The Precautionary Principle: Amorphous Concept Proves Difficult to Define

Date: Sep 01, 2002

Precaution, n., 1. Previous caution or care; caution previously employed to prevent mischief or secure good; as, his life was saved by precaution. 2. A measure taken beforehand to ward off evil or secure good or success; a precautionary act; as, to take precautions against accident.

-- Webster's Revised Unabridged Dictionary (c)1996, 1998 MICRA, Inc.

Behind this seemingly innocuous two-part dictionary definition lies one of the thorniest issues at the crossroads of international trade and the protection of human health and the environment. The "Precautionary Principle," which originated in Europe, has become one of the most highly controversial sources of dispute in international circles.

Supporters of the principle view it as a necessary tool of risk management, while critics see in this amorphous concept a threat to science-based risk analysis and a thinly veiled attempt at legitimizing trade barriers under the cover of public policy. Indeed, over the past 10 years, the European Union has increasingly used the Precautionary Principle to support a variety of bans -- ranging from hormones in beef and milk, to aflatoxins in ground nuts, to genetically engineered crops -- leading to accusations of protectionism from the United States and other trade blocs.

Central to the debate is the definition of the Precautionary Principle itself -- or rather the lack thereof -- and the multitude of formulations that have appeared within the last 15 years.

Origins of the Principle

The Precautionary Principle began to emerge as an explicit and coherent concept within environmental science in the 1970s, when German scientists and policy-makers sought an understanding of "forest death" (Waldsterben) and its possible causes, including air pollution. The concept of Vorsorge ("foresight") emerged as a general rule of public policy action in situations of potentially serious or irreversible threats to health or the environment. They concluded that, in such circumstances, there is a need to act to reduce potential hazards before there is a strong proof of harm, and a need to weigh the likely costs and benefits of action and inaction.

This concept was incorporated into German law, as the Vorsorgeprinzip ("foresight principle") in the German Clean Air Act of 1974, and was invoked to justify the implementation of vigorous policies to tackle acid rain, global warming, and North Sea pollution. The principle in the German law included elements such as considerations for alternative means of "clean production," proportionality of the measure to the hazards it seeks to prevent, cost-benefit analysis, and threats of serious or irreversible harm to the environment as a prerequisite for a measure to be taken in a context of scientific uncertainty.

The Precautionary Principle has since become a cornerstone of European Community policy. Beyond Europe, it has flourished in international statements of policy, conventions dealing with high-stakes environmental concerns in which the science is uncertain, and national strategies for sustainable development.

Risk Assessment and the Precautionary Principle

Precaution, in its dictionary sense, has been applied in medicine and public health for decades -- if not centuries -- together with the advances of science. It embodies the age-old, common sense "better safe than sorry" concept. So why would the exercise of precaution be so controversial? The devil is in the details.

Webster's definitions illustrate the conflict of philosophies between the United States and the European Union over the proper use of precaution: is it the previous care or caution taken beforehand, i.e., an "awareness" of risks and attention to prevent such risks, or, as the second sense of the definition suggests, should measures be taken beforehand, as precautionary acts to ward off possible dangers in a more proactive way? To put it differently, do we rely on science-based risk assessment or the Precautionary Principle in exercising precaution?

To protect the public and the environment, modern health and environmental policies rely on risk analysis and its three components: risk assessment (how risks are identified), risk management (how risks are prevented or diminished to an acceptable level), and risk communication (how the policy is conveyed to the public). If risk management and risk communication are inherently political, risk assessment is based on the ability of science to model and predict harm.

Risk assessment was originally developed to solve mechanical problems, such as bridge construction, in which the technical process and parameters are well defined and can be analyzed. It is not an exact science, and the scientific evaluation of risks entails taking into account some unknown factors, variables, and uncertainties. During the 1970s, risk assessment techniques were increasingly used in conjunction with cost-benefit analyses to bridge the gap between uncertain science and the political need for decision-making to limit harm in extremely complex ecological and human systems.

