Merchants of Doubt: Why isn’t our government regulating pesticide use?

A few months ago, we had a long email “conversation” with a reader who is opposed to the destruction of our urban forest, but does not believe that pesticides are harmful to the environment. He is an intelligent and well-informed person and we were intrigued by some of the arguments he used.  We read and considered every resource he sent in support of his opinion.  Then we read the resources suggested by our collaborators with greater knowledge of pesticides.

Glyphosate application, Glen Park, San Francisco.
Glyphosate application, Glen Park, San Francisco.

We have decided to report some of what we learned because of the recent decision of the World Health Organization (WHO) to classify glyphosate as a “probable human carcinogen.”  Glyphosate is the herbicide used most often by land managers to eradicate plants they consider “invasive.”  It is also considered the least toxic of the many herbicides they use.  Some countries are reacting to the WHO decision by banning use of glyphosate.  The Marin Municipal Water District has announced that it will quit using glyphosate (and other herbicides) to eradicate non-native plants on Mt.  Tamalpais.  The City of San Francisco recently announced that it has reclassified glyphosate from Tier II (more hazardous) to Tier I (most hazardous)Why isn’t our federal government or our land managers in the East Bay questioning the use of this pesticide?  Our reading in the past few months answers this question. 

Merchants of Doubt

Merchants of Doubt (1) is about a small group of people (mostly men) who have influenced public policy in the past 60 years by undermining the science upon which these policies should be based.  They were physical scientists who were involved in the development of weapons during WW II and the Cold War that followed.  As such they were deeply committed to militaristic solutions to international threats and they perceived communism as America’s greatest enemy.  It follows that they were equally committed to our capitalist economic system which is the antithesis of communism.  They perceived government regulation of business interests as a threat to capitalism.  Here are some of the public policy issues in which they have been influential:

  • Merchants of DoubtAfter WW II many scientist who participated in the development of nuclear weapons became advocates for arms control because they predicted dire consequences of their use, such as the nuclear winter that would decimate life on Earth. The Merchants of Doubt stepped forward to undermine the effort to disarm the nuclear arsenal by attacking the predictions of their opponents.  They played a similar role during the Reagan administration when most scientists did not consider the Strategic Defense Initiative (AKA Star Wars) technically feasible.   With the backing of the Merchants of Doubt, the development of SDI was funded despite the fact that it is unlikely to be useful in actually defending against nuclear missile attack.
  • In 1953, laboratory tests on mice were the first scientific evidence that smoking causes cancer. The manufacturers of cigarettes engaged in a “massive and ongoing fraud to deceive the American public about the health effects of smoking” (1) and their efforts were aided and abetted by the Merchants of Doubt who provided much of the “scientific” cover that delayed the regulation of cigarettes for decades.   When laboratory tests and epidemiological data indicated that second hand smoke is more toxic to innocent bystanders than to those who smoke, the Merchants of Doubt stepped forward again to delay the bans on smoking that are now in place in most public places.
  • The Merchants of Doubt have played a similar role in preventing or delaying government action to address several environmental issues: acid rain which was killing the world’s forests; depletion of ozone in the atmosphere which results in an increase in the incidence of skin cancer; and currently climate change. 

How could such a small group of people be so influential when the science of these issues is so conclusive?  Here are some of the reasons why the Merchants of Doubt were successful in delaying and in some cases, preventing government regulations to address these issues:

  • Science is rarely conclusive. It is primarily a process of hypothesis testing, and retesting until the weight of evidence is sufficient to outweigh uncertainty.  If doubt is continually put on the scale, certainty is harder to achieve.  That was the strategy of the Merchants of Doubt.  They didn’t need to disprove the evidence.  All they needed to do was to cast doubt and keep demanding that more evidence was required to overcome uncertainty.  In most cases, doubt was overcome eventually, but the Merchants of Doubt were successful in delaying public policy on most of these issues for decades.  Climate change remains our biggest issue for which there is insufficient public consensus to enable public policy to address it.  The economic interests vested in the industries contributing to climate change are so big, wealthy, and therefore influential that it remains to be seen if or when we will finally be able to address the causes of climate change.
  • The media has participated in the promulgation of doubt.  The “fairness doctrine” requires that responsible journalists and broadcasters represent dissenting views.  For example, every time there was a broadcast about the health dangers of smoking, tobacco companies and their allies demanded equal time.  We no longer see such “balanced” coverage of smoking.  The evidence is so overwhelming that government regulation was finally achieved and advertising of tobacco products is strictly limited.  We seem to be moving in that direction on media coverage of climate change, but we still see dissenting views reported at a time when scientific evidence no longer justifies the representation of that viewpoint.
  • The most disturbing reason why the Merchants of Doubt were successful was that government was actively collaborating with them. They were represented on government panels, review bodies, task forces, etc.  This often put them in a position to disarm, distort, or censure scientific opinion on all of the issues in which they were actively engaged.

