EPA’s Biological Evaluation for ESA Threatens Atrazine’s Future

On Nov. 5, 2020, EPA published its draft biological evaluation (BE) of atrazine. A comment period ended on Feb. 19, 2021. Many growers and farm organizations submitted comments to the docket.

The Biological Evaluation is an assessment of risks to listed endangered or threatened species from labeled uses of atrazine. It also includes a draft ecological effects assessment and determines the toxicological endpoints—the range of acceptable amounts of atrazine in the environment—to be used in EPA’s ecological effects determinations.

EPA inexplicably found that atrazine is likely to adversely affect nearly all species and critical habitats in the continental United States, including some that are already extinct. This could affect the future availability of atrazine in the marketplace.


EPA failed to fulfill commitments to incorporate the best available science and adopt a quantitative weight of the evidence approach to endpoint determination. A submitted analysis that included the most up-to-date studies on ecological toxicity and exposure to help in this effort was ignored.

EPA has not responded to all public comments, including grower concerns, as required by law. The agency had earlier made a commitment to growers to address in the BE issues identified by outstanding comments on previous registration review decisions — but that has not happened. These included: concerns about methodology; use of poor data and low quality scientific studies; failure to use a rigorous quantitative weight of the evidence approach; and the establishment of too-conservative ecological endpoints. These same issues have been repeated and compounded in the BE and if not fixed, could affect the future availability of atrazine in the marketplace.

EPA is transferring to the U.S. Fish and Wildlife and National Marine Fisheries Service (the Services) its responsibility to make accurate and realistic assessments of potential impacts of atrazine to listed species.

Other flaws include counting as affected by atrazine a number of extinct species that have been recommended by the Services for delisting due to extinction, such as the southern acornshell, which was last collected in 1973, and the upland combshell, last collected in 1986.


  • If the current BE is allowed to stand unchanged, poor quality science will have inaccurately depicted atrazine as a threat to listed species. This false reputation could restrict the use and even availability of a crucial crop protection product that is effective and low-impact on the environment.
  • Banning atrazine is a top priority of well-funded activists. They believe if they can ban a product that has been proven safe for over 60 years, they can ban any crop protection tool.
  • We can’t allow that to happen. We must keep the pressure on EPA to get the science right.