In Europe, a series of recent health scares has contributed to the idea that somehow traditional risk analysis methods and environmental policies have failed to adequately protect human health. Institutions, governments, politicians, and scientists in Europe were eager to regain the public trust lost after outbreaks of bovine spongiform encephalopathy (better known as "mad cow disease") in the United Kingdom and elsewhere, dioxins in Belgium, and HIV-contaminated blood transfusions in France.

The Precautionary Principle became a tool of risk management, distinct from risk assessment, to be used in situations where science proved incapable of providing clear answers. In its Feb. 2, 2000, Communication, the European Commission distinguished a "prudential approach" from the Precautionary Principle:

Prudential approach is part of the risk assessment policy which is determined before any risk assessment takes place; it is therefore an integral part of the scientific opinion delivered by risk evaluators.

On the other hand, application of the Precautionary Principle is part of risk management, when scientific uncertainty precludes a full assessment of the risk and when decision- makers consider that the chosen level of environmental protection or of human, animal and plant health may be in jeopardy.

In other words, in the EU view, the two prongs of "precaution" -- the awareness of a risk, and the proactive measure -- are superposed when there is scientific uncertainty.

Opponents of the Precautionary Principle consider the principle to be anti-scientific, an approach that replaces risk assessment altogether with purely political considerations. Risk assessment already incorporates variables and conservatism. The additional caution exercised when applying the Precautionary Principle, in the absence of any scientific rationale, is redundant at best, and can serve to justify trade barriers under the cover of public policy.

Despite U.S. opposition to the adoption of the Precautionary Principle in international agreements as it is interpreted and applied in the European Union, the United States has nonetheless promoted and applied "precautionary prevention" numerous times throughout its history. Among the many examples of "precautionary legislation" are the enactment of the Federal Food, Drug, and Cosmetic Act of 1938, which established a system of pre-market approval for new drugs, and the subsequent Food Additive Amendment of 1958 and Color Additive Amendment of 1960, which required manufactures of food additives and color additives, respectively, to establish the safety of their products.

More recent examples of proactive precautionary measures include the ban on the use of scrapie- infected sheep and goat meat in the animal and human food chain in the early 1970s (which may have helped the United States to avoid BSE), a ban on the use of chlorofluorocarbons in aerosols in 1977 (several years before similar action was taken in most of Europe), and a ban on the use of the hormone diethylstilbestrol (DES) as a growth promoter in beef from 1972-79, nearly 10 years before the EU ban in 1987.

If, originally, the Precautionary Principle was not adverse to a scientific approach to risk, it has increasingly evolved from an acceptable, if not necessary, risk management approach, to become a tool for the advancement of the views of the more radical environment and health advocates. Despite recent guidelines released by the European Commission, implementation of the Precautionary Principle remains questionable, particularly in the midst of varying formulations of the principle in a multitude of international agreements.

Interpretation of the European Commission

The Precautionary Principle is now enshrined within the legal framework of the European Union. Article 174 of the Treaty Establishing the European Community provides that the Community policy on the environment shall be based on the Precautionary Principle.1/ However, the principle is not defined in the EC Treaty, and EU case law on the use of the principle remains very limited.

In this context, on Feb. 2, 2000, the European Commission, acknowledging the confusion stemming from the multitude of interpretations and sometimes contradictory views, released a Communication outlining its approach to the principle, and providing guidelines for its implementation. Although the Treaty only refers to the protection of the environment, per se, the Commission makes clear that the Precautionary Principle extends to protection of human, animal and plant health.

In order to improve a basic understanding of the principle and avoid any abuse of the principle as a disguised form of protectionism, the Commission established five general principles of application of the Precautionary Principle that must be met by precautionary measures:

  1. Proportionality: the measures should be proportional to the desired level of protection, and must not aim at zero risk.

  2. Non-discrimination: the measures should not be discriminatory in their application. Comparable situations should not be treated differently and different situations should not be treated in the same way, unless there are objective grounds for doing so.

  3. Consistency: the measures should be consistent with the measures already adopted in similar circumstances or using similar approaches. The measures should be comparable in nature and scope with measures already taken in equivalent areas in which all the scientific data are available.

