Prof Peter Saundersexposes
major misconceptions and misrepresentations perpetrated by opponents
No definitive statement exists but there is a reasonable consensus
There is no
definitive statement of the precautionary principle, but there is a reasonable consensus
about what it says, at least among those who support it. The 1998 Wingspread Declaration
 is typical:
an activity raises threats of harm to human health or the environment,
precautionary measures should be takeneven 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. The process of
applying the precautionary principle must be open, informed and democratic and
must include potentially affected parties. It must also involve an examination
of the full range of alternatives, including no action.”
European Commission in 2000 expressed it less succinctly , but it contains
the key phrase at the beginning:
Precautionary Principle applies where preliminary objective scientific
evaluation indicates that there are reasonable grounds for concern …” (italics
statements of the principle by those advocating it or proposing to use it, are essentially
similar. The principle is to be applied when (a) there is scientific evidence
for a threat to the environment or to health, but (b) the evidence, while
sound, is not conclusive. What is crucial is that there must be a prima
facie scientific case for a threat. If there is not, then the principle
does not apply, though of course any innovator should
try to identify possible hazards as a routine part of the process of
If there is, then we do
not have to wait until we are certain about the hazard before we can take
measures to mitigate or avoid it. The precautionary principle states that we
are permitted to act on the basis of evidence that is not conclusive. It
does not, however, say that we are obliged to. What, if anything, we
actually do is a matter for judgment on the basis of the evidence that we have
in front of us.
burden of proof is set to protect health & environment
precautionary principle is something like the burden of proof. In a civil court
the playing field is level, but in a criminal court it is deliberately not. The
defendant is not required to prove his innocence; it is for the prosecution to
prove him guilty beyond reasonable doubt.
lack of balance is deliberate. Courts are supposed to convict the guilty and
acquit the innocent. In an imperfect world that isn’t always going to happen, and
the legal system has to allow for when it doesn’t.
are two different ways in which things can go wrong, just like Type I and Type
II errors in statistics. The view that we as a society have come to is that
while it is undesirable that a crime should go unpunished, it is far worse for
an innocent person to be convicted. So we shift the balance to make it less
likely that will happen, which naturally means that we have to accept a greater
probability that a criminal will be set free.
the same way, when we act on the basis of evidence that is not conclusive, we
are saying that we have reason to be concerned that something is hazardous and
we are sufficiently worried about the consequences that we are willing to go
without it, or at least to delay its introduction until we have more evidence.
the burden of proof nor the precautionary principle is an algorithm for
decision making. A jury still has to decide whether the defendant is guilty
beyond reasonable doubt – and even what they are prepared to accept as “reasonable
doubt”. In the same way, even if we accept the precautionary principle, we
still have to weigh up the evidence as best we can, and we still have to decide
how much reassurance we are going to require before we allow something to
proceed. As in ordinary risk assessment, an important factor in this is how
much we believe we stand to gain if it does go ahead.
There are a
lot of criticisms of the precautionary principle around; let us deal with them
at the outset.
Ill-defined – Critics sometimes complain
that there are so many definitions of the precautionary principle that it
cannot be taken seriously. In fact, those that are not covered by the description
above come from opponents, each setting up his or her own straw man to
knock down. Then, to add insult to injury, they say that anything with so
many different definitions is obviously too vague to be useful.
Vacuous – Some complain that the
precautionary principle does not lead to definite decisions. But that
isn’t what it’s meant to do. Like the burden of proof, it is something we
take into account when we are making decisions.
– Others, evidently believing that the precautionary
principle does lead to definite decisions, complain that because there can
be risks on both sides of an action, it can “ban what it simultaneously requires” . As
above, the answer is that the role of the precautionary principle is to
influence decision makers, not do their job for them.
weak – The
‘burden of proof’ in a trial does matter: people are acquitted who would
be found guilty if criminal trials were like civil proceedings. See below
for examples of where the principle could have a real effect. And while
some people say it is too weak, naturally there are others who claim it is
strong – Even
with the burden of proof on the prosecution, many people do get convicted.
In the same way, even if we adopt the precautionary principle, progress
will continue. Almost all innovations will proceed without being
challenged, just as they do now.
