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Late lessons from early warnings: the Precautionary Principle 1896–2000
  1. R L Maynard

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    European Environment Agency. Editorial team chaired by Poul Harromoës. Environmental Issue Report No. 22. (Pp 212; free of charge) 2001. ISBN 92 9167 323 4. Catalogue no. TH-39-01-821-EN-C.

    Paper copy available from EEA online ordering service; or can obtain from: http://reports/

    This book, which is available free of charge, is a collection of well written accounts of cases where early warnings of impending or possible disaster were ignored. The purpose is, I think, to encourage regulators to apply the Precautionary Principle and by so doing prevent further disasters. The cases considered range from overfishing and the destruction of the Californian sardine industry (see Cannery Row by John Steinbeck) and the asbestos-mesothelioma disaster to MTBE as a substitute for lead in petrol and “mad cow disease”. In each case the lack of attention paid to early signals is stressed. A few rather more controversial cases are included: hormones as growth promoters, PCBs, and benzene in gasoline as an environmental hazard. A great deal of useful, in some cases invaluable, information is provided.

    In some of the cases it is clear that greater notice should have been taken of early warnings. In others the picture is a little less clear. For example, Professor Jim Bridges, in considering the EU decision to ban growth promoters with steroid activity, points out that the decision was taken in response to public concern and against the advice of the EU’s own scientific committee and the World Health Organisation. What are we to make of this? Similarly, the evidence that exposure to ambient concentrations of benzene is damaging to health is not strong. The authors accept that their account deals only with “false negatives” and state that they failed to find good examples of “false positives”. This is a very odd statement. How could examples of “false positives” be found if the requirement is to find examples of action taken that later proved to be unnecessary? How could you tell? It is at least possible that many drugs are rejected, wrongly, or at an early stage of development as a result of worrying findings in, for example, mutagenicity screening. Whether such drugs would have caused harm is unknowable.

    The authors provide an interesting discussion of the Precautionary Principle. This principle has caused a great deal of debate and we seem little nearer to a clear definition of how it should be applied than we were some years ago. The principle is easy enough to grasp: act, if there is a risk of significant harm, before proof that harm will occur, if you don’t act, is available. In practice the problem is more difficult. Should all organophosphorus compounds be banned? There is undoubted evidence that exposure to some organophosphorus compounds at high doses produces damage to the nervous system and it is conceivable that low doses also do so—or at least in some individuals. So why wait? The answer is that insecticides are important in the maintenance of public health and the production of food. The same could be said of nitrate fertilisers. What is needed is a calculus or method that allows the strength of the evidence that exposure to environmental and well controlled occupational concentrations of toxic materials causes harm to be judged. The authors do not propose such a method. Nor do the authors address the difficult problem of cost-benefit analysis. Sometimes this can be ignored: these are the easy cases. If safer alternatives, that do not add significantly to costs exist, then the decision is straightforward. In more difficult cases such alternatives do not exist and are not likely to be developed until a ban or partial ban on the primary compound or product has been enacted. Additionally, the authors do not consider how to decide how large an adverse impact may be acceptable. How to equate costs and benefits remains a difficult issue: valuing health is repugnant to many and yet, deciding on how much to spend without some means of valuation, becomes very difficult indeed. The authors do not take us far in this area, though an analysis of the costs and benefits of using DDT to control mosquitoes might have been instructive.

    A particularly interesting section of the report deals with the alleged dislocation between policy institutions and the public. The authors are sharply critical of what they assert are common responses by policy makers—in particular the tendency to call for more data and what the authors describe as the policy maker’s attitude to what they (the policy makers) conceive as the public’s desire for certainty and zero risk. The authors deplore the attitude of some which suggests that the Precautionary Principle is “pandering to populist and anti-science sentiment”. The authors, rightly in my view, stress that policy making cannot be based on “facts” alone but should include “values”. Unfortunately, reaching a consensus on values is not at all easy and, though practices such as stakeholder involvement help, judging the public’s attitude to risk is difficult. We are all “unscientific” in our attitudes to risk—at least I find myself inconsistent about personal risks. Engaging the public in policy making is the challenge of risk management in all countries.

    In conclusion then, this is a useful book that provides much for regulatory toxicologists to ponder on. It is clear that the authors feel that regulators often get things wrong: unfortunately, we have no way of knowing how often they “get things right”.

    Supplementary materials

      Late lessons from early warnings: the Precautionary Principle 1896�2000
      RL Maynard

      Publisher's correction
      A copy of this book is available to download free-of-charge from EEA Online.
      The URL, however was published incorrectly. The correct link is:

      The error is much regretted