Center for Progressive Reform

CPR Perspective: The Precautionary Principle

by then-Member Scholar Christopher Schroeder

he Issue
How should we address actions that might damage the environment or people’s health when we are uncertain about how much and what kinds of harm the action might cause – or even if it will cause any harm at all?


Living with risk and uncertainty is not optional. The actions society takes to address risk and uncertainty are. Until the 1970s, a reactive approach to the risks and uncertainty of industrial pollution and workplace safety predominated in the United States and other Western societies. Under this approach, risk creators are held responsible when their actions unreasonably cause harm to humans and their property, but not otherwise. Society accepts risky actions until solid evidence exists that those actions are causing harm. This approach gives risk creators two distinct advantages:

  • People exposed to risky actions must bear the risks of such actions until they cause (or are nearly certain to cause) harm to health or the environment.
  • The people exposed to risk bear the responsibility for demonstrating that actions caused harm.

In the last three decades, the reactive approach has been replaced by the precautionary approach in several key arenas. For example, when Congress wrote such statutes as the Clean Air Act, it included the mandate that EPA issue standards that protect health with an “adequate margin” of safety, recognizing that it is impossible to determine exactly how much pollution is “safe” or acceptable.


The full implications of the precautionary approach are still developing, and when people have tried to reduce the approach to a statement of principle, various versions have been created. The 1992 Rio Declaration on Environment and Development states the principle this way:


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.


The EU Treaty adopts the precautionary principle as the guide for environmental policy, and a recent communication by the European Commission elaborates the principle as follows:


The precautionary principle applies where scientific evidence is insufficient, inconclusive or uncertain and preliminary scientific evaluation indicates that there are reasonable grounds for concern that the potentially dangerous effects on the environment, human, animal or plant health may be inconsistent with the high level of protection chosen by the EU.


These formulations are not interchangeable, and many other non-identical expressions of the precautionary principle have appeared in international treaties, statements of government policy and in law. When contrasted with the reactive approach, however, all statements of the precautionary principle share a common feature: they authorize government to intervene with respect to risky actions while there is still uncertainty about whether those actions will cause harm.


The precautionary approach alters both of the advantages that risk creators enjoy under the reactive approach. Under the precautionary approach:

  • People exposed to risk can ask for precautionary actions to be taken before risky actions cause harm.
  • Once some preliminary basis for taking precautionary action exists, risk creators bear the responsibility of showing that actions are safe, or at least acceptably risky.

The precautionary approach also protects a wider range of interests than the reactive approach, which limits its range of protected interests to harm to humans and to things humans own. In contrast, all formulations of the precautionary principle extend to biotic and ecological interests, as well as to future generations.


What People are Fighting About


In one form or another, the precautionary principle has become a fixture in environmental and health and safety debates in Europe and in the negotiation of international agreements. It is on the verge of being accepted as a principle of international law. The term “precautionary principle” is not often heard in American policy debates, although the precautionary approach has been a fundamental element of American environmental policy for decades. The devil dwells in its details, however, and one set of controversies involves fleshing out those details. To make the principle specific enough to inform decision-making, three elements need to be specified:

  • The principle rejects waiting for definitive proof of a causal connection between actions and harm, but short of such proof, what kind and quantity of evidence— and evidence of what kind of harm—is required to trigger precautionary action?
  • The principle speaks of precautionary action, but what sort of action is appropriate—product bans, product labels, use restrictions, further experimentation, reductions in the amount or frequency of the risky action, or something else?
  • The principle authorizes precautionary action in advance of accepted evidence of harm, but how temporary or final is the decision, and when should it be revisited?

Each of the elements sparks debate both inside and outside the environmental movement. The main battlegrounds, however, have industry and business interests on one side and advocates of better environmental, health and safety protection on the other.


What’s At Stake?
Our commitment to policies that protect against severe damage to the environment and public health before harm has already been caused.

The United States and U.S. companies have had notable conflicts with other countries in which the precautionary principle has played or is playing an important role. Genetically modified foods have raised fears of “frankenfoods” and calls to invoke the precautionary principle in Europe, with companies like Monsanto seen as the chief culprits in disseminating foods there. The EU banned the import of U.S. hormone-fed beef on the basis of the precautionary principle, only to have the WTO Appellate Body rule this was an impermissible trade barrier.


In American environmental policy circles, there is a general sense that greater recognition of the precautionary principle will mean more regulation and tighter controls. Accordingly, a concerted effort has been mounted to discredit the whole idea as an illogical principle that is self-contradictory, ignores the risks of regulation, demands the impossible, and is anti-scientific. These last two objections—“anti-scientific” and “demands the impossible”—go to the heart of the debate.


Opponents of the precautionary principle claim that its supporters want to impose regulatory measures supported by nothing more than vague and baseless fears, regardless of whether there is evidence to support their fears. In the case of genetically modified foods, for instance, very few studies have shown that any particular genetically modified food produces adverse environmental or health effects. One publicized study did indicate that pollen from a type of genetically modified corn damaged monarch butterfly larvae feeding on milkweed onto which the corn pollen had been placed. This suggests a risk to the monarch from corn pollen borne by the wind onto milkweed, which is common near corn fields. This study has been criticized on methodological grounds, and debate continues over this adverse effect. Other studies looking at other effects of pollen from genetically modified pollen have found no negative impacts.