Anti-scientific – On the contrary, the
precautionary principle is all about science. For it to apply at all, there
must be scientific grounds for concern, and it then requires that more science
must be done to allay (or not) those concerns. Sweeping but unsupported
assurances that everything will be all right will not do.
excuse for protectionism
– Anything that can lead to a restriction can be used as an excuse for
protectionism. But at least here the innovator has an opportunity to
counter the objection, by providing real evidence that the concerns are
unwarranted, or at least outweighed by the advantages.
matters should be dealt with in the courts – This is really just another
version of the misunderstanding that the precautionary principle is an
algorithm for taking decisions, which it is not.
of the precautionary principle often make up alarming stories of how it could
stop progress dead in its tracks. Here is a typical example. “Imagine it is 1850 and the following version of the
precautionary principle is adopted: no innovation shall be approved for use
until it is proven safe, with the burden of proving safety placed on the
technologist. Under this system, what would have happened to electricity, the
internal combustion engine, plastics, pharmaceuticals, the Internet, the cell
phone and so forth?” 
only is this all a flight of fancy, it depends crucially on a “straw man”
version of the precautionary principle. The critics cannot
provide examples where the precautionary principle was applied and resulted in
losses. In contrast, it is easy to find real cases where lives and money were
lost because the precautionary principle was not applied.
principle would not have prevented Sir Walter Raleigh introducing tobacco into
Europe because at that time there was no evidence that it was harmful. We are
told that in the late 1940s, when Richard Doll and his colleagues were trying
to find out why lung cancer had increased, they had no idea that the cause was
tobacco. The most likely candidate seemed to be the great increase in motor
traffic during the War.
epidemiological studies provided strong evidence that smoking was an important
cause of lung cancer . The sceptics, above all the tobacco industry, refused
to accept this conclusion, demanding instead proof in the form of a clearly
demonstrated mechanism. As a result, while it has been widely known since about
1950 that smoking is dangerous, it was only much later that our governments took
any action. Had the precautionary principle been applied, they would not have
waited for the proof the industry was demanding. They would have started much
earlier to increase the tax on tobacco, ban advertising especially when aimed
at children, ban smoking in public buildings, and so on.
is obviously impossible to calculate how many lives would have been saved if governments
had not waited so long. For one thing, we cannot say at what point they would
have judged the evidence strong enough to justify going ahead over the
objections of the tobacco industry. But the WHO MPOWER report  estimates
that in the twentieth century, tobacco killed 100 million people. If we suppose
that only one per cent of those lives would have been saved if the
precautionary principle had led countries to act sooner, that is still a
million lives. That in itself is a sobering thought, but we can, if we prefer,
convert it into monetary terms by using the usual risk assessment valuation of
a life as six million US dollars. That gives a total cost of six trillion
dollars, massive even when compared with the amounts involved in bailing out
people probably believe that the danger of asbestos was discovered only 30 or
40 years ago and that action was taken as soon as it was. In fact, it was in London in 1898 that Lucy Deane, one
of the first “Women Inspectors of Factories” noticed that people who worked
with asbestos suffered more serious ailments than those who worked in other
dusty environments. She even found a reason why: asbestos particles are sharp .
the next hundred years, governments and the asbestos industry kept insisting
that there was no conclusive proof that asbestos was as dangerous as we now
know it is. They also maintained that there was no alternative for it, which we
also now know there is. They therefore only gradually restricted its use. It
was being installed in buildings in the UK as late as the 1970s, and it wasn’t
until 1998 – the 100th anniversary of Lucy Deane’s report – that it
was finally banned altogether in the UK and France.
asbestos as for tobacco, we cannot really estimate how much was lost by ignoring
the precautionary principle. We can, however, get an idea of the scale by
noting that in 2000 it was estimated that there were about a quarter of a
million deaths from mesothelioma yet to come in Europe alone. That
converts to about one and a half trillion dollars, not including all the deaths
in the twentieth century, or the rest of the world, or asbestosis, or other costs.
is something to bear in mind the next time someone complains about the
unreasonable cost of adopting the precautionary principle.