  4. Examination of the benefits and costs of action and lack of action: the measures must be based on an economic cost/benefit analysis. Other analysis methods, such as the socio-economic impact, may also be relevant.

  5. Examination of scientific developments: the measures must be of a provisional nature pending the availability of more reliable scientific data; scientific research shall be continued with a view to obtaining more complete data.

The Precautionary Principle was recently confirmed as a cornerstone of European policy in the Regulation of Jan. 28, 2002, which spelled out the basic principles of European food law and established a European Food Safety Authority. Article 7 of the Regulation incorporates the Precautionary Principle as a regulatory tool for the protection of health in the Community, as well as the general principles of application established by the Communication of February 2000.2/

At the heart of the controversy over the implementation of the Precautionary Principle is the leeway that is granted authorities to consider factors beyond the ones used in traditional risk management methods, as highlighted in Article 7, paragraph 2:

Measures adopted . . . shall be proportionate and no more restrictive of trade than is required . . . regard being had to technical and economic feasibility and other factors regarded as legitimate in the matter under consideration.

(Emphasis added.)

As written, Article 7 allows for very subjective and irrational factors such as consideration of consumer perception and public opinion to balance practical considerations as crucial as technical and economic feasibility of the measure.

The Precautionary Principle and International Trade

The conflict of philosophies between the United States and the European Union, and the various trade blocs aligned with their respective positions, crystallizes in international trade circles. The Preamble to the World Trade Organization agreement cites protection of environment as one of its objectives.

The European Union is pushing for the Precautionary Principle to be taken into account in various WTO agreements, notably in the Agreement on Sanitary and Phytosanitary Measures (SPS) and in the Agreement on Technical Barriers to Trade (TBT), to ensure that the general principle is recognized and duly enforced -- and that the European Union is not found in violation of such agreements when applying the principle. While the term "Precautionary Principle" is not explicitly used in the WTO agreements, the European Union has generally interpreted the agreements in light of the Precautionary Principle.

For instance, the European Union construes Article 5.7 of the SPS Agreement as sanctioning the principle. That article allows members to adopt provisional "measures on the basis of available scientific information" while they "seek to obtain additional information necessary for a more objective assessment of risk and review the sanitary or phytosanitary measure accordingly within a reasonable period of time."

Under the EU interpretation, the SPS Agreement would allow members to take measures restrictive of trade based on the Precautionary Principle, i.e., without establishing the existence of the risk scientifically and potentially based in part on very subjective considerations, provided that the measures are reviewed with the advances of science -- the "reasonable period of time" can then mean several years.3/

The Precautionary Principle Beyond Europe

Under the influence of the European Union, the concept of a Precautionary Principle has progressively been accepted as a tool of risk management beyond European borders.

While never expressly mentioning the adoption of the "Precautionary Principle," no fewer than 14 multilateral agreements as of March 2002 refer to the concept more or less directly. Unfortunately, improved visibility has not brought improved clarity.

Indeed, a Swedish author, Per Sandin, identifies no fewer than 19 different formulations of the principle, often individually vague and mutually contradictory.4/ The various formulations of the principle can be categorized into three different types of interpretations:5/

  1. Uncertainty does not justify inaction. In its most basic form, the Precautionary Principle permits regulation in the absence of complete evidence about the particular risk scenario. The most commonly used reference to the principle, found in the Rio Declaration of 1992, falls into this category. Article 15 of the declaration indicates that lack of full scientific certainty cannot justify postponement of cost-effective measures to protect the environment where there are threats of serious or irreversible damage.6/ This version of the Precautionary Principle was also adopted at the Convention on Climate Change of May 1992,7/ in the Bergen Declaration on Sustainable Development,8/ and more recently at the 2000 Conference of the parties to the Convention on Biological Diversity (Cartagena Protocol on Biosafety).9/

  2. Uncertainty justifies action. This version of the precautionary approach is more aggressive. Formulations of the principle suggesting that actions be taken to protect the environment from dangerous substances, even in the absence of scientific evidence establishing a causal link between emissions and effects, can be found in the Second North Sea Declaration and Third North Sea Conference.10/

