California is pulling a notorious weedkiller from the market as families in a Southern California community continue to demand answers over a string of rare childhood cancers.
The California Department of Pesticide Regulation announced Monday that the state’s last paraquat pesticide product has been canceled.
Existing stocks must be sold or destroyed within two years.
Paraquat is the active ingredient in heavy-duty commercial weedkillers like Gramoxone, Para-SHOT, Helmquat, Cyclone, and Firestorm.
The move follows years of pressure from farmworker groups, environmentalists and health organizations.
Paraquat has been linked to Parkinson’s disease and is banned in more than 70 countries.
It is also considered one of the most lethal herbicides approved for use in the US.
There is no antidote for paraquat poisoning.
An Environmental Protection Act website carries the stark warning: “Paraquat Dichloride: One Sip Can Kill.”
Exposure can cause serious health problems even when it is not fatal, including cancer, heart failure, kidney failure, liver failure and scarring of the lungs.
California is the nation’s largest user of paraquat, with more than three-quarters of its use concentrated in eight San Joaquin Valley counties.
The chemical ranks among the state’s five most-used pesticides.
The crackdown comes as pesticide use is already under scrutiny in Ladera Ranch, an affluent Orange County community where residents have raised alarms over a reported cluster of rare childhood cancers.
Since 2007, about nine children connected to the community have been diagnosed with Ewing sarcoma, a rare cancer that primarily affects children and young adults.
Health officials have said no environmental cause has been identified, while families have questioned whether years of pesticide and herbicide use could be a factor.
The toll has been devastating. Brody Matteson, 17, died in March 2026 after battling Ewing sarcoma for nearly two years.
Lily Dalton, 23, died in January 2026 after battling the disease following her college graduation.
The Capistrano Unified School District recently announced a 60-day pause on routine landscape chemicals, including herbicides and pesticide sprays, while officials review approved products.
The Ladera Ranch Maintenance Corporation also announced a temporary pause on certain landscape chemicals.
The local concerns have not been linked by officials to paraquat, but the timing has put a spotlight on the broader question of pesticide exposure.
California began reevaluating paraquat after conservation and public health groups sought to have its use banned. A.B. 1963, passed in 2024, required the state to continue reviewing the herbicide.
The state’s preliminary assessment found potential risks to birds and mammals, including the San Joaquin kit fox and Swainson’s hawk.
Officials also warned that restrictions meant to protect wildlife may not work because paraquat is so persistent in the environment.
The review found public health concerns including an association between paraquat and thyroid disease, as well as birth and reproductive harms.
Farmworkers and agricultural communities can face greater exposure because paraquat can spread in dust blowing from fields into neighborhoods.
Researchers have found that exposure in California agricultural communities is associated with increased risks of Parkinson’s disease and thyroid cancer.
California’s move contrasts with the federal government’s approach.
Vermont has already enacted the nation’s first paraquat ban, while the EPA recently announced plans for a roundtable with stakeholders to discuss regulation of the chemical.
“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,” said Nathan Donley, environmental health science director at the Center for Biological Diversity.
“The writing is on the wall — paraquat is on its way out. The question now is how long it will take the EPA to actually do its job and start protecting people instead of the profits of pesticide companies.”
Farmworker groups, environmentalists and health organizations represented by Earthjustice sued the EPA in 2021 over its reapproval of paraquat
That legal challenge remains ongoing.
And the Ladera Ranch controversy has now reached Washington.
Last month, First Assistant US Attorney Bill Essayli asked EPA Administrator Lee Zeldin to investigate whether environmental factors could be contributing to the reported cancer cases and whether federal environmental laws may have been violated.
