Precautionary Principle

views updated Jun 08 2018


The precautionary principle was introduced into environmental politics in response to a perception that existing policies did not provide adequate protection to the environment. The most prominent formulation was adopted as Principle 15 of the Rio Declaration from the 1992 United Nations Conference on Environment and Development: "In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation" (United Nations 1992). The principle has important implications to the interpretation of science and the regulation of technology, and is an expression of values in relation to the environment.


It is important to distinguish between the precautionary principle, a precautionary approach, and precautionary action. The precautionary principle is a framework for thinking that provides foresight in situations characterized by uncertainty, ignorance, and ambiguity, and where there are potentially large pros and cons for both regulatory action and inaction. As a principle, it may have legal standing with implications for applications in the international arena. In the European Union, precaution is interpreted as such a principle with legal standing, and was officially adopted as such in the Maastricht Treaty of 1992.

A precautionary approach is a way of doing things along the same lines of thought, but has no legal standing. In international trade disputes, the United States tends to interpret the precautionary principle as an approach and not a principle with legal standing. A precautionary action is simply a measure taken to implement the thought behind the principle, or it may be an isolated action taken for other or related reasons.


Histories of the precautionary principle and of precautionary actions are different. Precautionary actions are known from before the term was invented. Examples can be drawn from legislation in both the European Union and the United States. However, precaution as a principle dates back to German legislation on air pollution from 1976, where the principle was called "Vorsorgeprinzip," where the German word Vorsorge means "care" as much as "precaution" (Boehmer-Christensen 1994). The difference is subtle but significant, because "care" is a positive expression of responsibility and prudence, while "caution" has a connotation of "not daring" and "risk aversion," frequently used in a derogatory way implying that one is too cautious. The German legislation of 1976 introduced many measures related to duty ethics: BAT (Best Available Technology), ALARA (As Low As Reasonably Achievable), LCA (Life Cycle Analysis), and the concept of cleaner production. The common feature of these approaches is that one has an obligation to do the best from the perspective of reason, prudence, and environmental sustainability.

The precautionary principle was given many interpretations at various international conferences (such as the North Sea conferences in 1984 and 1987, and the Bergen Conference on Sustainable Development in 1990) building up to the Rio conference in 1992. The European Union adopted the principle at the constitutional level in the Maastricht Treaty (1992) by a simple statement in Article 174: Community policy "shall be based on the precautionary principle... ." A commission communication provided an interpretation of the precautionary principle (European Commission 2000), and at the end of the same year this interpretation was endorsed in the Nice Treaty.

In the United States, Kenneth Foster, Paolo Vecchia, and Michael Repacholi (2000) published in Science a policy commentary on the E.U. interpretation. This commentary argued that under the practical interpretations adopted by the European Union, the precautionary principle was not in conflict with the weight of evidence analysis approach more typically employed by scientists and health administrators in the United States. Retrospective historical analyses (Harremoës, Gee, MacGarvin, et al. 2002) and contemporary case studies (Tickner 2003) have tended to support this assessment. Andrea Saltelli and Silvio Funtowicz (2003) and others also have explored options for operationalizing basic intuitions involved in the precautionary principle.

Basic Interpretations

The overall impression is that the precautionary principle is a response to societies strongly influenced by positivism, which tends to regard scientific and technological development as a priori beneficial. The background is an increasing awareness of the potentially detrimental effects of scientific and technological development. Accordingly, the precautionary principle may be interpreted in several ways and is subject to intensive debate in scientific, technical, social, legal, and political terms. There are two extreme misinterpretations of the principle.

One misinterpretation considers the precautionary principle a one-sided argument for the elimination of all adverse effects on health and environment. To demand absolute proof of safety before undertaking any action is, of course, not realistic, and this view is derogatorily referred to as the risk averse interpretation. Were one to apply the precautionary principle in this sense to the precautionary principle, the principle itself would have to be rejected.

A counter-misinterpretation considers any use of the precautionary principle as an unwarranted, costly, unjustified approach to environmental protection, especially in comparison to existing approaches of risk assessment and management and the effect of tort liability law. The precautionary principle is considered a threat to the foundation of technological progress because it would halt innovation and development.