The problem is that absence of evidence is not evidence of absence. Further investigation might reveal that certain crops do cause adverse environmental effects. Consider that around 30 percent of the corn sold in the United States comes from genetically modified seed. If some other genetically modified food with just a fraction of that market share turned out to interact destructively with its environment, the consequences could be dire. Because the precautionary principle urges action when studies have not shown a causal relationship, opponents of the principle allege that it is anti-science. No controversy in which the precautionary principle has been seriously invoked, however, involves a situation in which concerns are baseless. In the genetically modified case, we know of many instances in which a new species or variant has been introduced into an environment with unanticipated consequences—ask any southerner about kudzu or any Californian about the eucalyptus tree. Genetically modified crops are human-made variants, new to their surroundings in similar ways. The discovery in September, 2000 that Starlink corn was unlawfully present in U.S. foods demonstrates that genetically modified plants are not easily controlled. Beyond such environmental effects, there are sound theoretical reasons to worry that genetically modified foods might cause adverse health effects in humans, as well—such as producing or exacerbating allergic reactions—even though investigations of specific modified foods have not shown such effects. Concerns about potentially unanticipated, and possibly disastrous, consequences are not baseless.


Insisting on more science before government can intervene is effectively an attempt to push us back to the reactive approach, forestalling action until science has proven a causal connection between a risky action and harm. In situations of scientific uncertainty of the kind found at the heart of most environmental, health and safety controversies, however, the reactive approach sets up perverse incentives. The risk-takers are often best positioned with respect both to knowledge and to resources to investigate the potential hazards of their actions. By saying it is acceptable for risk-takers to proceed unrestrained until harm has been proven, the reactive approach creates disincentives for them to undertake such investigation. Far from being anti-science, the precautionary approach encourages the development of more scientific knowledge by switching those incentives, now making it worth the risk-takers’ while to reduce scientific uncertainty, thereby relieving whatever restraints might be put in place in the name of precaution. (The importance of having environmental policy that creates the right incentives for producing more knowledge is discussed in the CPR Perspective on Environmental Enforcement.)


Opponents of precaution object, however, that they will never be able to prove that an action or product poses no risk whatsoever, and so will never be able to prevent or relieve precautionary restraints adopted in the face of uncertainty. So, they say, the precautionary principle demands the impossible. This, too, is not a convincing objection to the precautionary approach. The question that most of us end up asking about risk—and the appropriate one for society to ask—is whether risks are acceptable. The precautionary principle turns that question into a public question by making the issue of acceptability subject to public decision-making processes. This permits dimensions of people’s concerns about risk that are not well incorporated into quantitative analyses of risk to be accorded their due in the decision-making process. People become more concerned about risks when they threaten irreversible consequences, when they are unevenly distributed in the population, when they are involuntary, or when they exhibit a number of other characteristics. By shifting the burden of explanation as to why it is acceptable to expose people to risks in the face of uncertainty onto the risk-taker, the precautionary principle fosters more democratic methods of determining what risks are acceptable, in which the elements of risk that matter to people can be acknowledged.


CPR's Perspective

Decisions on the Table
-What t ype of evidence of potential harm needs to exist prior to taking preventative action?
-What risks is our society willing to accept and what risks are we not willing to accept?


A concerted effort is now underway to block application of the precautionary principle to the protection of public health, workplace safety, and the environment. An assault on the precautionary approach is one of the battlegrounds for that effort, as is the debate over the use of good science versus bad science, as well as the efforts to implement the Data Quality Act in ways that will burden agency decision-making and reduce public access to information. (See the CPR Perspective on Data Quality for more on this new law.) John Graham, head of the White House regulatory office, has gone so far as to call the precautionary principle “a mythical creature, kind of like a unicorn.”


CPR believes that the precautionary approach ought to be central to our thinking and to our policy-making regarding health, safety and environmental issues. Public policy-making needs to be more amenable to citizen participation and involvement, it needs to create incentives to acquire more information about potential risks, and it needs to respect the reality that human manipulation of the environment can pose substantial threats to the biosphere and to future generations.


CPR also believes that more caution can be achieved without damaging our ability to innovate and thus to find ways to serve human needs. In fact, a precautionary approach toward some technologies almost always stimulates research and innovation with regard to other technologies that pose fewer risks. California’s insistence that the internal combustion engine be eliminated from 10 percent of the automobile fleet sold in California in 2004, for instance, has stimulated research into battery and fuel-cell powered vehicles that would not have occurred without the California requirement. Battery powered vehicles still have limited potential, but new steps in use of the fuel cell in vehicles shows promise to produce a much more benign form of personal travel, which some have called “sustainable mobility.”


There are many issues of detail to be worked out in implementing the precautionary approach, and the precautionary principle will most likely prove to be a number of different principles applied in different circumstances. However those details work out in specific instances, the foundational precept that gives primacy in policy debates to those upon whom risk is imposed contrasts markedly with the reactive approach of giving primacy to people who impose risk on others. That precept lies at the heart of the precautionary principle and CPR believes it to be fundamentally sound. It ought to motivate us to take responsible precautionary actions in response to risk and uncertainty.

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© Center for Progressive Reform, 2013