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What's wrong with our nation's approach to regulating pesticides

Jennifer Sass

Posted January 17, 2011

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Pesticides are regulated much more strictly than industrial chemicals under U.S. law, requiring a significant amount of safety data before being registered for use, and undergoing a registration review process every 15 years in case new data on potential harm has come to light. Nonetheless, there are weaknesses, loopholes, and flaws in all aspects of the process from legal requirements to implementation to enforcement and oversight. Here I've put together some of the most endemic widespread and fundamental weaknesses with the process, in the hopes that they can be addressed by the Office of Pesticide Programs (OPP) staff at the Environmental Protection Agency (EPA).

Failure to test for known risks

Pesticide manufacturers (registrants) are required to supply a significant amount of safety data on their products to the government before their products can be registered, including acute, chronic, sub-chronic, and ecological toxicity tests on multiple species and both sexes, as well as basic chemistry data.[i] Nonetheless, most legal limits for pesticides are based on “toxic ignorance”, not on safety. That is, toxicity studies required to register a pesticide do not include many disease endpoints such as immune system toxicity, endocrine or hormone system disruptions, learning deficits, or chronic diseases such as Parkinson’s Disease. Yet, all of these have been linked to pesticide exposure in the peer-reviewed scientific literature (see reviews here and here).[ii]  Further, pesticides are only reviewed every fifteen years, leaving long lag times between science and regulations.

Register now, test later: The problem of conditional registrations

An analysis by NRDC revealed that the majority of pesticide products are approved for use as a ‘conditional registration’ before all required studies are completed (see NRDC comments on nanosilver here).[iii] Completion and review of these studies may occur years later, if at all, with little public oversight.

Industry science versus academic science

The truth is that when new studies are published that indicate the need for more protective exposure limits, the pesticide labels are stuck in time. This is because the exposure limits are set based on the data supplied by the industry (the registrant). This restrictive and biased use of science is defended by industry claims that only the industry data is conducted according to pre-validated study designs required for the registration process and performed in Good Laboratory Practices (GLP)-certified labs.[iv]  However, study designs are often very outdated and do not reflect the current science, most sensitive disease endpoints, or chronic disease outcomes. Moreover, GLP standards were imposed on industry labs during the 1970’s after flagrant violations and fraud were identified.[v] GLP requirements are designed to set a baseline of cleanliness, animal care, and record-keeping; they are not associated with higher quality research, proper study design or correct statistical analysis. In contrast, academic research which has found pesticides to be harmful has been published in respected scientific journals and relies on the peer-review process and public accessibility to uphold scientific quality.

Failure to promote reduced risk alternatives

When registering pesticides, there is no requirement for EPA to consider reduced risk or non-toxic alternatives or lower use/exposure levels.  While registrants have an incentive to approval the greatest potential uses of their product, EPA does not assess the availability of safer alternatives when considering product registration.

Failure to regulate to reduce over-use

The amount of pesticide residue that is legally allowed on our food, called a ‘tolerance’ is set based on how much pesticide a person can ‘safely’ consume and still meet the EPA standard of ‘reasonable certainty of no harm’, considering aggregate (from other uses of the same pesticide) and cumulative (uses of other pesticides in the same mode of action family) exposures. This may be much higher than a pesticide needs to be to have its desired pesticidal effect. It is likely that pesticides most could be used in far less amounts and still be effective. Unfortunately, this is not in the interests of the companies that manufacture and sell the pesticide, and negotiate the registration with EPA.

History of post-market recalls after decades of harm

As we learn more about the harmful effects of pesticides, ones that had been approved may later be restricted or even cancelled. For example, in June, 2010, after many years of public comments and even a petition and a lawsuit by NRDC, endosulfan, a highly persistant toxic pesticide is finally being cancelled due to its “unacceptable neurological and reproductive risks to farmworkers and wildlife” according to the EPA (see my blog here).[vi] Unfortunately, these actions come after decades of harmful use. Other examples are:  

  • Chlorpyrifos:  Scientific studies have reported that exposure to chlorpyrifos during pre-birth and early life stages is associated with poor birth outcomes and long-term neurobehavioral deficits. For these reasons, since 2001, residential uses of chlorpyrifos were all cancelled, resulting in a reduction of over 6 million pounds annually from people’s homes. This action has been associated with a 66% reduction in poisonings since 1995. However, approximately 10 million pounds are still used annually on corn, in orchards, and on other vegetable row crops. Its breakdown products have been detected in the bodies of three-quarters of the US population.
  • Diazinon: The phase-out of over 11 million pounds annually of non-agricultural uses of diazinon took ¾ of diazinon off the market. This was correlated with a measurable reduction of diazinon in streams of between 20 and 40%, according to government geological survey data. Unfortunately, although EPA cancelled all non-agricultural uses of diazinon (11 million pounds annually), it left agricultural uses that total approximately 3 million pounds annually.

