EPA is taking the next step in its regulatory review of atrazine, simazine and propazine, three widely-used herbicides used to control a variety of grasses and broadleaf weeds. Atrazine is used on about 75 million acres of agricultural crop land every year and is especially effective, affordable, and well-studied.

In September 2020, EPA announced its interim registration review decisions for atrazine, simazine and propazine (collectively known as the triazines), finalizing measures to protect human health, mitigate potential ecological risks while providing America’s farmers with valuable tools they have come to rely upon.

Today, EPA is releasing its draft biological evaluations (BEs) for triazines for public review and comment. Biological evaluations are the beginning of EPA’s Endangered Species Act consultation review process for pesticides where the agency determines if an endangered or threatened species or critical habitat could be affected by the use of a certain pesticide.

EPA will accept public comments on the draft evaluations until Jan. 5, 2021. After carefully considering the public comments received and any additional data received, the agency will finalize the BEs. If EPA determines a pesticide may affect a listed species or its critical habitat, the agency will consult with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service (the Services) as appropriate. The Services will then issue a biological opinion to determine if the population of a species would be adversely impacted and, if so, propose ways to reduce risks. It is the goal of EPA to ensure that pesticides can continue to be used safely with minimal impacts to threatened and endangered species.

This is the second group of pesticides, and the first herbicides, where the agency used its March 2020 Revised Method for National Level Listed Species Biological Evaluations of Conventional Pesticides to assess potential impacts that these herbicides may have on threatened and endangered species and their critical habitats. As such, EPA used advanced exposure modeling techniques to estimate exposures to plants in various environments such as wetlands.

The biological evaluations make effects determinations for 1,795 listed species and 792 designated critical habitats when these pesticides are used according to product labels. This includes no effect (NE), not likely to adversely affect (NLAA), and likely to adversely affect (LAA) determinations. A summary of LAA determinations for atrazine, simazine, and propazine is below:

- Atrazine is likely to adversely affect 54 percent of all species and 40 percent of critical habitats;

- Propazine is likely to adversely affect 4 percent of all species and 2 percent of critical habitats;

- Simazine is likely to adversely affect approximately 53 percent of species and 40 percent of critical habitats.