Chlorpyrifos. You’ve probably never heard of it, but you’ve almost certainly eaten food that’s come into contact with it. Curious?  It’s an insecticide, fungicide, and miticide produced by Dow AgroSciences, and it’s applied widely to fields in the United States.  In addition to ridding fields from pests, the chemical is also a neurotoxin, affecting an enzyme called cholinesterase, which is central to the function of the central nervous system. The chemical also has adverse effects on the cardiovascular and respiratory systems.

Despite the potential detrimental effects on human health that go along with the use of Chlorpyrifos, the Environmental Protection Agency (EPA), at Scott Pruitt’s ruling, has denied a petition by the Natural Resources Defense Council and Pesticide Action Network North America. The petition proposed a ban on the pesticide, given the risks that its use poses on field workers, consumers, and those who live near application areas. This may seem like a simple ruling, but there is a lot of work, research, and time that goes into decisions of this nature--work, research, and time that Mr. Pruitt seems to have ignored in his decision. Grasping the gravity and indiscretion of Pruitt’s decision requires an understanding of processes by which the EPA develops risk assessments for pesticides.

In 1975, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) established the FIFRA Scientific Advisory Panel (SAP). The SAP is comprised of a board of  “biologists, statisticians, toxicologists, and other experts who provide independent scientific advice to the EPA on a wide-range of health and safety issues related to pesticides.” While SAP members do serve as government employees, they are nominated by the National Institutes of Health and the National Science Foundation and are generally sourced from field leaders whose careers lie outside of executive agencies. For example, five of the six current members of the SAP are university professors.  Ultimately, the purpose of the FIFRA SAP is to provide unbiased scientific analysis, specifically risk assessment analysis, for the effects of chemical use in the United States. These risk analyses are used to determine what chemical levels are safe, for both human and environmental health, on a substance-by-substance basis.

The risk analysis process is both thorough and periodical, and the history of chlorpyrifos regulation spans decades. In 2000, the EPA restricted the home-use of products containing chlorpyrifos, banned the product’s use on tomatoes, and restricted its use on apples and grapes. In 2002, the use of the pesticides was further restricted in instances of use on citrus, tree nuts, and several other crops. The EPA ran a preliminary human health risk assessment of chlorpyrifos in 2011. In 2012, application rates were lowered and “no-spray” zones were created in recreational and residential areas.  In 2014, the EPA released a revised risk assessment, updating the information provided in the 2011 assessment. With each subsequent assessment, new information is taken into account, and approaches become more finessed.  For example, the 2014 assessment incorporated new scientific information that was not available at the time of the 2011 assessment, and when reevaluating the safety of chlorpyrifos in 2016, the SAP used a new, enhanced mathematical model  that took into account the varying effects that chlorpyrifos may have on the basis of factors such as age and genetics. This type of model allows for a more nuanced understanding of how a chemical might affect different demographics.

This mathematical model uses data from a myriad of independent scientific studies. The assessment includes an investigation of chemical effects in accordance with many parameters, including but not limited to the following:

• chemical composition
• application methods and rates
• residue levels on food
• transferable residues on turf in residential areas
• spray drift on agricultural fields
• occupational risks

The full report, released in November of 2016, can be viewed in federal docket EPA-HQ-OPP-2015-0653.

The risk assessment methodology not only covers a breadth of areas-- it is also quite thorough in each of these areas. Indeed, the federal docket entitled Reader’s Guide to Chlorpyrifos Notice of Data Availability, which contains information regarding how to access the data used in the risk assessment, states that the volume of files exceeds what can be put into a federal docket and provides a phone number and email for requesting access to the data.   

In other words, our scientific understanding of the effects of chlorpyrifos is overwhelming. This is not, however, how Scott Pruitt sees it. On March 29th, Pruitt denied a petition to ban the herbicide, and in an official statement, said that “by reversing the previous Administration’s steps to ban one of the most widely used pesticides in the world, we are returning to using sound science in decision-making – rather than predetermined results.” This statement is, on all accounts, blatantly false. It is true that there remains a level of uncertainty regarding the exact effects of chlorpyrifos, as there is with any scientific matter. However, I argue that this uncertainty should result in a more conservative and cautious approach to regulation-- it should not result in deregulation. Additionally, it is clear that the FIFRA SAP does not base its recommendation on predetermined results. Rather, it seems that Pruitt is basing his claims on the predetermined economic motives. Yet, it is very difficult to determine the exact economic effects of reduced or eliminated pesticide use on crop yields. Studies investigating these effects have produced estimates that have varied wildly. So, when considering the regulation of a chemical, it seems empirically unsound to rely heavily on economic claims that are not entirely agreed upon.

Of course, evidence or not, the decision has already been made. Sheryl Kunickis, newly appointed director of the Office of Pest Management and Policy at the US Department of Agriculture, stated that the denial of the petition is “great news for consumers, who will continue to have access to a full range of both domestic and imported fruits and vegetables.” To what extent is this true? Time alone will tell.