A word about conspiracy theories is required.  We are generally deeply suspicious of conspiracy theories.  We realize that this brief summary of a 274-page book with 75-pages of citations and footnotes, written by two science historians probably sounds like a conspiracy theory.  The fact that the Merchants of Doubt (who are identified in the book*) weren’t much more than a handful of people may seem particularly fanciful.  We can only say in defense of our summary that you should read this book before reaching the conclusion that it is not possible for a small group of influential people to control public policy to the extent that Merchants of Doubt informs us they did.  The authors of Merchants of Doubt make a convincing case.  There is also a documentary movie (available for rental on Netflix) based on the book, which should help you decide if you find their report credible.

Pesticide regulation in the US

Silent springYou may be wondering what all this has to do with pesticides, so let’s turn to that issue.  The story of pesticide regulation in the US begins with the publication of Silent Spring in 1962, in which Rachel Carson informed us that the widespread use of DDT by agriculture was having a devastating effect on wildlife, particularly birds.  She was immediately attacked by the manufacturers of pesticides as a “hysterical female,” but after 10 years of research which proved her point, DDT was finally banned for agricultural use in the US in 1972, shortly after the creation of the Environmental Protection Agency.  Fifty years later, DDT remains one of the few pesticides banned in the US for agricultural use.

You might think that is the end of the story for DDT, but you would be wrong.  The Merchants of Doubt created foundations to carry their message and receive tax-deductible “donations” from the corporations they are protecting.  In 2007, these foundations launched a belated attack on the banning of DDT.  For example, The Competitive Enterprise Institute—which was instrumental in defending tobacco– says on its website, “Millions of people around the world suffer the painful and often deadly effects of malaria because one person sounded a false alarm…That person is Rachel Carson.” (1)  This accusation was repeated by several other “foundations” and published by the mainstream press.  Michael Crichton, the author of novels portraying global warming as a liberal hoax, quotes one of his fictional characters as saying, “Banning DDT killed more people than Hitler…It was so safe you could eat it.”  Apparently fictional characters also have fictional digestive systems.

Why the belated attack on Carson decades after the issue has been resolved to the public’s satisfaction?  “In the demonizing of Rachel Carson, free marketers realized that if you could convince people that an example of successful government regulation wasn’t, in fact, successful—that it was actually a mistake—you could strengthen the argument against regulation in general.” (1)

There is no truth to this accusation that banning DDT caused millions of deaths by malaria:

  • The ban of DDT in the US did not obligate any other country to ban DDT. In fact, many countries continued to use DDT long after the US banned it. 
  • By the time DDT was banned in the US, it was no longer effective on many insects, including the malaria-carrying mosquito for which DDT was used most heavily during WWII. Insects have short lives and huge populations.  Therefore, they evolve much more quickly than most animals.  This is one of the strongest arguments against pesticide use, yet the public does not seem to understand that the more pesticide we use, the more quickly they become ineffective. Both insect and plant pests evolve resistance to pesticides quickly. 
  • Malaria control was not achieved solely with pesticides. Draining swamps and wetlands, removing standing pools of water, using window screens and bed nets, etc. have proven more effective than widespread spraying of pesticides.


A small group of people with scientific backgrounds have succeeded in confusing the public about many critical issues that threaten our health and our environment.  Their desire to prevent government regulation has trumped their commitments to science.  In any case, they are presuming to judge scientific issues outside their expertise.  They did not have the credentials to deny the reality of climate change, for example, yet they were given the podium by our government and our media.

