Fish and Wildlife Service says atrazine unlikely to jeopardize endangered species

The U.S. Fish and Wildlife Service has concluded that atrazine, one of the nation’s most widely used agricultural herbicides, is not likely to jeopardize endangered species or destroy critical habitat when conservation measures are incorporated into its label requirements.

The decision is part of the Environmental Protection Agency’s ongoing registration review of atrazine under the Federal Insecticide, Fungicide, and Rodenticide Act, which requires pesticides to be reevaluated every 15 years.

FWS’s biological opinion evaluated potential impacts on 543 listed species and 203 designated or proposed critical habitats. “After incorporating conservation measures on the atrazine label, we found that the proposed registration … is not likely to jeopardize the continued existence of the species in this consultation,” the agency said.

The opinion acknowledges that some individual species or habitat elements could experience adverse effects from exposure but concludes those impacts would not rise “to a level that would appreciably diminish their value … as a whole.”

The findings differ from EPA biological evaluations released in 2021, which concluded atrazine was likely to adversely affect more than 1,000 protected species.

EPA completed an interim registration decision for atrazine in September 2020, but lawsuits from environmental and conservation groups led to a partial remand, prompting additional consultation between EPA and FWS on the herbicide’s potential effects on threatened and endangered species.

Syngenta, atrazine’s primary manufacturer, said the pesticide approval process already includes stringent safeguards. According to a company spokesperson, EPA routinely applies multiple safety margins — including a default 10-fold safety factor — when establishing pesticide residue limits, resulting in standards the company said are often set far below levels already deemed safe.

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Atrazine is a systemic herbicide used to selectively control annual grasses and broadleaf weeds before they emerge. It is registered for use on a range of agricultural crops, with the highest application rates in field corn, sweet corn, sorghum and sugarcane. A Syngenta spokesperson described atrazine as a “widely used and extremely important weed control tool” for U.S. farmers, saying it plays a key role in managing resistant weeds, supporting conservation tillage and protecting crop yields and the nation’s food supply. “Atrazine not only boosts productivity but also substantially reduces U.S. agriculture’s environmental footprint,” the spokesperson said.

Because atrazine is classified as a restricted-use pesticide, only certified applicators may purchase and apply it, and farmers must follow strict label requirements designed to minimize environmental and aquatic impacts.

According to the most recent usage data, farmers apply an average of 72 million pounds of atrazine annually across roughly 75 million acres of cropland.

Environmental groups maintain that atrazine remains one of the most widespread pesticide contaminants in U.S. waterways. Advocacy organizations, including the Center for Biological Diversity and the Center for Food Safety, have repeatedly challenged atrazine approvals in court and petitioned the Trump administration to ban the herbicide. Syngenta argues that decades of scientific review and repeated federal evaluations support atrazine’s continued use when label restrictions are followed.

Environmental groups have also voiced disappointment in the Make America Healthy Again commission spearheaded by Robert F. Kennedy Jr., which initially issued a report suggesting links between farm chemicals, including atrazine, and adverse health outcomes. After objections from agricultural groups, later reports did not include recommendations for specific chemical restrictions.

“The Trump administration has once again done the pesticide industry’s bidding,” said Nathan Donley, environmental health science director at the Center for Biological Diversity.