The California Department of Pesticide Regulation (DPR) announced that all manufacturers of pesticide products containing the active ingredient paraquat-dichloride (paraquat) have voluntarily cancelled their product registrations, beginning the phase-out of the use of paraquat in California.
“For years, communities have fought to end the use of paraquat, a weedkiller associated with negative impacts to human health and wildlife,” said California Secretary for Environmental Protection Yana Garcia. “California will keep moving toward pest management practices that protect health and our ecosystems.”
DPR initiated the reevaluation of paraquat in November 2024, aligning with requirements in Food & Agricultural Code (FAC) section 14086, and released two preliminary scientific assessments the following month. DPR’s preliminary reports identified a potential association between paraquat exposure and thyroid impacts and birth defects. The reports also indicated paraquat may adversely affect other organisms, with the most significant risks to birds.
“We need the right data to identify where there are risks to people and the environment,” said DPR Director Karen Morrison. “This is a cornerstone of our continuous evaluation process to respond to evolving science on the impacts of pesticides.”
Reevaluation gives DPR the authority to require registrants – the companies that make pesticides – to develop and submit new scientific studies needed to fully understand emerging risks that were unknown at the time of registration. For paraquat, DPR invoked this reevaluation authority to require registrants to submit scientific data by June 5, 2026, to address newly identified gaps in DPR’s human health toxicology database, among other requirements. In lieu of providing required data, companies began voluntarily cancelling registration of paraquat pesticide products in California in April, with the last registrant voluntarily cancelling its registration on Aug. 6.
Under California law, DPR-licensed dealers may continue to possess and sell pesticides that were voluntarily canceled for up to two years following the effective date of each product’s cancellation. Growers who continue to use these products must act in accordance with all applicable label directions, use requirements, and state and federal regulations.
Paraquat reevaluation is part of a series of actions at the department to continuously evaluate and mitigate pesticide impacts. Status updates for other actions and pesticide active ingredients and classes under evaluation can be found on DPR’s Continuous Evaluation and Mitigation Update webpage.
DPR provides funding to research alternatives to pesticides and to increase access to safe, effective sustainable pest management (SPM) through its annual SPM Grants program. The 2027 priority areas include projects that are likely to decrease usage of pesticides prioritized for mitigation or evaluation by DPR, such as paraquat, and those that offer alternatives to weed management. The current application period is open through Sept. 1.
“To realize systemwide change in California, DPR plays a critical role in supporting additional research and outreach to move the state towards safer, more sustainable pest management approaches,” said Director Morrison. “As growers transition from the use of paraquat, the department will leverage available tools to support the use of effective alternatives and foster SPM.”
— Story contributed by the California Department of Pesticide Regulation