Center for Biological Diversity

For Immediate Release, March 8, 2022


Lori Ann Burd, (971) 717-6405,

U.S. Fish and Wildlife Reverses Course, Asserts That Neurotoxic Pesticide Malathion Will Not Put a Single Protected Species At Risk of Extinction

Agency Adopts Debunked Trump-Era Methods to Discard Its Own Science Saying Malathion Likely Jeopardizes Nearly 1,300 Protected Species

WASHINGTON— The U.S. Fish and Wildlife Service announced today that the widely used insecticide malathion does not pose an extinction risk to a single protected animal or plant and refused to implement any immediate, enforceable measures to protect species from the chemical poison.

Today’s final biological opinion, which relies on scientifically unfounded assessment methods imposed during the Trump administration, stands in sharp contrast to the agency’s 2017 conclusion that 1,284 species would likely be jeopardized by malathion.

The opinion even backtracked from a draft biological opinion released by the Service just last year, which also used the debunked Trump-era methodology promoted by the pesticide industry to determine that 78 endangered plant and animal species were jeopardized by the pesticide.

“The Biden administration has squandered a historic opportunity to rein in the dangerous use of one of the world’s worst neurotoxic pesticides,” said Lori Ann Burd, environmental health director at the Center for Biological Diversity. “By ignoring the best available science and choosing to rely on promises of good behavior by the pesticide makers rather than real on-the-ground conservation measures, the Biden administration is condemning wildlife to extinction with a wink and a nod. This decision to cave to powerful special interest groups will do far-reaching harm to our most endangered wildlife.”

One week ago the National Marine Fisheries Service, a sister agency to the U.S. Fish and Wildlife Service, released an updated biological opinion that determined malathion and two other toxic organophosphate pesticides are causing jeopardy to virtually every endangered U.S. salmon, sturgeon and steelhead species, as well as to Puget Sound orcas.

The Fisheries Service opinion debunks the Trump methodology that based harm analyses on historic use data known to be incomplete and unreliable. Specifically, the Fisheries Service found that: “Given the degree of uncertainty and speculation associated with these factors, and usage information generally, we determined that in most cases we cannot rely on them to construct assumptions about the exposure potential and at the same time ensure listed species will not be jeopardized.”

Yet the Fish and Wildlife Service continued to heavily rely on the same historic use data in its analyses to reach conclusions that the pesticide would not harm endangered species into the future.

The widely disparate findings by the two agencies were highlighted in harm assessments for bull trout and salmon, biologically similar species that share habitat in the Pacific Northwest. The Fish and Wildlife Service has determined that malathion won’t harm bull trout in Pacific Northwest streams; meanwhile the Fisheries Service has concluded that the use of the very same chemical in the very same streams is pushing every Pacific salmon to extinction.

“One’s based on sound science, and one’s based on industry-driven politics,” said Burd. “The Fisheries Service is bravely taking a stand to prevent extinctions while the Fish and Wildlife is continuing to cower to an anti-science, anti-endangered species agenda.”

Today’s final biological opinion restricts some uses of malathion, in theory, but contains loopholes that render important restrictions meaningless in the real world. For example, mosquito spraying with malathion is restricted “where feasible.” But what renders the restrictions unfeasible is undefined, allowing continued spraying of the pesticide.

This analysis is the first nationwide biological opinion completed by the Fish and Wildlife Service for any pesticide. But it embraced industry friendly methodologies for species’ harm assessments that were ordered after a direct intervention by President Trump’s secretary of the Interior, David Bernhardt.

“Why the Biden administration is hiding behind David Bernhardt’s twisted legal thinking so that it can ignore the heartbreaking extinction crisis is beyond dumbfounding,” said Burd. “President Biden’s conservation promises are meaningless if this administration doesn’t even have the backbone to stand up to the corporations poisoning our planet and our children.”

Around 1 million pounds of malathion are used in the United States each year. The insecticide is a neurotoxin that is part of the dangerous class of old pesticides called organophosphates. Organophosphates have been used as nerve agents in chemical warfare and have been linked to Gulf War syndrome, which causes fatigue, headaches, skin problems and breathing disorders in humans.


In January 2017 the EPA completed its biological evaluation on malathion, determining that 97% of federally protected species are likely harmed by malathion. Following this announcement, Dow AgroSciences officials asked the Trump administration to suspend the assessments.

In May 2017 the Fish and Wildlife Service announced that after nearly four years of work its draft biological opinion assessing the pesticide’s harms was nearly complete and would be ready for public comment within months. As Fish and Wildlife Service career staffers were preparing to make the biological opinion available for public comment, they briefed Trump's political appointees, including then-acting Interior Secretary Bernhardt, on the results of the agency's nearly four years of rigorous scientific review.

Following this briefing, top officials at Trump’s Department of the Interior, including Bernhardt, acted to indefinitely suspend the release of the Service’s assessment. The Trump administration’s unprecedented efforts to undermine those findings were highlighted in a New York Times investigation.

A document obtained by the Center for Biological Diversity through the Freedom of Information Act revealed the assessments were suspended after the top political appointees were briefed on the fact that the Service’s analysis had determined that malathion jeopardized the continued existence of 1,284 protected species.

In the intervening years, the findings have prompted no action by the EPA to limit malathion’s use in areas where species are imperiled by it.

As part of a legal agreement, the Fish and Wildlife Service was required to issue a biological opinion by the end of 2017 identifying ways to safeguard endangered species from malathion, as well as two other organophosphate insecticides, chlorpyrifos and diazinon, as required by the Endangered Species Act. The Trump administration refused to abide by the legal agreement.

In May of 2018 the Center again sued the EPA and Service for failing to comply with its duty to study the impacts of malathion, prompting the agency to release today’s assessment.

Last month the Center sued the Fish and Wildlife Service for failing to complete endangered species consultations on the pesticides chlorpyrifos and diazinon.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.7 million members and online activists dedicated to the protection of endangered species and wild places.

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