Center for Biological Diversity

For Immediate Release, April 20, 2021


Lori Ann Burd, (971) 717-6405,

Federal Analysis Finds Insecticide Malathion Imperils Continued Existence of 78 Endangered Plants, Animals

Using Trump-era Guidelines, ‘Jeopardy’ Calls Reduced from 1,284 to 78 Species

WASHINGTON— A U.S. Fish and Wildlife Service analysis released today has found that the commonly used insecticide malathion jeopardizes the continued existence of 78 endangered plants and animals.

The analysis is one of most extreme findings of harm ever published by the Service. Yet it represents a dramatic departure from the findings of an Obama administration analysis scrapped by the Trump administration that found malathion jeopardized 1,284 endangered plants and animals.

Today’s analysis deploys former Interior Secretary David Bernhardt’s methods to discount the harms of the pesticide by unlawfully relying on incomplete, unreliable estimates of its use rather than looking more broadly at the overall effects of its registration by the Environmental Protection Agency, as required by the Endangered Species Act.

Malathion is used on a wide variety of crops, including corn, wheat, vegetables and fruits and is sprayed for mosquito control.

“This deep bow to the Trump administration’s reckless disregard for science imperils the survival of over a thousand of our most endangered plants and animals,” said Lori Ann Burd, environmental health director at the Center for Biological Diversity. “The Fish and Wildlife Service’s disappointing decision to embrace the junk science policies of the previous administration risks the extinction of animals like rusty patched bumblebees, Indiana bats and whooping cranes to prop up pesticide company profits.”

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 were 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 people.

The analysis raises questions about the pesticide’s potential harm to pollinators and of the consequences to endangered plants. Plants make up more than half of all endangered species, and the overwhelming majority of endangered plants are dependent on insect pollinators to reproduce.

Because the EPA allows the use of malathion virtually anywhere, the harm to plants and animals is widespread.

“We need to impose commonsense restrictions on pesticide use if we want to dodge mass extinctions in this country, and this is our moment to do just that for malathion,” said Burd. “But that won’t happen unless the Biden administration grows a spine and stands up to the powerful pesticide industry. And this analysis suggests that they’d rather not.”


As part of a legal settlement, the U.S. Fish and Wildlife Service was supposed 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.

In January 2017 the EPA completed its part of that process when it issued its biological evaluation determining that 97 percent of federally protected species are likely harmed by malathion, which also has been found by the World Health Organization to be “probably carcinogenic to humans.”

Following the EPA’s announcement, officials at Dow AgroSciences, which produces malathion, 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 rigorous scientific review.

Following this briefing, top officials at the 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 the insecticide’s use in areas where species are imperiled by it.

In May of 2018 the Center once again sued the EPA and Service for failing to comply with their duty to study the impacts of malathion, as required by the Endangered Species Act. Under continued pressure to comply with the law the Fish and Wildlife Service released today’s assessment.

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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