Both interpretations are typical of the polarized debate. The more common or balanced interpretation is that the precautionary principle may be applied when uncertainties are so great that it is impossible to predict the impact of technological development with any degree of accuracy, there are good grounds to suspect danger, and yet policy decisions need to be made. More specifically, in cases of significant uncertainty, when there are both sufficient scientific grounds for suspecting that a new development may have a potential for causing large scale, serious, or irreversible harms, the precautionary principle simply judges that it is more prudent to err on the side of safety. This is obviously an extension of the Hippocratic principle to avoid doing harm, to minimize risk when attempting to do good.

Of course, possible harms can always be considered from more than one perspective. Where environmentalists may see potential harms to the environment from the introduction of a new technology, economists may envision potential harms to the economy from blocking introduction of the same technology. Indeed, taking economic development as the status quo rather than the natural world, economists and business leaders can easily appeal to the precautionary principle to limit technological regulation, claiming that false alarms cause more harm than failures to identify and act on potential dangers. In the face of arguments to this effect by, for example, Bjørn Lomborg (2001) and others, it has been argued that on balance "the evidence indicates that we are receiving substantial benefits from our response to environmental alarms" (Pascala, Bulte, List et al. 2003, p. 1188).

Normative, Balance of Proof, and Risk Perspectives

Further specification of the balanced or moderate interpretation is nevertheless required and has taken at least three forms. The normative specification calls for a number of concerns to be addressed in all cases where there are reasonable possibilities of large-scale, serious, or irreversible harms. This specification has been developed in response to a tendency to disregard a number of prudent concerns. It is important, for instance, to identify and constructively account for uncertainty and ignorance, to assure interdisciplinary perspectives, to evaluate a range of options, to take full account of the values and perspectives of all stakeholders, to assure regulatory independence, and to act on reasonable grounds for concern. In the case of potentially large-scale, serious,

Type I and Type II Errors
Experimental ResultsWorldly Reality
SOURCE: Courtesy of Poul Harremoës.
 − (not harmful)+ (harmful)
+ (harmful)False positive Type I errorTrue
− (not harmful) TrueFalse negative Type II error

or irreversible harms, it is further appropriate to choose robust solutions that are adaptable to changing circumstances, because initial decisions are necessarily going to be taken under significant uncertainty, ignorance, or ambiguity (European Environmental Agency 2001).

The balance of proof specification is based on consideration of the risk of a mistaken decision. It can be assumed that no procedure for identification and documentation of environmental harmlessness is certain. There will always be some degree of uncertainty, because of the statistical uncertainties associated with practical experiments and cognitive uncertainties regarding cause-effect relationships.

The distinction between Type I and Type II errors is relevant here as indicating two possible ways in which laboratory results can differ from real-world phenomena. As they occur in a court of law, the two errors are those of convicting an innocent person (Type I) and failing to convict a guilty person (Type II). In the first instance, laboratory experiments could reject a presumption of environmental safety regarding some new technology (guilty verdict), when in fact it is safe (or innocent). This type of mistake or error is known as a false positive. In the second instance, laboratory results could fail to reject a presumption about the environmental safety of a new technology (judge the technology not guilty), when in fact it is unsafe (guilty). This is known as a false negative. See Table 1. As Kristin Shrader-Frechette has argued, the dangers of Type I errors are risks to industry (and thus economic risks to the public), whereas the danger of Type II errors pose risks to the environment (and thus health risks to the public).

Insofar as the legal system places its emphasis on avoiding Type I errors (false convictions), it is necessarily subject to Type II errors (false acquittals). In a similar manner, insofar as science is more concerned to avoid false assertions (that X causes harm when it does not) than false denials (that X is does not cause harm when it does), because it is denials that can be falsified by experiment whereas assertions can never be fully confirmed by experiment, then science may be said to have a bias toward letting guilty technologies go free. From this perspective, the precautionary principle promotes shifting the balance of proof from concern with avoiding false convictions to avoiding false acquittals. In medicine, too, physicians have traditionally been concerned first and foremost with avoiding treatments that might harm.

In the regulation of developments that may be harmful to humans or the environment, the standard with respect to choice of acceptable types and levels of error may be thus reasonably quite different from those acceptable in science or in criminal courts. Levels of proof may be graded as follows: "vague, circumstantial, substantial, beyond reasonable doubt, certain." The required level of proof must be determined in relation to the potential harm and the claimed benefits of the activity in question. Cases of potential large-scale, serious, or irreversible harms may justify setting the level of proof at a lower level than "beyond reasonable doubt." In the European Union, "reasonable grounds for concern" is suggested as level of proof for invocation of the precautionary principle with regard to the regulation of chemicals and technological activities (European Commission 2000, p. 9).