In our next post, we will look at some of the specific arguments used to disarm criticisms of pesticide use and respond to them with the help of an excellent book, Pandora’s Poison by Joe Thornton.

*Individuals identified by Merchants of Doubt as purveyors of misinformation intended to prevent regulation of environmental and health risks:  Frederick Seitz, Robert Jastrow, William Nierenberg, S. Fred Singer and others playing smaller roles.

(1) Naomi Oreskes and Erik Conway, Merchants of Doubt, Bloomsbury Press, 2010

4 thoughts on “Merchants of Doubt: Why isn’t our government regulating pesticide use?”

  1. So well written, as always. Your exposure of these truths is so important. Thank you for the investment of time and energy that you continue to make.



  2. Regarding the reclassification of glyphosate to probable here are some opinions.

    “Expert reaction to carcinogenicity classification of five pesticides by the International Agency for Research on Cancer (IARC)” Most of them conclude the upgrade to probable is not justified by the evidence.

    In conclusion of this re-evaluation process of the active substance glyphosate by BfR the available data do not show carcinogenic or mutagenic properties of glyphosate nor that glyphosate is toxic to fertility, reproduction or embryonal/fetal development in laboratory animals.

    The IARC conclusions published in Lancet Oncology contradict the world’s most robust and stringent regulatory systems – namely the European Union and the United States – in which crop protection products have undergone extensive reviews based on multi-year testing and in which active ingredients such as glyphosate and malathion been found not to present a carcinogenic risk to humans.”

    1. Thank you for these links, which I have read. I consider them symptomatic of the very phenomenon we are reporting in this article: the regulation of toxic chemicals is effectively prevented by casting doubt on their toxicity.

      In the case of glyphosate, the IARC which recently classified it as a “probable human carcinogen” did so by evaluating hundreds of laboratory and epidemiology studies. Because these studies do not all point in the same direction, the decision was ultimately a judgment call. Those who choose to disagree with that reassessment can easily point to the studies that point in their direction. But that choice is also a judgement call and not inherently superior to the conclusion of the IARC.

      When making the choice about whom or what to believe, one evaluates the sources of information. We therefore provide our readers with the following observations about the sources you cite:

      The mission statement of European Crop Protection states: “We represent our industry in relevant European fora, towards our major stakeholders and the wider public; We lead and co-ordinate a European network of member companies and national associations, who act as our local representatives.” In other words, this is an organization that represents the interests of the agricultural industry in Europe. It is in the economic interests of agricultural industry to continue to use pesticides and therefore the regulation of pesticides is antithetical to their interests.

      BfR is the German equivalent of the assessment functions of several of our federal agencies: USDA, EPA, and FDA. It is the function of these government organizations to assess the risks of pharmaceuticals and other chemicals in our environment. If you believe that our government agencies are doing an adequate job of performing this task, you might consider BfR a credible source of information. We do not believe our US agencies are performing these duties in the interests of public health. We believe their primary goal is the protection of industry interests. German agencies are likely subject to the same pressures, so we evaluate that source of information accordingly.

      Science Media Center was harder to evaluate. We note that experts quoted in the article you cite are not unanimous in their criticism of the IARC decision. We also note that a page listing their funding sources (which was cited by Wikipedia) has been removed from their website.

      We decided to discount this source of information after reading their assessment of the article published last week in the New England Journal of Medicine about GMOs and herbicide: “GMOs, Herbicides, and Public Health,” by Philip Landrigan and Charles Benbrook. NEJM is America’s premier medical journal. It has rigorous standards for identifying and discarding studies in which there is evidence of conflict of interest, such as studies funded by pharmaceutical companies.

      Science Media Center attempts to discredit this article by claiming that it damns all GMOs. The article does no such thing. It is critical only of the GMOs that are enabling the indiscriminate use of pesticides by agriculture. It is particularly concerned about the anticipated approval of a new combination of pesticides (glyphosate and 2,4D) which will be capable of killing the super weeds that have evolved as a result of the indiscriminate use of glyphosate. The article also provides specific reasons why tests of this new product have been entirely inadequate and it recommends against the approval of this toxic combination of two “probable/possible” carcinogens.

      In conclusion, we choose to discount these sources of criticism of the IARC assessment of glyphosate as a “probable human carcinogen.”

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