A Environmental Health Victory That Also Exposes Systemic Regulatory Failure
On August 10, 2026—one day before a major legislative oversight hearing—the California Department of Pesticide Regulation (DPR) announced that manufacturers had voluntarily canceled all California registrations for pesticide products containing paraquat dichloride.
This is an important public health and environmental victory. However, the circumstances reveal how California’s pesticide regulatory system too often fails to act until forced by legislation, litigation, or sustained public pressure.
Paraquat’s Extreme Toxicity
Paraquat is an extremely, nonselective herbicide used to control weeds. In California, it has been applied to fruit and nut trees—including almonds and walnuts—as well as strawberries, grapes, carrots, alfalfa, cotton, and other crops.
DPR’s preliminary human-health and environmental reports identified potential associations between paraquat exposure and thyroid effects and birth defects. The reports also found that paraquat may harm nontarget organisms, including birds, mammals, and aquatic organisms, with birds facing the greatest potential risks. Independent studies have also reported associations between paraquat exposure and Parkinson’s disease. The product can be so life-threatening that it carries an EPA warning label “one sip can kill.” Paraquat poses serious health risks to applicators, farmworkers, and people living near treated fields.
Despite these concerns, paraquat remained widely used in California. In 2023, it ranked 46th among more than 1,000 pesticides used in the state. Approximately 369,978 pounds were applied across 338,975 acres, primarily in agricultural regions such as the San Joaquin Valley.
Years of Delayed Action
DPR identified paraquat as a priority for reevaluation in 2011 and ranked it the Department’s second-highest reevaluation priority in 2014. Yet no decisive action followed for years.
More than 70 countries have banned or severely restricted paraquat, including the European Union, which banned it in 2007. California, by contrast, did not begin a formal reevaluation until November 2024—after the Legislature enacted AB 1963 (Friedman, 2024). The law requires DPR to complete its paraquat reevaluation by January 1, 2029.
As part of that process, DPR requested additional human-health toxicology data from paraquat manufacturers, with a submission deadline of June 5, 2026. Rather than provide the requested studies, the manufacturers voluntarily canceled their registrations. The final cancellation occurred on August 6, and DPR announced on August 10 that every paraquat manufacturer had exited the California market.
The outcome is welcome, but it was not the result of timely, proactive regulatory leadership. Without the statutory deadline, California’s long-delayed reevaluation might not have produced this result.
Cancellation Is Not a Ban
Voluntary cancellation is different from a regulatory ban or suspension. Manufacturers have left the California market, but they did so without releasing the human-health data requested by DPR—information that could be relevant to regulators and communities elsewhere.
As Assemblymember Nick Shultz (D-Burbank) raised during the Oversight Hearing:
Shouldn’t we, as the legislative branch of the state government, and more broadly, shouldn’t we, as the public, be concerned when pesticide manufacturers decide to voluntarily cancel registration of their products rather than providing the data requested by the department regarding their impact on human health and the environment?
California law also allows licensed dealers to possess and sell existing stocks of voluntarily canceled products for up to two years after each product’s cancellation date. As a result, some paraquat products may remain available in California into 2028, and growers may continue using existing supplies until they are depleted.
A Broader Pattern
Paraquat is not an isolated example. DPR placed chloropicrin—a highly hazardous soil fumigant used as a chemical weapon during World War I—under reevaluation in 2001. No legislation or litigation forced that action. Yet 25 years later, chloropicrin remains widely used. In 2023, California growers applied approximately 8.5 million pounds of it.
The paraquat episode therefore represents both meaningful progress and a warning. A 2024 legislative mandate was needed after years in which paraquat held a high-priority status without decisive DPR action. Meanwhile, other hazardous pesticides have remained under reevaluation for decades.
The voluntary cancellations are long-overdue good news for public health. But the delayed timeline, the absence of requested manufacturer data, and the continued sale of existing stocks expose deeper structural weaknesses in California’s pesticide regulatory system.
Californians deserve a Department that acts before communities are forced to demand action.