The Precautionary Principle vs. Principled Precaution: What Role Does Science Play?

September 4, 2002

Much of the western world uses precaution as a fundamental element in establishing regulations concerning public health and safety. The growing trend toward assigning more weight to precaution is in part a reaction to perceived regulatory failures—such as damage to the ozone layer and the recent outbreaks of bovine spongiform encephalopathy—that have required post-hoc reactions. New technologies hold the potential of unforeseen consequences to human health and the environment. Thus, the theory behind the call for what is designated the "Precautionary Principle" is reasonable: it appeals to common sense to try to prevent harm, rather than to repair damage already caused.

Early proponents of the Precautionary Principle asserted that a "lack of full scientific certainty" should not be used as a reason for postponing cost-effective measures to prevent environmental degradation. Support for this precautionary approach was soon exported into the food arena, despite the fact that the regulation of foods and food packaging is distinguishable from the nature of managing environmental risks. Unlike environmental factors, which are not always predictable, risks associated with food products are well known, with scientific assessments of risk and exposure better understood and more readily quantifiable.

Along with the broadening scope of the Precautionary Principle, there has also been an increased tendency for its proponents to reject reliance on scientific evaluation in favor of more restrictive policies based more on speculation and public sentiment. Adding to the confusion is the fact that a universal definition of the principle itself remains elusive.

On the other side of the debate are those who believe precaution is currently blended into risk assessments at appropriate levels. They assert that reliance on science is essential, and that progress should not be impeded by risks that are only potential in nature.

Rational application of precaution, or "principled precaution," provides little cause for alarm. In fact, principled precaution has been an important component of regulatory risk management for centuries. Federal regulation of food in the United States began with the Pure Food and Drugs Act of 1906, with antecedents stemming back from European statutes. In the past century, the basis of federal regulation of food, the Federal Food, Drug, and Cosmetic Act, was passed in 1938, expanding safety requirements, followed by the Food Additives Amendment (1958), requiring manufactures of new food additives to establish safety, and then the Color Additive Amendment in 1960.

In addition to these regulations-which address general safety, adulteration and misbranding-additional precautionary measures have been enacted to enforce good manufacturing processes; manufacturing safety procedures (such as the Hazard Analysis and Critical Control Points system); and procedures for certifications (such as ISO 9000). In addition, risk assessments and toxicological studies are required as part of pre-market approval for food-contact substances.

In sum, a precautionary approach, based on a foundation of scientifically established safety assessments, has long been fundamental in the U.S. regulation of food and food-contact materials.

Thus, the theory behind the Precautionary Principle is already a part of the American regulatory scheme. Yet, no matter how principled the idea of precaution began, a philosophical trend is emerging whereby science plays an ever-decreasing role, succumbing to politics and public perceptions as the driving forces in regulation.

Too Much Precaution?

An extreme approach to the Precautionary Principle would support an open-ended evaluation of all potential hazards—even those without any indication of likelihood of harm. When proponents of such a Precautionary Principle become convinced that scientific certainty of no risk of harm is necessary before a new technology is approved, their goal becomes not only unreasonable, unattainable, and often undesirable, but impossible.

The Achilles' heel of blind adherence to the Precautionary Principle is that it is scientifically impossible to prove that a harm will never result from a product or activity. Further, any possibility of risk of harm does not necessitate the avoidance of that risk entirely. Complete avoidance of an innovation because of the possibility of associated risks leads to the risk of living without the innovation. We live with risk daily. Because of our acceptance of scientifically supported levels of risk, today we are living longer, producing more crops, and enjoying the fruits of innovation, such as cars, cell phones, and conveniently packaged foods. Without accepting some levels of risk, our lives would be considerably shorter due to lack of sanitation, vaccination, and pharmaceutical innovation, and we would be without countless products upon which we now rely.

