SAN FRANCISCO—Yesterday, Center for Food Safety (CFS) filed a new lawsuit in federal court challenging the Environmental Protection Agency's (EPA) March 2022 re-approval of difenoconazole, a potent fungicide increasingly sprayed on a wide range of fruits and vegetables, such as potatoes, tomatoes, and grapes, as well as soybeans. CFS alleges EPA unlawfully approved the toxic chemical despite animal studies showing that difenoconazole and similar fungicides cause liver tumors, reduce brain size, and impair reproductive organs, and despite evidence of harm to mammals, birds, pollinators, fish, and aquatic invertebrates.
"EPA has made yet another unlawful pesticide decision, putting its head in the sand instead of recognizing and addressing this fungicide's serious human health and environmental risks," said Meredith Stevenson, staff attorney at CFS. "EPA knows that it lacks critical information on human health impacts, yet failed to obtain the necessary studies and implement measures that could help reduce risks."
People are mainly exposed to these so-called triazole fungicides in food. In samples tested by U.S. Department of Agriculture via its Pesticide Data Program, difenoconazole residues were frequently detected in tomato paste and tomatoes (60.3% and 23.8% of samples, respectively), raisins (21.6%), grapes (8.5%), and potatoes (7.6%), among many other foods. Some triazoles are also approved for home use.
As far back as 2000, EPA was already so concerned about the toxicity of triazoles—in particular certain chemicals formed in plants sprayed with these fungicides—that it imposed a moratorium on further approvals until triazole manufacturers submitted a host of animal studies. The studies were to further assess triazoles' ability to impair the developing infant's brain and nervous system, to cause cancer, and disrupt hormonal systems. But even though the manufacturers refused to submit the studies, in 2006 EPA dropped the moratorium and opened the floodgates to approve a host of new triazole fungicides and new uses of those already approved.
"EPA should have stuck to its guns," said Bill Freese, science director at CFS. "Triazoles cause a host of neurological issues, and the "developmental neurotoxicity" study that EPA never obtained is critical because the developing infant's brain is far more sensitive to chemical disruption than an adult's," he added. "The fact that many triazoles induce liver tumors is also more than enough reason to assess them as a group, cumulatively, rather than one by one—as EPA has done."
EPA also failed to assess the role difenoconazole and other triazole fungicides have played in promoting resistance to life-saving antifungal drugs that are quite similar to agricultural triazoles. Resistant strains of pathogens such as Aspergillus fumigatus and Candida auris have become a huge, global public health threat, as the few antifungal drugs that can treat diseases such as life-threatening invasive aspergillosis become ineffective.
EPA also violated FIFRA and the Endangered Species Act (ESA) by leaving vulnerable species at risk from exposure to difenoconazole. For instance, in light of difenoconazole's extreme persistence in the environment, EPA acknowledged risks to fish and aquatic invertebrates, and to ground-dwelling bees, but re-approved difenoconazole nonetheless without effective measures to protect these organisms. This applies even more strongly to endangered species, which merit a higher degree of protection.