These issues are also important to the question of who shall carry the burden of proof. Should the producer, manufacturer, or importer, on the one side? The government, on another side? Or the public, by means to liability suits, on still another side? In many cases, society has adopted the principle of prior approval (positive lists) before placing on the market certain products, such as drugs, pesticides, and food additives. Accordingly, the precautionary principle incorporates a proposed reversal of the burden of proof from the public to the proponent of any development that has a potential for large-scale, serious, or irreversible harms.

This is highly controversial, because the free market economy tends to be based on the principle that any economic activities are permissible as long as they are legal and subject to tort liability for the recuperation of damages. Opponents to the precautionary principle consider any restriction of this economic liberty as detrimental to technical and economic development. In the case of development of new chemicals and genetically modified organisms (GMOs), industry tends to consider such developments potentially so beneficial to society that industry should not have to bear the costs of a greater burden of proof; instead, liability should be invested in society as a whole.

The risk specification involves a comprehensive risk assessment in accord with the standards established in this field. The normative and balance of proof specifications may be included in the process. But a technical risk assessment is assumed to be more scientific and objective, involving as it does hazard identification, dose-response assessment, exposure assessment, and risk characterization (Environmental Protection Agency 1997, Lewalle 1999).

Social studies of science have, however, provided grounds for questioning the complete objectivity of such procedures, which are always undertaken by human beings with their own interests and perspectives. This is why the normative approach explicitly insists that a wide range of stakeholder values and perspectives be considered from the beginning even in framing the issue.

Subsequent risk management involves risk evaluation, emission and exposure control, and risk monitoring, plus risk communication. Risk evaluation and the regulation of emissions and exposures is where political and ethical choices come most obviously into play. What are the values and perspectives to be considered, and what is an acceptable risk? The European Commission communication on the precautionary principle, for instance, explicitly states that "the protection of public health should undoubtedly be given greater weight than economic considerations" (2000, p. 19).

Supplementary Principles

Invoking the precautionary principle nevertheless requires other principles to be considered. The European Commission has named five of these.

  • Proportionality. Any decision is required to be proportional—that is, even a preliminary invocation of the precautionary principle must consider the balance between the pros and cons of a precautionary action, accounting for all aspects known at the time. In proportionality all concerns may count, not only consequences, but also deontological concerns, like duties, rights, and considerations of justice.
  • Non-discrimination. Invocation of the precautionary principle means that comparable situations should not be treated differently, unless there are objective grounds for doing so.
  • Consistency. Measures should be similar to previously adopted measures in similar circumstances.
  • Pros and cons of action versus lack of action. Even in a provisional invocation of the precautionary principle, an analysis should be made of the factors pointing in favor versus against action or no-action.
  • Scientific development. It is an essential part of the invocation of the precautionary principle to initiate research and monitoring in order to reduce the uncertainty and ignorance that cause the invocation.

Precautionary Principle Implementation

The means by which the precautionary principle should be implemented also have been the focus of much debate. Implementation must be related to other significant developments associated with risk assessment and management, and principles of good governance.

Thetendencyistoemploy participatory, discursive, and adaptable procedures. The participatory processes require the participation at an early stage of all relevant stakeholders, as well as an ongoing discourse with stakeholders for the duration of the project. Adaptive procedures are the logical consequence of the fact that uncertainty and ignorance prevail in the decision making. Accordingly, it has to be publicly admitted that any decision could be false and susceptible to change in the light of new information obtained from research and monitoring.

Concrete regulatory actions can take many forms, from initiation of research and monitoring in order to decrease uncertainty and ignorance, to outright ban of the activity in question. Consider, for example, the case of endocrine disrupters.

Endocrine disrupters are natural hormones, which may be discharged in large quantities (such as the female hormone, estrogen, large amounts of which are discharged in wastewater, in large part due to increased excretion of residues from use of contraceptive pills), or hormone-like, artificial substances with a similar effect (such as Tributyltin [TBT], which is used in antirust paint on boats).

It has been demonstrated that increased concentrations of endocrine disrupters may cause sexual disturbances called imposexin fish and invertebrates in the aquatic environment (European Environment Agency 2001, p. 135–143). The first reaction was to increase research, because the evidence was insufficient to justify regulatory actions. With increasing evidence of serious effects, however, TBT has been banned for use on pleasure boats. Measures aimed at paints on commercial ships are forthcoming.