  3. Uncertainty requires shifting the burden and standard of proof. This version of the Precautionary Principle is the most aggressive. It holds that uncertain risk requires forbidding the potentially risky activity until the proponent of the activity demonstrates that it poses no (or acceptable) risk. One such formulation was stated in January 1998 at Wingspread, headquarters of the Johnson Foundation, at a meeting of lawyers, scientists, policy makers and environmentalists. Under the Wingspread formulation, the proponent of an activity must establish the safety of the activity, and precautionary measures should be taken regarding any activity raising threats of harm to the environment or human health, even if some cause-and-effect relationships are not fully established scientifically.11/ Even more radical, an early reference to the Precautionary Principle appears in the World Charter for Nature (1982), which states: "where potential adverse effects are not fully understood, the activities should not proceed."12/

There is an increasing trend in the European Union and beyond for a gradual shift from the first to the third type of formulation.


The European Union has made it clear that the Precautionary Principle has become "a central plank of Community policy" and that the principle will be supported by its institutions and used as a basis for EU positions on the protection of health and the environment at the international level. The Precautionary Principle may very well become a principle of international law, even though it is, more than ever, a highly contested doctrine.

The principle was not originally designed as an alternative to risk assessment, a tool to supersede scientific risk analysis and science-based policies. Nonetheless, as is reflected in the February 2000 Communication of the Commission and the 2002 Food law Regulation, it opens the door to the consideration of very subjective factors as a basis for measures that can have severe impacts on international trade and scientific developments.

The potential for abuse of the principle is considerable, and there is a need for clear safeguards. The principle is gaining an impetus based on a perception that science is not infallible and that somehow the environmental policies in place have failed to protect us. In western nations, life expectancy increases every year, and scientific advancements help us live longer, healthier lives. Yet, ironically, as science evolves and we improve our understanding of the mechanics of biology, chemistry, and our dependence on the environment, more alarms are being sounded -- as if our awareness of a potential risk made the threat more immediate.

Thus, the principle must remain an auxiliary policy supplementing traditional science-based risk assessment. The principle focuses on the risks, the costs of action or lack of action to prevent such risk, and the perception of the public. Yet risk management must also take into account the costs of foregoing new products, in order to avoid an institutional bias against the development of new technologies and a reactionary approach to scientific progress.

For years now, the European Union has imposed a moratorium on the commercialization of new genetically engineered crops despite a lack of data indicating any adverse effect on human health, costing billions of dollars to the European and American biotech industry alike. In Sweden -- one of the EU Member States at the forefront of extending the scope of the Precautionary Principle -- some chemical industries are abandoning the Swedish market completely as they see the regulatory system being excessively costly with little benefit.

A principle of precaution in any policy is legitimate, and should be integrated into all risk management. However, difficulties arise when such a concept is made into law; after all, how can we hope to legislate common sense? In order to avoid forestalling scientific progress and maintain fair trade, we can only hope that the principle will be used with precaution.


1Consolidated Version of the Treaty Establishing the European Community, OJ C 340, 10.11.1997, p.173.

Article 174 reads in part:

  1. Community policy on the environment shall aim at a high level of protection taking into account the diversity of situations in the various regions of the Community. It shall be based on the Precautionary Principle and on the principles that preventive action should be taken, that environmental damage should as a priority be rectified at source and that the polluter should pay. . . .

  2. In preparing its policy on the environment, the Community shall take account of:

  • available scientific data, . . .

  • the potential benefits and costs of action or lack of action. . . .
2Regulation (EC) No. 178/2002 of the European Parliament and of the Council of Jan. 28, 2002, laying down the general principles and requirements of food law, establishing the European Food Safety Authority and laying down procedures in matters of food safety." OJ L 031, 01.02.2002, p.1.

Article 7 of the Regulation (titled, "Precautionary Principle") provides:

  1. In specific circumstances where, following an assessment of available information, the possibility of harmful effects on health is identified but scientific uncertainty persists, provisional risk management measures necessary to ensure the high level of health protection chosen in the Community may be adopted, pending further scientific information for a more comprehensive risk assessment.

