Chlorpyrifos is an insecticide that has been used since 1965 to protect crop fields (e.g., corn, soybeans, fruit trees) and used to protect golf courses and greenhouses. Chlorpyrifos insecticide products are sold as liquids, granules, powders. The EPA recommends that workers using a chlorpyrifos product wear coveralls, gloves, and a respirator to protect themselves, and restrict entry into treated areas for up to five days. Chlorpyrifos is not as well-known as the herbicide glyphosate. For now, there has not been a bellwether verdict against a chlorpyrifos manufacturer like there has been against a glyphosate manufacturer. However, the glyphosate verdict came after the World Health Organization (WHO) classified glyphosate (Group 2A), and it is currently evaluating chlorpyrifos. While chlorpyrifos has been beneficial to farmers and other agricultural users to protect their crops and grounds from insects and other pests, it is a neurotoxin that can also cause nausea, dizziness, confusion, respiratory paralysis and death, and research has found exposure risks to unborn children. In addition, chlorpyrifos went largely unregulated for decades as a popular agricultural and home product. Chlorpyrifos shows all of the signs of being the next high-profile toxic tort litigation involving an agricultural product.

The EPA did not begin to regulate the use of chlorpyrifos until 2000, when manufactures voluntarily agreed to stop marketing it for most in-home uses.  Between 2000 and 2016, the EPA decreased spray-uses and instituted “buffer zones” around areas where chlorpyrifos was used. In 2016, EPA released an updated risk assessment that included studies on exposures through food, water, and inhalation as well as studies on infants, children, and women of child-bearing age. However, the EPA resisted calls for an outright ban on chlorpyrifos. A court battle ensued between 2017 and 2019 to try to force the EPA to ban chlorpyrifos; however, the Ninth Circuit Court of Appeals ultimately vacated an earlier ruling that would have required EPA to completely ban chlorpyrifos. In response to the lawsuit against the EPA, some states (California, New York, and Hawaii) have simply taken it upon themselves to ban chlorpyrifos after unsuccessfully suing EPA to implement a full federal ban on chlorpyrifos.

In September 2020, the EPA released a draft Ecological Risk assessment and Revised Human Health Risk Assessment for chlorpyrifos. This risk assessment walks back many of the findings that were in the EPA’s 2016 risk assessment. The EPA no longer relies on certain studies that show health hazards associated with chlorpyrifos due to the lack of having researchers’ raw data, which in one instance the raw data was withheld by researchers due to concerns over disclosing potential confidential identifying information. Furthermore, the EPA is now relying upon a study commissioned by a major manufacturer of chlorpyrifos that shows that there are health hazards to pregnant women and unborn children but only in very specific circumstances.

Legitimate questions persist given that the EPA seemingly reversed its stance on regulating chlorpyrifos. For instance, did EPA’s reversal regarding chlorpyrifos inadvertently impugn its own reasoning that glyphosate poses no hazard? In addition, how will the WHO classify chlorpyrifos after it completes its evaluation of it in drinking water? Who would be exposed to litigation from such a decision by the WHO?  Notwithstanding, the EPA is still a long way from publishing a final assessment (it has a statutory deadline of October 1, 2022), which means there will be many more comment periods and a presidential election prior to the release of the final assessment. Nevertheless, those who closely follows the glyphosate litigation are now turning their attention to the regulatory bodies’ actions with respect to chlorpyrifos, especially plaintiffs’ counsel.