Application of risk management measures; 'low risk' to 'very low risk' assessment; Wednesbury unreasonableness
59 His Honour regarded as crucial to the Panel's reasoning the passage quoted at [47] above. While the Solicitor-General was somewhat apologetic about this passage and prayed in aid the latitude given by courts to loose language by administrative decision-makers, we think that, in context, the meaning is clear enough. The Panel's approach has been to treat PCV2 as a proxy for the as yet unidentified PMWS co-factor. Since PCV2 has a number of adverse characteristics, the Panel assumed the co-factor to be as bad as PCV2 in respect of those characteristics. Therefore measures which might eliminate or reduce the presence of PCV2 would have a similar effect on the co-factor.
60 The decision-making function under consideration required:
· assessment of whether PMWS might be
- introduced
- established and
- spread
in Australia
· if so, what was the probable extent of the harm which might be caused
· what conditions might be adopted having as their object the
- prevention or
- control
of such introduction, establishment or spread and
· whether the resultant risk was "acceptably low"
61 The legislation does not suggest that quarantine decisions are to be made on an assumption that every scientific fact is known about every conceivable disease or pest that might be introduced into Australia, or that such decisions are to be delayed until all such facts are discovered and accepted. On the contrary, quarantine decisions have to be made in the existing state of knowledge. Imponderables have to be weighed and value judgements made. No specific criteria are laid down, other than the condition to be established must limit the level of quarantine risk to one which is "acceptably low" - which necessarily assumes there will be some risk.
62 In this setting, we think his Honour erred in applying, in effect, to each step in the pathway taken by the Panel a legal requirement for hard scientific data.
63 The Panel dealt with a number of other diseases in addition to PMWS. It adopted a complex and transparent decision-making process, the basic structure of which was not challenged (although there was an attack on some features such as the width of probability bands and the particular percentiles adopted). The Panel's good faith and expertise are not in issue. If in some steps, or sub-steps, of the process in relation to PMWS the Panel used estimate, or analogy, or indeed speculation, the Panel might be guilty of unscientific procedures. However APL had to show that the ultimate decision was not just unreasonable, but so unreasonable that no other similarly qualified decision-maker would have made it. That test necessarily allows for some degree of unreasonableness. Even if error in reasoning is disclosed, a conclusion of Wednesbury unreasonableness requires a major step further. In Minister for Immigration and Multicultural Affairs v Eshetu (1999) 197 CLR 611 at [40] Gleeson CJ and McHugh J said:
'… Someone who disagrees strongly with someone else's process of reasoning on an issue of fact may express such disagreement by describing the reasoning as "illogical" or "unreasonable", or even "so unreasonable that no reasonable person could adopt it". If these are merely emphatic ways of saying that the reasoning is wrong, then they may have no particular legal consequence.
41 In Puhlhofer v Hillingdon London Borough Council [1986] AC 484 at 518 Lord Brightman said:
"Where the existence or non-existence of a fact is left to the judgment and discretion of a public body and that fact involves a broad spectrum ranging from the obvious to the debatable to the just conceivable, it is the duty of the court to leave the decision of that fact to the public body to whom Parliament has entrusted the decision-making power save in a case where it is obvious that the public body consciously or unconsciously, are acting perversely." '
Later their Honours (at [43]) repeated the warning of Mason CJ in Chan v Minister for Immigration and Ethnic Affairs (1989) 169 CLR 379 at 391 against courts 'trespass(ing) into the forbidden field of review on the merits'.
64 Immediately before the passage in Eshetu quoted above, Gleeson CJ and McHugh J advert to a factual question in the case, namely the rejection by the Refugee Review Tribunal of evidence by an asylum-seeker concerning a student protest and subsequent arrests and ill-treatment of the protesters by authorities in Ethiopia. The Tribunal rejected his account because there was no mention of these events by human rights organisations or media at the time. Hill J at first instance had found this conclusion so unreasonable that no reasonable tribunal could reach it (although his Honour accepted that the Migration Act 1958 (Cth) prevented review on that ground). In the Full Court, Davies and Burchett JJ agreed with Hill J on this point but Whitlam J said that a finding to the contrary of that arrived at by the Tribunal would be 'bordering on the perverse'. In that context, Gleeson CJ and McHugh JJ said:
'Whitlam J was of the view that the reasoning displayed no error. Even if it did, however, there is a serious question whether the suggested error is of the kind to which the Wednesbury principle is directed. We are not here concerned, for example, with the unreasonable exercise of a discretion, and it is difficult to characterise the Tribunal's decision, even on Hill J's view of it, as an abuse of power.'
65 It seems therefore that it is inherently more difficult to impugn a decision on the ground of Wednesbury unreasonableness when the decision involves fact finding rather than the exercise of a discretion. Such a view would be consistent with the statement by Lord Brightman in Puhlhofer. It also accords with what was said as to the discoverability of specific error by Dixon, Evatt and McTiernan JJ in House v The King (1936) 55 CLR 499 at 505. After stating that discretionary decisions may be set aside if the primary judge (this was an appeal from a judicial decision but modern administrative law would apply the same principles to administrative decisions) acts upon a wrong principle, takes into account irrelevant matters, mistakes the facts or does not take into account some material consideration, their Honours continued:
"It may not appear how the primary judge has reached the result embodied in his order, but, if upon the facts it is unreasonable or plainly unjust, the appellate court may infer that in some way there has been a failure properly to exercise the discretion which the law reposes in the court of first instance."
66 In the present case, the Panel was not only concerned with fact rather than discretion, it had to make an assessment of future risk and measure that risk against the imponderable standard of acceptable lowness. An element of speculation, in the sense of assessing the likelihood of future occurrences, was necessarily involved: cf Minister for Immigration and Ethnic Affairs v Wu Shan Liang (1996) 185 CLR 259 at 277-278.
67 In essence, the Panel reasoned that the combination of modified dressing (removal of bones and peripheral lymph nodes) and cooking or curing would both reduce the likelihood of imported meat containing the virus and would lessen the likelihood that any given waste unit would contain enough of the virus to initiate infection. There was the further significant factor that by deboning and cooking or curing before import there would be less waste discarded in Australia.
68 His Honour accepted (at [274]) that this reasoning (reduction in volume of imported material likely to carry the virus = less risk of infection) was common sense. We agree. It can hardly be considered unreasonable. The problem for his Honour was the lack of quantification. But the question was not whether, in his Honour's words (at [279]), what measures were necessary 'to ensure PCV2 [as surrogate] infection will not survive importation'. The Panel took an unarguably reasonable, if unquantified, factual conclusion and applied it to a qualitative, verbal standard. One can legitimately argue that this was not an ideal process as a matter of scientific method. Perhaps, as was suggested in argument, some experiments might have been conducted. But the approach of the Panel cannot be characterised as one so unreasonable that no reasonable decision-maker could take it.
69 At a more detailed level, the reasoning of the Panel appears to have been based on scientific knowledge clearly articulated. For example it noted that lymphoid tissues are the primary target for PCV2 and for many other viruses. Thus removal of lymphoid tissue would reduce the risk of PCV2 (and hence its proxy), but not completely. So that particular element of risk was reduced from 'moderate' to 'low'. Similarly the Panel assumed some level of the virus in the muscle (flesh) itself.
70 We would uphold the appeal on this issue.