  2. Measures adopted on the basis of paragraph 1 shall be proportionate and no more restrictive of trade than is required to achieve the high level of health protection chosen in the Community, regard being had to technical and economic feasibility and other factors regarded as legitimate in the matter under consideration. The measures shall be reviewed within a reasonable period of time, depending on the nature of the risk to life or health identified and the type of scientific information needed to clarify the scientific uncertainty and to conduct a more comprehensive risk assessment.

3In this regard, the Appellate Body on Japan - Measures affecting agricultural products (AB- 1998-8, paragraph 89) provides four cumulative requirements that must be met in order for a Member State to adopt and maintain provisional SPS measures in compliance with Art. 5.7.

  1. the measure is imposed in respect of a situation where "relevant scientific information is insufficient"

  2. the measure is adopted "on the basis of available pertinent information"

  3. the Member State must seek to obtain the additional information necessary for a more objective risk assessment, and

  4. The Member State must review the measure accordingly within a reasonable period of time. ("Reasonable time" is determined on a case-by case basis, see id., paragraph 93).
4P. Sandin, "Dimensions of the Precautionary Principle," Human and Ecological Risk Assessment, Vol. 5 (1999), n. 5, p. 889. 5J.B. Wiener and M.D. Rogers, "Comparing precaution in the United States and Europe," forthcoming in Journal of Risk Research, pp. 4-5. 6"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." Rio Declaration on Environment and Development, June 14, 1992, 31 ILM 874. 7"The parties should take precautionary measures to anticipate, prevent, or minimize the causes of climate change and mitigate its adverse effects. Where there are threats of serious or irreversible damage, lack of full scientific certainty should not be used as a reason for postponing such measures, taking into account that policies and measures to deal with climate change should be cost-effective so as to ensure global benefits at the lowest possible cost." Framework Convention on Climate Change, May 9, 1992, 31 ILM 849. 8"In order to achieve sustainable development, policies must be based on the Precautionary Principle. Environmental measures must anticipate, prevent, and attack the causes of environmental degradation. Where there are threats of serious or irreversible damage, lack of full scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation." Bergen Ministerial Declaration on Sustainable Development in the ECE Region. UN Doc. A/CONF.151/PC/10 (1990), 1 YB Int'l Envtl Law 429, 4312 (1990). 9"Lack of scientific certainty due to insufficient relevant scientific information and knowledge regarding the extent of the potential adverse effects of a living modified organism on the conservation and sustainable use of biological diversity in the Party of import, taking also into account risks to human health, shall not prevent that Party from taking a decision, as appropriate, with regard to the import of living modified organism . . . in order to avoid or minimize such potential adverse effects." Jan. 28, 2000, Conference of the parties to the Convention on Biological Diversity (Cartagena Protocol on Biosafety) concerning the safe transfer, handling and use of living modified organisms resulting from modern biotechnology, art. 10ยง6. 10Second North Sea Declaration:

In order to protect the North Sea from possibly damaging effects of the most dangerous substances . . . a precautionary approach is addressed which may require action to control inputs of such substances even before a causal link has been established by absolutely clear scientific evidence.

Ministerial Declaration Calling for Reduction of Pollution, Nov. 25, 1987, 27 ILM 835.

Third North Sea Conference:

The participants . . . will continue to apply the Precautionary Principle, that is to take action to avoid potentially damaging impacts of substances that are persistent, toxic, and liable to bioaccumulate even where there is no scientific evidence to prove a causal link between emissions and effects.

Final Declaration of the Third International Conference on Protection of the North Sea, Mar. 7-8, 1990. 1 YB Int'l Envtl Law 658, 662-73 (1990).

11"Where an activity raises threats of harm to the environment or human health, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically. In this context, the proponent of an activity, rather than the public, should bear the burden of proof (or the safety of the activity)." Wingspread Statement on the Precautionary Principle, January 1998. 12Activities which are likely to pose a significant risk to nature shall be preceded by an exhaustive examination; their proponents shall demonstrate that expected benefits outweigh potential damage to nature, and where potential adverse effects are not fully understood, the activities should not proceed. UN GA RES 37/7, World Charter for Nature (1982), Principle 11 (b).