U.S. EPA releases final biological evaluations for glyphosate, atrazine, and simazine

After consideration of public comments, EPA has finalized its biological evaluations (BEs) for glyphosate, atrazine, and simazine, three herbicides that are used to control a variety of grasses and broadleaf weeds. EPA has also released a summary document of comments received on the draft BEs and EPA’s responses. A BE is a document that contains EPA’s analysis of the potential effects of a pesticide on federally threatened or endangered species and their designated critical habitat. It includes any conclusions that the pesticide may affect, and is likely to adversely affect, any of these species or habitats.  

EPA evaluated glyphosate, atrazine, and simazine to determine whether they may affect one or more species listed under the Endangered Species Act (ESA) or their designated critical habitats. The BEs find that all of these chemicals may affect, and are likely to adversely affect, certain listed species or their designated critical habitats. These evaluations encompass all registered uses and approved product labels for pesticide products containing these three herbicides.  

The “likely to adversely affect” (LAA) determination means that EPA reasonably expects that at least one individual animal or plant, among a variety of listed species, may be exposed to the pesticide at a sufficient level to have an effect, which will be adverse. The LAA threshold for a BE is very sensitive because the likely “take” of even one individual of a species, which includes unintentional harm or death, triggers an LAA determination. This is the case even if a species is almost recovered to a point where it no longer needs to be listed. As a result, there is a high number of  "may affect” and LAA determinations in these BEs. An LAA determination, however, does not necessarily mean that a pesticide is putting a species in jeopardy. Jeopardy determinations will be made by the U.S. Fish and Wildlife Service and the National Marine Fisheries Service (collectively “the Services”) in the course of formal consultation that evaluates any effects of the pesticides on entire species. 

In early 2021, atrazine and simazine registrants requested to voluntarily prohibit use of atrazine and simazine in Hawaii, Alaska, and the U.S. territories and to delete certain uses from their product registrations. Registrants took this action to reduce the potential overlap between where these pesticides can be used and listed species and their critical habitats. Atrazine uses were cancelled for roadsides, Conservation Reserve Program land, conifers, including Christmas tree plantings, timber and forestry, and miscanthus and other perennial bioenergy crops. Simazine uses were cancelled for shelterbelts and forestry (except for Christmas tree plantings). EPA issued a notice of receipt of the use cancellation requests on June 23, 2021, and a final notice to terminate certain uses and cancel certain products containing atrazine and simazine on November 1, 2021. In reducing potential overlap, the geographic use prohibitions and voluntary use cancellations effectively reduced the number of LAA determinations in the final BEs for atrazine and simazine.  

In January 2021, the only propazine registrant requested to voluntarily cancel its remaining product registrations. On June 8, 2021, EPA issued a final cancellation order for propazine, which terminated the last propazine products registered in the United States, therefore EPA did not complete a BE for propazine.

The Services will use the information in EPA’s final BEs for these three herbicides to develop their biological opinions (BiOps). The Services may also conduct additional analyses and use additional information that EPA and the applicants provide to support their BiOps. In a BiOp, the Services document their determination of whether a pesticide is likely to jeopardize the continued existence of the species and whether there will be adverse modification to its designated critical habitat. If jeopardy or adverse modification is determined, the Services, with input from EPA and the registrants, will propose additional protections. 

Read the final biological evaluations for glyphosate, atrazine, and simazine on EPA's website.