A further flaw in an extreme application of the Precautionary Principle is that it allows regulators, without scientific evidence, to assume infinite risk potential, without considering benefit. Overlooked in that view is that, much as we cannot know every potential harm in advance, we also cannot know every possible benefit an innovative technology or product can provide. Of course, at the opposite extreme is the argument that no risk should be avoided unless it can be absolutely proved to have no benefit. Each extreme is equally undesirable. Rather, potential risks must be evaluated, as must the benefits, based on sound, quantifiable science. All agree that a degree of caution is desirable when regulating innovative technologies. However, it is irresponsible to impede progress without consideration of what level of caution is appropriate.

Risk needs to be analyzed in two separate, but related, stages: risk assessment and risk management. The purpose of risk assessment is to evaluate a potential risk using scientific data and models. Risk assessment is a way of quantifying potential adverse effects based on respected scientific principles, and predicting when and if harm would take place and under what conditions. Once a risk is identified, quantitative analysis is undertaken to approximate the number of people who might be exposed to the risk, how often this might occur, and the severity of the potential hazard. Further, an unbiased risk assessment will also evaluate alternatives to the potential hazard, as well as the peril of not accepting the given level of risk, thus forgoing the proffered benefits. Following this science-based assessment of risk based on quantifiable data, policy makers are then charged with the task of managing that risk.

Risk management is the process of deciding what should be done to minimize a risk or hazard. It is a policy-making tool, which takes into account the scientific assessment and quantification of the risk potential, while considering feasible alternatives, and appropriate policy and regulatory responses.

While people may naturally be risk-averse, society can only progress when we are willing to take on manageable risks. As we all know, most, if not all, drugs come with counter-indication warnings, as well as known possible side-effects. Clearly, the more serious the condition being treated, the more risk one is willing to accept in order to alleviate or treat symptoms. Perhaps even a risk of death can be deemed reasonable if that potentiality is low enough and the quality of a person's life is that much more enhanced by taking the drug. However, those same risks would not be acceptable for treating a minor or cosmetic condition. Rational, scientifically driven analysis of risk leads to principled precaution.

Scientifically based risk analyses are currently required as part of the regulatory paradigm by U.S. agencies. When evaluating new drug applications, food-contact notifications, and other health and safety regulatory submissions, regulatory approval is granted or denied based on the scientific results from safety assessments and known toxicology and exposure data. The standard of data review in Section 409 of the U.S. Federal Food, Drug, and Cosmetic Act is "reasonable certainty of no harm." This is an inherently precautionary standard based on scientific evidence, which differs significantly from the unattainable standard of certainty of no theoretically possible harm.

International regulation of food has also traditionally relied on scientific standards. The Codex Alimentarius Commission (Codex) was created in 1963 by the Food and Agricultural Organization of the United Nations (FAO) and the World Health Organization (WHO) to develop food standards, guidelines and related texts under the Joint FAO/WHO Food Standards Programme. Codex has established that its standards are to be based on sound scientific analysis, with consideration of other factors such as health protection and fair trade practices. The main purposes of this program are to protect health of the consumers and ensure fair trade practices, while promoting coordination of all work on food standards undertaken by international governmental and non-governmental organizations. Increasing international communication and the harmonization of regulations in the European Union serve to increase scientific knowledge and consensus. Now is not the time to abandon rational application of principled precaution in favor of a tendency toward extreme interpretations of the Precautionary Principle.

Theory Doesn't Hold Water

Beyond risk assessment and risk management, a third element, communicating risks to the public, presents special challenges for policymakers. It may be instructive to consider the results of an extreme precautionary approach to communicating the risks associated with a substance currently found throughout our environment.

Dihydrogen monoxide (DHMO), also known as hydric acid, is a colorless, odorless chemical compound widely found in food and food packaging. Its components are also found in a number of caustic, explosive, and poisonous substances, such as sulfuric acid, nitroglycerine, and ethyl alcohol.1

Despite the fact that DHMO is a constituent of many known carcinogens and is responsible for injury, death, and property damage all over the world, it is not listed on the U.S. Toxic Substances Control Act inventory. Yet studies have shown that inhaling even small quantities can cause death; prolonged exposure to DHMO in its solid form causes severe tissue damage; it contributes to soil erosion; and it is a major component of acid rain.