Failure to consider farm children

Farm children, especially the children of farmworkers, come in contact with pesticides through residues from their parents’ skin and clothing, soil and dust tracked into their homes, contaminated soil and other surfaces in areas where they play, food eaten directly from the fields, drift from agricultural pesticide applications, contaminated well water, and breast milk from exposed parents (see for example here and here.[vii] In December, 2009 EPA proposed a policy to consider the unique risks to the children of farmworkers. However, as of January, 2011 this policy has still not been finalized.[viii]

Illegal uses

All of the above limitations in pesticide regulations presume legal use of pesticides. However, we know that illegal uses take place routinely, albeit not always intentionally; for example, the use of old stores of pesticides that have since been banned, or the use of pesticides according to last year’s practices even though current labels have been updated to reflect that application rates have been lowered or buffer zones have been increased. Many stores and small outlets sell pesticides that have been banned, or maybe that have never been legal in the US, for residential uses including folk remedies and other off-label illegal applications.[ix] These uses of pesticides can be dangerous, and even deadly.


[i] A summary of data required to register pesticides is here:

[ii] An overview of health effects associated with pesticides is provided in the introductory remarks and study findings of the NIH Agriculture Health Study here:

See also Marina Bjørling-Poulsen et al Env Health 2008

[iii] Comments from the NRDC on the proposed conditional registration of a pesticide product HeiQ AGS-20, containing nanosilver. Sept 10, 2010. Docket ID # EPA-HQ-OPP-2009-1012

[iv] Comment from Dow Chemical company on why industry data is trustworthy:

[v] History of GLP here:

[vi] Jennifer Sass’s blog. EPA cancelling toxic pesticide, endosulfan. June 9, 2010.

[vii] Bradman A, Harnly ME, Draper W, Seidel S, Teran S, Wakeham D, Neutra R  1997. Pesticide exposure to children from California’s Central Valley: results of a pilot study. J. Expo. Anal. Environ. Epidemiol. 7, 217-234

See also Fenske et al, EHP 2002

[viii] EPA-HQ-OPP-2009-0889-0002

[ix] See the EPA website on illegal pesticide products available for sale in the U.S.:

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Peter CrownfieldJan 18 2011 06:01 AM

Add to your list the failure to test pesticides and other substances in combination, the way they are found in the real world.

Although most pesticides are harmful to human health on their own, even trace levels turn out to be harmful when part of the chemical 'cocktail' to which we are all exposed.

hamishdadJan 18 2011 08:46 AM

When it comes to pesticide regulation, commerce almost always trumps safety concerns. If the EPA finds an exposure scenario that poses a risk to toddlers, instead of taking steps to eliminate that scenario, the EPA will "refine" its default assumptions and endpoints - often based on data provided by the regulated industry - so that it's no longer a concern. Even in those rare instances when the EPA is successful in convincing a manufacturer to discontinue a dangerous pesticide product, it allows the manufacturer and retailers to distribute and sell the product until existing stocks are exhausted, which could take years.

Jon EntineJan 24 2011 02:01 PM

It's always disconcerting to read analyses that are ideological but uses the jargon of science to convey the misleading sense that they're "objective." Sass's biggest distortion is mis-framing the research divide over pesticides as "industry science versus academic science." She's created a strawman.

In fact, the divide is between established scientific bodies, such as the EPA and the World Health Organization (whose laser focus is to evaluate the health risk to humans) and who depend on large-scale studies to make such determinations, and university researchers, who have a far narrower, academic mission. As Dr. Lynn Goldman, the Dean of GWU's School of Public Health--who is very liberal but balanced on this issue--has repeatedly noted, the key differences between the approaches is studies by university scientists are hypothesis-driven: they are usually small, asking targeted but limited questions designed to challenge existing health paradigms. Free of regulatory responsibilities, and often aided by overt advocates, such as Sass, they regularly trumpet their findings to a sympathetic media that does not understand how to scientifically evaluated health risks.

In contrast, the majority of the state-of the-art larger studies—often funded by industry at the behest and oversight of regulators--follow GLP (which despite Sass's mis-framing remains the gold standard in the science community). It's what the EPA, FDA and other regulators rely upon--studies that look at human risk.

Sass uses a classic tactic--absent any specific evidence of corrupted industry studies on pesticides, she employs an ad hominem attack. Notably, she does not address examples of manipulated data among some key academics doing pesticide research--such as Berkeley's Tyrone Hayes. Hayes has refused to submit his raw data for EPA review, no scientists have been able to replicate his controversial key conclusions, and his work has been received with skepticism by mainstream scientists and universally rejected by regulators around the world--yet Sass, in particular, cites him glowingly and relentlessly. That's not science; that's advocacy.

In essence, there is often a clash of cultures between academic researchers, who are testing novel and unproven hypotheses about the potential hormonal and epigenetic (i.e. non-genetic factors that cause an organism’s genes to behave or express themselves differently) and regulatory scientists, who must weigh a range of risks and unintended consequences before enacting or changing regulations.

In other words: read Sass's "analyses," here and elsewhere, with extreme caution. Check out what science regulators--all of whom are "leftist'' say. Sass is way out of the science mainstream. There are advocacy groups, including the Environmental Defense Fund, that offer far more thoughtful and less ideological analyses of complex issues involving pesticides and chemicals--and EDF and others honestly disclose their perspectives, unlike the NRDC, which tries to pretend that it's purely science driven.

If you're interested in the politics of the debate over pesticides, I suggest you check out my new edited volume, "Crop Chemophobia":

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