EPA Finds Atrazine Likely Harming Most Species of Plants, Animals in U.S.

For Immediate Release

EPA Finds Atrazine Likely Harming Most Species of Plants, Animals in U.S.

PORTLAND, Ore. - The amount of the herbicide atrazine that’s released into the environment in the United States is likely harming most species of plants and animals, including mammals, birds, amphibians and reptiles, according to a preliminary risk assessment by the Environmental Protection Agency. Atrazine is well known as a hormone disruptor that has been linked to birth defects and cancer in humans and contamination of ground-, surface- and drinking-water supplies.

The second-most widely used pesticide in the United States, already banned in Europe, was found to cause reproductive harm to mammals and birds in real-world scenarios, with EPA “levels of concern” surpassed nearly 200-fold, according to the new EPA assessment. Also, water monitoring has shown atrazine to be present at levels much higher than are needed to kill an amphibian.

The assessment was posted on the EPA’s website on Friday but has since been removed. A copy is available here.  

“The EPA has determined that the amount of atrazine that’s in streams and rivers right now is enough to kill frogs and other imperiled wildlife,” said Nathan Donley, a scientist with the Center for Biological Diversity. “How many animals have to die before we do what Europe did 12 years ago and ban atrazine?” 

Amphibians are particularly vulnerable to pesticide impacts because they live in waterways where their permeable skins absorb contaminants from agricultural runoff. Dr. Tyrone Hayes, at the University of California, has shown that atrazine chemically castrates and feminizes male frogs at concentrations lower than the level allowed in drinking water by the EPA. Late last year a group of prominent scientists criticized California’s proposed “safe harbor level” for atrazine because it didn’t protect public health and the environment.

“When the amount of atrazine allowed in our drinking water is high enough to turn a male tadpole into a female frog, then our regulatory system has failed us,” said Donley. “We’ve reached a point with atrazine where more scientific analysis is just unnecessary — atrazine needs to be banned now.”

Currently 70 million pounds of atrazine are used in the United States each year, contaminating ground, surface and drinking water.

These findings come as the EPA is in the process of “registration review” of atrazine, a process designed to determine whether the chemical can safely be used in light of new scientific study. The assessment will inform EPA’s decision on whether to allow atrazine to be used for the next 15 years. The last time the agency fully analyzed the threats posed by atrazine was in 2003; no new registration decision has been made so far.  

In a historic settlement reached with the Center, the U.S. Fish and Wildlife Service and EPA will analyze the impacts of atrazine on more than 1,500 endangered U.S. plants and animals. The agreement ensures that conservation measures will be put in place for atrazine in the future.


At the Center for Biological Diversity, we believe that the welfare of human beings is deeply linked to nature - to the existence in our world of a vast diversity of wild animals and plants. Because diversity has intrinsic value, and because its loss impoverishes society, we work to secure a future for all species, great and small, hovering on the brink of extinction. We do so through science, law, and creative media, with a focus on protecting the lands, waters, and climate that species need to survive.

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