WASHINGTON— Four public-interest organizations representing farmers and conservationists have made their legal case in a federal lawsuit against the U.S. Environmental Protection Agency and Monsanto. The opening brief, filed late Tuesday, challenges the approval of a pesticide that was designed to be sprayed on soybeans and cotton crops genetically engineered by Monsanto to tolerate being sprayed with dicamba.

Ignoring warnings of the potential for extensive damage to nearby crops from the drift-prone pesticide, the EPA first approved XtendiMax in late 2016. The groups sued the EPA in 2017, but in November 2018 the EPA renewed the pesticide’s approval before the court could issue its verdict, requiring further litigation.

According to researchers who track crop damage, the first two seasons of XtendiMax use were an unprecedented disaster. Just as critics warned, dicamba sprayed on Monsanto’s GE soybeans and cotton vaporized and drifted, resulting in damage to millions of acres of crops and wild plants.

“The evidence reveals that government officials — rather than protecting farmers and the public interest — have done whatever Monsanto has demanded to keep this pesticide on the market, forgoing the rigorous analysis and data that the law requires,” said George Kimbrell, legal director of the Center for Food Safety and counsel in the case. “It’s no wonder dicamba has had such devastating consequences: Its approval was illegal.”

Across much of the country, dicamba drift was linked to damage to more than 4 million acres of soybeans, as well as scores of vegetable and fruit crops, trees and shrubs. Flowering plants near croplands have also suffered, potentially harming pollinators and hundreds of endangered animal and plant species.

Agronomists reported that they had never seen herbicide-related drift damage approaching this scale before XtendiMax’s approval. As the 2019 season now unfolds, experts are already receiving similar reports of widespread crop damage.

“EPA ignored concerns of farmers, caving to Monsanto’s pressure and rushing dicamba-resistant seeds to market,” said Denise O’Brien, an Iowa farmer and board member of Pesticide Action Network. “EPA has failed utterly to protect farmers from this exploding crisis.”

The groups’ lawsuit details how the EPA was aware of the pesticide’s potential to drift and damage nearby crops but, at the request of Monsanto, approved the pesticide without putting any measures in place to prevent those risks.

The legal papers filed show that when the EPA came under mounting pressure in late 2017, and again in late 2018, to take some action to address the drift problem, the agency adopted revised instructions for the pesticide’s use proposed by Monsanto. The EPA ignored agronomists and state experts who correctly predicted the Monsanto-approved measures would not be effective in stopping the drift damage.

“The EPA’s foolish approval of dicamba left a deep scar across millions of acres of farms and forests,” said Nathan Donley, a senior scientist at the Center for Biological Diversity. “The ill-advised rush to approve this dangerous drift-prone pesticide reflects just how far the EPA has strayed from its duty to protect Americans and wildlife from harmful toxins.”

Beyond its failure to protect farmers, the EPA put hundreds of endangered species at greater risk. Despite the agency’s own conclusion that the approval might harm an extraordinary number of protected birds, mammals and insects across dozens of states, the EPA refused to seek the guidance of the federal expert wildlife agencies, as the Endangered Species Act requires. Instead, the agency denied that there would be any risk and approved the pesticide without any measures to protect endangered plants and animals.

“The Trump EPA’s reckless rush to appease Monsanto has pushed endangered whooping cranes, Karner blue butterflies, rusty patched bumblebees and hundreds of other species closer to extinction,” said Stephanie Parent, a senior attorney at the Center for Biological Diversity. “It’s disgusting but hardly surprising that Trump’s administration can disregard the law and the welfare of farmers and our most endangered plants and animals.”

By 2018 the EPA was forced to acknowledge that dicamba was vaporizing and drifting away from the fields where it was applied. In response, the agency added a new buffer requirement around fields being sprayed with the pesticide to increase protection for some endangered plants. But even when instituting these measures, the EPA’s political management overruled agency scientists and reduced the size of the buffer they had recommended from 443 feet to only 57 feet.

“Dicamba, an old generation toxic herbicide, was given new life as XtendiMax, due to the failure of Monsanto’s Roundup herbicide. Dicamba is still toxic, still highly drift-prone and still damaging to non-target crops. Will the buffer strips on my organic farm be adequate protection from the more volatile drift-prone nature of dicamba? I should not be put in the position to find out,” said Jim Goodman, a Wisconsin organic farmer who serves as board president of the National Family Farm Coalition. “In the eyes of EPA regulators, corporate profit is clearly more important than the health and livelihood of farmers and farm workers or damage to the environment.”

The organizations bringing the lawsuit are National Family Farm Coalition, Pesticide Action Network, Center for Food Safety, and Center for Biological Diversity, represented jointly by legal counsel from Center for Food Safety and the Center for Biological Diversity.