evidence of harm is conclusive, it is clear that action is called for. The
precautionary principle applies when there is scientific evidence but it is not
conclusive. It is therefore alarming to read the justification offered by Wallace
Hayes, the editor of Food and Chemical Toxicology (FCT)  for his unilateral
decision to retract the paper by Séralini and co-workers  on the harm caused
by Roundup herbicide and Roundup Ready maize. He admits that it was not
a question of fraud, serious error, plagiarism or an unethical experiment, the
only grounds for retraction specified by the Committee on Publication Ethics,
of which FCT is a member. Instead, he retracted the paper because in his
opinion the results are “inconclusive.” In other words, the precautionary
principle should be replaced by the principle that if evidence is inconclusive
it should be suppressed.
fact, the paper of Séralini and his co-workers is only one of a large number of
papers in which GM crops and the herbicide to which they are made tolerant have
been shown to be harmful both to health and the environment. There is no need
to apply the precautionary principle; taken as whole, the evidence is far from inconclusive. (See  Ban GMOs Now - Special ISIS Report,  The Bradford Hill
Criteria Applied to Climate Change & GMOs, SiS 45). That is why there is now an active campaign
condemning the retraction and pledging to boycott the journal publisher unless
and until the retraction is reversed  Open Letter
on Retraction and Pledge to Boycott Elsevier, SiS 61).
the precautionary principle does not stop anything.
On the contrary, it could well lead to creative alternatives and solutions. What
it does is prevent governments and regulators from deliberately ignoring a
strongscientific case by using the excuse that there is no proof of
danger. It prevents companies from insisting that they must be allowed to carry
on until absolutely conclusive scientific proof is available.
it is accepted, the precautionary principle makes it much more difficult for
companies to demand damages from regulators, as the Ethyl Corporation was able
to do when the Canadian government passed legislation banning the fuel additive
MMT . Because the Precautionary Principle shifts the burden of proof on to
the perpetrator, and given the doubts about MMT (there was already a partial
ban in the US) Ethyl would have been required to show that it was safe.
brought its case not under Canadian law but under the North American Free Trade
Agreement (NAFTA). There is a real danger that the proposed Transatlantic Trade
and Investment Partnership  will similarly undermine the precautionary
principle within the EU. Laws and regulations within a country (including an
entity such as the EU) have to be debated in public and are expected to reflect
the values of that country; international agreements are largely free of such constraints
and generally assign a high status to trade as a value in itself.
the precautionary principle were implemented, most innovations would proceed
without interference just as they do now. Some, however, would not. There
would be a cost attached to that, as there is in all regulation, but history
has shown us that the cost of ignoring warnings can be very great indeed.
earlier version of this article appeared in Policy Responses to Societal Concerns
in Food and Agriculture, published in 2010 by the OECD .
Notes and References
and Environmental Health Network. The Wingspread Consensus Statement on
the Precautionary Principle, 1998, accessed 4 December 2009, http://www.sehn.org/wing.html .
Doll R and Bradford Hill A. Smoking and carcinoma of the
lung. British med. J. 2, 1950, 739-748.
World Health Organisation. WHO Report on the Global Tobacco Epidemic, 2008
The MPOWER package. WHO,
Geneva, 2008. ISBN: 978 92 4 159628 2.
P, Gee D, MacGarvin M, Stirling A, Keys J, Wynne B and Guedes Vaz S (2002).
lessons from early warnings: the precautionary principle1896-2000 European
Agency, Copenhagen. ISBN 92-9167-323-4.
Séralini G-E, Mesnage R, Gress S, Defarge N, Malatesta
M, Hennequin D and de Vendômois JS. Long term toxicity of a Roundup
herbicide and a Roundup-tolerant genetically modified maize. Food and
Chemical Toxicology, 50, 2012, 4221-4231. http://dx.doi.org/10.1016/j.fct.2012.08.005
Saunders PT. The Bradford Hill Criteria applied to climate
change & GMOs. Science
in Society 45, 24-25, 2010.
Becker HA, Clark EA, Cummins J, Davidson RM, de Guzman
LE, DelGiudice E, Dotson RS, Exley C, Haffegee J, Ho MW, Huber DM, John B,
Mason R, Mendoza T, Novotny E, Oller JW, Palmer J, Pollack G, Pusztai A,
Samsell A, Saunders PT, Shiva V, Sirinathsinghji, E, Swanson N, Seneff S,
Tomlijenovic L, Zamora O. Open letter on retraction and pledge to boycott
in Society 61 (to appear).