In the case of release of estrogen with wastewater, the question is whether scientifically-based suspicions of serious harms are sufficient to invoke the precautionary principle and demand either a ban of contraceptive pills or, more likely, to demand that wastewater treatment include the removal of endocrine disrupters before water is discharged into the environment. The key question is whether to invoke the precautionary principle immediately or wait for the results of a larger and more reliable risk assessment, which may be time consuming due to a need for more research.

Legal Status

Ambiguities remain regarding interpretation, application, and implementation. Ultimately such ambiguities will be reduced by case law precedence built up through court decisions. Several judgments already point in this direction.

Internationally, the Agreement on Sanitary and Photosanitary Measures and the Agreement on Technical Barriers to Trade have been brought before the World Trade Organization (1997). In Europe, an influential case is that of antimicrobial growth promoters brought before the European Court of Justice (1999).

A European Commission ban on certain antibiotics as growth promoters in animal production was upheld by the court with reference to the precautionary principle because of scientifically-based indications that widespread use of antibiotics might adversely affect the bacterial resistance to related antibiotics for humans (European Environment Agency 2001). However, the judgment also outlines the severe limitations and formal requirements associated with invoking the precautionary principle.


The precautionary principle is not a scientific principle. It is an ethical principle in the sense that it makes a statement regarding values and the proper procedures for governance and due process. It is prudent to take action in spite of lack of complete scientific evidence when there are significant uncertainties, recognized ignorance, and ambiguity, combined with scientifically-based suspicions of large scale, serious, or irreversible harms. This is a deontological principle in the sense that it prescribes an approach to prudent action in response to the awareness of the situation.

However, for the precautionary principle to be invoked there must first have been a preliminary risk assessment combined with a preliminary cost-benefit or cost-effectiveness assessment. In ethical terms, what must happen first is a preliminary utilitarian appraisal, the uncertainty of which may provide the justification for invoking the precautionary principle at the time of decision making. The challenge is to "avoid paralysis by analysis" (European Environmental Agency 2001, p. 181).


SEE ALSO Science Policy;Uncertainty.


Boehmer-Christensen, S. (1994). "The Precautionary Principle in Germany: Enabling Government." In Interpreting the Precautionary Principle, ed. Tim O'Riordan and James Cameron. London: Earthscan.

Cranor, C. F. (1999). "Asymmetric Information, The Precautionary Principle, and Burdens of Proof." In Protecting Public Health and the Environment, Implementing the Precautionary Principle, ed. Carolyn Raffensberger and Joel Tickner. Washington, DC: Island Press.

European Court of Justice. (1999). Pfizer v. EC (T 13/99) and Alpharma v. EC (T 70/99).

Foster, Kenneth R.; Paolo Vecchia; and Michael H. Repacholi. (2000). "Science and the Precautionary Principle," Science 288(5468): 979, 981.

Harremoës, Poul; David Gee; Malcom MacGarvin; et al. (2002). The Precautionary Principle in the 20th Century: Late Lessons from Early Warnings. London: Earthscan.

Harremoës, Poul. (2003). "Ethical Aspects of Scientific Incertitude in Environmental Analysis and Decision Making." Journal of Cleaner Production 11: 705–712.

Lomborg, Bjørn. (2001). The Skeptical Environmentalist: Measuring the Real State of the World. Cambridge, UK: Cambridge University Press.

Lewalle P. (1999). "Risk Assessment Terminology: Methodological Considerations and Provisional Results." Terminology Standardization and Harmonization II(1–4): 1–28.

Pascala, S.W.; E. Bulte; J.A. List; and S.A. Levin. (2003). "False Alarm over Environmental False Alarms." Science 301: 1187–1188.

Popper, Karl R. (2000). Conjectures and Refutations: The Growth of Scientific Knowledge, 5th rev. edition. London: Routledge and Kegan Paul.

Saltelli, Andrea, and Silvio Funtowicz. (2003). "The Precautionary Principle: Implications for Risk Management Strategies." European Journal of Oncology 2: 67–80.

Shrader-Frechette, Kristin S. (1991). Risk and Rationality: Philosophical Foundations for Populist Reforms. Berkeley: University of California Press.

Tickner, Joel A., ed. (2003). Precaution, Environmental Science, and Preventive Public Policy. Washington, DC: Island Press. A collection of 24 analyses, many of them contemporary case studies.


