California has canceled its last remaining paraquat pesticide product, enacting restrictions that require existing stocks to be sold or destroyed within two years. The decision by the California Department of Pesticide Regulation comes as families in Ladera Ranch, an Orange County community, continue to investigate a cluster of rare childhood cancers.
Paraquat, the active ingredient in commercial weedkillers such as Gramoxone and Firestorm, has been linked to Parkinson's disease and is considered one of the most lethal herbicides approved for use in the United States. The chemical has no antidote, and exposure can lead to severe health issues including cancer, heart, kidney, and liver failure, as well as lung scarring. The Environmental Protection Act warns that "One Sip Can Kill."
This move follows years of advocacy from farmworker groups, environmentalists, and health organizations. California is the largest user of paraquat in the nation, with over three-quarters of its application concentrated in eight San Joaquin Valley counties. It ranks among the state's top five most-used pesticides.
The state's preliminary assessment, conducted after conservation and public health groups pushed for a ban, identified potential risks to wildlife, including the San Joaquin kit fox and Swainson's hawk. Officials also noted concerns about the chemical's persistence in the environment and potential public health risks, including associations with thyroid disease and reproductive harm.
In Ladera Ranch, approximately nine children connected to the community have been diagnosed with Ewing sarcoma, a rare cancer primarily affecting young people, since 2007. While health officials have not identified an environmental cause, residents have questioned whether years of pesticide and herbicide use could be a contributing factor. Two young individuals, Brody Matteson, 17, and Lily Dalton, 23, have died from the disease. In response, the Capistrano Unified School District announced a 60-day pause on routine pesticide and herbicide applications on its campuses, and the Ladera Ranch Maintenance Corporation also implemented a temporary pause on certain landscape chemicals.
While local concerns in Ladera Ranch have not been officially linked to paraquat, the timing has amplified scrutiny of pesticide exposure. The state's review of the herbicide was mandated by A.B. 1963, passed in 2024. Farmworkers and agricultural communities are particularly vulnerable, as paraquat can drift into neighborhoods via dust. Research has indicated that exposure in California agricultural communities is associated with increased risks of Parkinson's disease and thyroid cancer.
California's action contrasts with the federal government's approach. Vermont has already enacted its own paraquat ban, while the EPA has announced plans for a stakeholder roundtable to discuss regulation. Nathan Donley, environmental health science director at the Center for Biological Diversity, criticized the EPA's pace, stating, "California and other states are taking aggressive steps to protect people from this dangerous poison, but the EPA continues to spin a web of red tape to obscure paraquat’s well-documented harms." A lawsuit filed by farmworker groups, environmentalists, and health organizations represented by Earthjustice against the EPA in 2021 over its reapproval of paraquat remains ongoing.
The Ladera Ranch situation has also drawn federal attention. First Assistant U.S. Attorney Bill Essayli has requested that EPA Administrator Lee Zeldin investigate potential environmental factors and violations of federal environmental laws related to the reported cancer cases.