Haber v Walker).

Voluntariness

A human act is voluntary if the person doing the act has exercised free choice (Haber v Walker).

1. Action that is a natural consequence of the negligent act of D will not be an NAI, even where the action taken by that person was not the best course to take or was harmful (The Oropesa).

2. Acts done under substantial pressure created by the wrongful act are not considered voluntary (Haber v Walker).

Subsequent negligent acts of P or third party

1. An act of P may be an NAI (March v Stramare). However, courts prefer to consider this contributory negligence.

2. Provided P acts reasonably in seeking or accepting medical treatment for an initial injury caused by D, negligence in administration of medical treatment does not break the chain of causation unless the treatment is “inexcusably bad” or “grossly negligent” (Mahoney v Kruschich)

   1. This is because an original injury carries a risk that negligent medical treatment might be given (Mahoney)

3. A later act of...