Environmental Protection Agency. (1997). "Risk Assessment and Risk Management in Regulatory Decision-Making." The Presidential/Congressional Commission on Risk Assessment and Risk Management, Final Report Volume 2, Glossary. Available from

European Commission. (2000). "Communication from the Commission on the Precautionary Principle." Available from

European Environment Agency. (2001). "Late Lessons from Early Warnings: The Precautionary Principle 1986–2000." Environmental Issues Series 22. Available from

European Union. (1992). Treaty of the European Union (The Maastricht Treaty). Available from

United Nations. (1992). "Rio Declaration on Environment and Development, United Nations, A/CONF.151/26, vol. I." Available from

World Trade Organization. (1997). "Agreement on the Application of Sanitary and Phytosanitary Measures." Available from

Precautionary Principle

views updated May 21 2018


The Precautionary Principle is referred to in the 1992 Rio Declaration on Environment and Development; the declaration includes the principle, "Nations shall use the precautionary approach to protect the environment. Where there are threats of serious or irreversible damage, scientific uncertainty shall not be used to postpone cost-effective measures to prevent environmental degradation." This idea is being increasingly invoked as a rationale for environmental health policy, including its formal appearance in international treaties. The Precautionary Principle, along with terms such as "sustainable development," expresses a broad approach for which there is general support and agreement. However, as with sustainable development, it is a term that is often difficult to crisply define, and its implications to specific issues are not easily agreed upon.

Three elements appear to be central to the Precautionary Principle. First, there must be some factual basis that raises a legitimate reason for concern; second, there is no certainty as to whether the concern will turn out to be justifiedor whether the proposed remedy will be effective; and third, the remedy has a reasonably substantial economic or societal cost. There is some debate as to whether the Precautionary Principle is an alternative to risk assessment or whether the two approaches are mutually complementary. In retrospect, there have been many past governmental actions that clearly rank as precautionary, without the term "Precautionary Principle" being invoked. Examples include the use of maximal available control technology for hazardous air pollutants, or ALARA (as low as reasonably achievable) for radiation protection.

Bernard D. Goldstein

(see also: Environmental Determinants of Health; Environmental Justice; Environmental Movement; Environmental Protection Agency; Risk Assessment, Risk Management )


Goldstein, B. D. (1999). "The Precautionary Principle and Scientific Research Are Not Antithetical." Environmental Health Perspectives 107:594595.

O'Riordan, T., and Cameron, J., eds. (1994). Interpreting the Precautionary Principle. London: Earthscan Publications.

Precautionary Principle

views updated May 23 2018

Precautionary Principle

The precautionary principle, also referred to as the precautionary approach, justifies the use of cost-effective measures to prevent environmental degradation even in the absence of full scientific certainty. This principle has obvious applications to various forms of environmental pollution. The principle can be traced to German national law in 1976, which states, "[e]nvironmental policy is not fully accomplished by warding off imminent hazards and the elimination of damage which has occurred. Precautionary environmental policy requires furthermore that natural resources are protected and demands on them are made with care."

The principle's first applications beyond national boundaries came in 1987. It was quickly adopted into numerous multilateral treaties and international declarations, including the 1987 Montréal Protocol on Substances that Deplete the Ozone Layer, the 1990 Bergen Declaration on Sustainable Development, the 1992 Convention on Biological Diversity, and the 1999 Treaty of Amsterdam, which has broadened and redefined the goals and institutions of the European Union.

The principle's scope varies dramatically in these documents as well as in national legislation that contains it. In some, it is limited to toxic substances that are persistent and can bioaccumulate . In others, like the Bergen Declaration, it covers all government policies with the potential to degrade the environment, even when some causal relationships have not been fully established scientifically. Some critics contend that the Principle restricts technology. It has been a focus of U.S.European Union (EU) trade disputes, as Europeans have argued for its application to genetically modified foods, animal-growth-promoting hormones , and phthalates (softeners) in polyvinyl chloride (PVC) children's toys. The U.S. government also contends that the principle is a nontariff barrier, that is a policy that interferes with exports or imports other than a simple tariff such as quota.

see also Laws and Regulations, International; Laws and Regulations, United States; Treaties and Conferences.


goklany, indur m. (2001). precautionary principle: a critical appraisal of environmental risk analysis. washington, d.c.: cato institute.

Michael G. Schechter

precautionary principle

views updated May 29 2018

pre·cau·tion·ar·y prin·ci·ple • n. the principle that the introduction of a new product or process whose ultimate effects are disputed or unknown should be resisted. It has mainly been used to prohibit the importation of genetically modified organisms and food.