The Precautionary Principle
by Christopher Schroeder
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In the last three decades, the reactive approach has been replaced by the precautionary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
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
- 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
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
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
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.
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
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
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.