DHMO can be found in numerous food and food contact applications, including baby food and baby formula, carbonated beverages, and "all natural" fruit juices. It is also used as a preservative in grocery store fresh produce sections, and is used in the production of beer. In addition, cows are encouraged to ingest large quantities of DHMO, as studies show that it can lead to increased milk production. While governmental regulations do cover the addition of DHMO to milk after it leaves the cow, there is no such regulation of levels of ingested DHMO.

Those who adhere to the Precautionary Principle claim that citizens are disenfranchised when it is not clear who is deciding what level of risk is "acceptable," and thus unwitting consumers are exposed to chemicals like DHMO. The system in place in the United States, on the other hand, has repeatedly demonstrated not only a strong conviction toward precaution (as demonstrated by extensive safety data required by FDA for food and drugs), but it also has a history of responding to changing knowledge and circumstances.2

While legislators, businesses, and individuals can best make educated decisions based on scientific evidence, that is not to say that public perceptions and social policy have no place in risk management. In addition to working through elected officials, grass-roots education efforts are often undertaken to inform the public when it is perceived that a risk is too high.

Such an effort has been made to educate the public about the dangers of DHMO. After being informed that "Dihydrogen Monoxide is found in all forms of cancer, it is a major component of acid rain, if it is inhaled in its natural state it is often fatal, [and] in gaseous form it causes severe burns," surveys of people in the United States and Canada reported that the vast majority of those polled favor a ban on the substance.3

This call for a ban on DHMO—or as it is more commonly known, water—illustrates the challenges faced by policymakers charged with communicating risks to the public.

Balance Is Key

No one disagrees that precaution should be taken when approving new technologies in order to protect human health and the environment. However, the evaluation of risks and benefits must be based on quantifiable reliable data—not on fear and speculation.

Importantly, scientific assessments are not inflexible. As science and assessment methods develop, they can be used to ensure that products packaging our food, curing our diseases, and serving society in other ways are as safe as is reasonably possible. Emotion and desire to protect our families and environs are part of what drives our policy-makers to rely on scientific research, with the goal of serving society while protecting us from irresponsible damage. While public perception and preference is certainly a factor to be considered in the management aspect of risk, it must play a balanced and appropriate role.

Rational application of precaution is not a threat to U.S. policy, and suggestions of additional products and technologies to which a precautionary approach might be applied—such as regulation of dietary supplements—should be considered. Responsible health and environmental regulatory policy demands examination of appropriate responses and alternatives to risks. Reliable scientific evaluations of products provide risk managers a sound basis on which to assess benefits as well as risks, and a properly defined and applied Precautionary Principle is an appropriate element of risk management.

If innovation is accompanied by risks that are too high for public well-being, then through the use of sound science, along with principled precaution as a basis for regulation, that technology will not be approved, the drug or pesticide will not be marketed, and the packaging will not be sold.

On the other hand, if we live by an extreme interpretation of the Precautionary Principle whereby "precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically,"4 we could well end up with a policy that would allow for an attempt to ban water. No new development can survive the impossible burden of proving no potential for harm. Thus, the Precautionary Principle, without well-defined limitations, may result in too much precaution. Without principled precaution, we will impede progress toward a safer and more plentiful food supply, better and faster communication, safe and comfortable shelter, and longer, healthier lives.


1For more information on DHMO, see

2Last year, more than 40,000 people died in the United States as a result of automobile accidents. Yet, as a society we have determined that this risk is acceptable. Even knowing the extent of the risk, the vast majority of adults have determined that the risk is worth the convenience or necessity driving a car. Periodically, the toll of deaths and injuries exceeds what is "acceptable," and through our democratically elected representatives, legislation is enacted to adjust speed limits, require seatbelts, and enact other precautions as science, statistics, and societal needs are better understood.

3For results, see

4This statement of the principle was formulated at the 1998 Wingspread Conference on the Precautionary Principle, and is a definition frequently cited by proponents.