EPA Leadership Interfered with Scientific Studies on the Risks of Hazardous Herbicide, Dicamba

Published Jun 29, 2022

What Happened: According to the Environmental Protection Agency’s (EPA) inspector general, senior EPA officials inappropriately interfered with the work of federal scientists. The senior officials omitted scientific evidence related to the decisions to approve three weed-killing products using the active ingredient, dicamba.

Why It Matters: EPA is required by law to use the best available science to determine the dangers of pesticides. When political officials edit out scientific information as the agency weighs whether to allow the sale and use of pesticide products, it imperils the agricultural economy and public health. Senior EPA leadership interfered with scientific studies evaluating the risks of dicamba herbicides to human health and the environment, violated principles of scientific integrity, and undermined the scientific processes meant to keep the public and environment safe from harmful pesticides.

Senior officials at the Environmental Protection Agency (EPA) interfered with the work of EPA scientists during a 2018 scientific assessment of dicamba, a widely used herbicide, by omitting key scientific evidence from risk evaluations. As a result, the EPA extended the use of three dicamba products – XtendiMax, Engenia, and FeXapan – despite the science suggesting that dicamba is hazardous to crops and other plants, due to its ability to turn into a gas resulting in “pesticide drift” onto neighboring fields, and is a cancer-causing chemical in humans.

In May 2021, a watchdog report from the EPA’s inspector general documented how the agency bypassed routine and science-based procedures when conducting risk assessments of dicamba products. The report stated that “past senior leadership consciously chose to advance a policy outcome in a manner inconsistent with the [EPA’s] Scientific Integrity Policy.” It further described how EPA leadership instructed scientists to forego required peer reviews, based decisions on reports with insufficient industry-provided data that under-reported dicamba damage, and disregarded key studies with robust data on risks and adverse effects. EPA scientists reported to the Office of Inspector General that “the internal review process would not have made a difference [due to] significant involvement of senior management.” This weakened scientific assessment allowed the EPA to extend the registration of these three dicamba herbicides up until 2025 with little change to require strengthened protections for farmworkers or the general public.

This decision by the EPA goes against a federal court order issued in June 2020 by the U.S. Court of Appeals for the Ninth Circuit. The court stated that the EPA “substantially understated risks [of the dicamba products]” and that the agency “failed entirely to acknowledge other risks,” which the court determined was a violation of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). This is not the first account of the Trump administration EPA prioritizing politics over science, as a similar incident occurred in February 2020 when EPA officials interfered and downgraded the cancer-rating of a highly toxic pesticide known as Telone.

Independent science should serve as the basis in the decision-making process for determining the risks associated with pesticides, especially when it comes to deciding how the sale and use of these hazardous chemicals should be regulated. Failing to do so not only ignores EPA’s mandate to protect human health and the environment, but could constitute a violation of the EPA’s Scientific Integrity Policy, which states that the agency has a duty to ensure adherence to scientific integrity. By failing to follow the science, the EPA has endangered the lives of frontline farmworkers and neighboring communities that are exposed to dicamba pollution daily. Furthermore, the agency’s actions could result in continuous damage to crops that farming communities’ livelihoods depend on, thereby allowing industry to profit while continuing the cycles of environmental injustice that disproportionately harm the health and well-being of marginalized communities.