Judge orders wildlife service to do more to protect imperiled species from pesticides

A federal judge ruled late Wednesday that the US Fish and Wildlife Service (FWS) must finish assessing the impact of five pesticides on endangered and threatened species, and that the agency had violated federal law with its “unreasonable” delay in completing the required analyses.

The five chemicals include the weed killers atrazine and simazine, and the insecticides ​chlorpyrifos, diazinon, and carbaryl.

The ruling ought to force the Trump administration to “protect imperiled wildlife from harms caused by pesticides,” said Jonathan Evans, environmental health legal director at the Center for Biological Diversity, which brought the suit.

“We’re glad the court found the federal government still has to follow the law,” including the Endangered Species Act (ESA), to protect imperiled wildlife, Evans said.

The Environmental Protection Agency (EPA) has completed initial evaluations for all the chemicals, finding that they present serious risks to threatened and endangered species. For example, the EPA concluded that chlorpyrifos  is “likely to adversely affect” 1,778 threatened or endangered plants and animals, a whopping 97% of all protected wildlife.

The EPA likewise reported that diazinon is likely to harm 78% of these species; carbaryl, 91%; and atrazine and simazine, 56% and 55%, respectively.

The ESA compels the FWS to craft “biological opinions” for most pesticides in a reasonable time frame, in part by consulting with the EPA, to determining the degree to which each substance jeopardizes the continued survival of protected species, the court ruling explains.

The FWS has already completed a draft biological opinion for carbaryl, and the judge ordered the agency to finalize it by March 31. The government analysis found the chemical “is likely to jeopardize the continued existence of 78 proposed or listed species,” including species as diverse as the yellow-shoulder blackbird, Houston toad, and Salt Creek tiger beetle.

A sixth chemical that was originally part of the lawsuit, methomyl, was dropped when the FWS published a biological opinion on the chemical on December 30, 2024.

That report found that the continued use of methomyl, a highly toxic insecticide, is likely to jeopardize the survival of 82 listed species, including the Fender’s blue butterfly, Hine’s emerald dragonfly, Indiana bat, red wolf, and more. It also recommended a series of mitigation measures meant to avoid this harm, which includes ongoing changes to the label and mapping efforts of areas where it should not be used.

The decision from US District Judge John Hinderaker, a 2020 Trump appointee, gives the FWS a March 31, 2026 deadline for atrazine and simazine. And the agency must complete its work on chlorpyrifos and diazinon by September 30, 2028.

The judge noted that the government had been or “should have been” aware of the need for the formal consultations on each of the pesticides for more than a decade but had failed to act in a timely manner.

The ruling came the same day that EPA administrator Lee Zeldin announced the agency would repeal dozens of the country’s most important environmental regulations, calling it in a statement “the greatest day of deregulation our nation has seen.”

Former EPA administrator Gina McCarthy told the New York Times it was “the most disastrous day in EPA history. Rolling these rules back is not just a disgrace, it’s a threat to all of us.”

Though Trump has shown hostility to environmental laws, such rules cannot just be ignored, Evans said, as this case illustrates. “The statutes trump Trump,” he said.

(Featured image by Getty Images for Unsplash+.)