Eight pesticides, including one of the most commonly used such compounds in the U.S., will get detailed reviews of their impacts on endangered species due to a legal settlement between the EPA and environmentalists.

Ending an eight-year court battle, the Environmental Protection Agency recently signed an agreement with the Tucson-based Center for Biological Diversity and a second group that will require the agency to conduct formal biological evaluations of the pesticides.

The pesticide on that list that’s raised the most concern among the environmentalists is atrazine, which is the second most commonly used herbicide in the United States after glyphosate.

Glyphosate is the active ingredient in Monsanto’s Roundup product that’s used widely on parks and crops around the country. The EPA has already agreed to conduct a similar review of the endangered species impacts of glyphosate, due to a separate court case.

Atrazine has come under increasing criticism from environmentalists and others over its impacts, and it’s been banned in the European Union countries for more than a decade. More than 75 million pounds of it are applied in this country yearly.

The EPA will conduct these evaluations as it weighs whether to re-register these pesticides for use under the Federal Insecticide, Fungicide and Rodenticide Act.

The upcoming evaluations are typically the first step toward preparing a full-scale biological opinion on the impacts of federal actions on imperiled species.

If a federal agency such as EPA concludes that the pesticides may affect the species, the onus then falls upon the U.S. Fish and Wildlife Service to prepare the biological opinions. Those are aimed at determining if the pesticides could either jeopardize a species’ existence or destroy or otherwise illegally damage its prime habitat.

If the wildlife service reaches such a finding, it must then determine what steps must be taken to mitigate the damage or come up with what’s known as a reasonable and prudent alternative to the pesticide in question.

The EPA wrote a fairly scathing risk assessment for atrazine’s ecological impacts back in 2016.

It found that aquatic plant communities are impacted in many areas where atrazine is heavily used, and that there’s a “potential chronic risk” from atrazine use to fish, amphibians and aquatic invertebrates at the same locations.

Overall, the EPA concluded that atrazine use in various areas exceeded the agency’s threshold for health concerns by up to 22, 198 and 62 times for birds, mammals and fish, respectively.

Other pesticides covered by the agreement that, like atrazine, are used to kill insects and/or weeds and other vegetation, are carbaryl, methomyl and simazine.

The agreement also covers four rodenticides commonly used as rat poison: brodifacoum, bromadiolone, warfarin and zinc phosphide.

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The agreement was approved on Oct. 18 in U.S. District Court in San Francisco.

The EPA’s review of impacts of atrazine and the other insect and weed killers must be completed by various deadlines during 2021, under the court-approved settlement. Its review of impacts of the four rodenticides must be completed by 2024.

“This victory requires the Trump EPA to finally protect some of our most endangered plants and animals from harmful pesticides,” said Stephanie Parent, a Center for Biological Diversity attorney. “This important step is only the start. We still have work to do to make sure the EPA addresses the harms of all pesticides, as the law requires.”

The center has other lawsuits pending seeking to force EPA to conduct similar endangered species reviews for eight other pesticides, said Parent, who works in Portland, Oregon.

The settlement provides a constructive path forward for completing certain biological evaluations and initiating consultations as necessary, an EPA spokesman said Friday. It also supports EPA’s Endangered Species Protection Program, the spokesman said. That program seeks to carry out EPA’s responsibilities under the Insecticide, Fungicide and Rodenticide Act.

But it’s unfortunate that “it takes a court order for EPA to put protection of our most endangered species above pesticide industry profits,” said Kristin Schafer, executive director of Pesticide Action Network North America. “Assessing the dangers of pesticides and taking action to protect public health and the environment is the agency’s job, and we’ll keep fighting until EPA fulfills its duty.”

The settlement doesn’t say how many of around 1,585 totally federally endangered and threatened plants and animals will be subject to these evaluations. That will be determined later.

Contact reporter Tony Davis at tdavis@tucson.com or 806-7746.

On Twitter@tonydavis987.