Paraquat Linked to Parkinson’s Disease, Prompting Legislative Action

California has taken a significant step towards banning the controversial herbicide paraquat, as a pivotal state legislative committee approved the measure on Thursday. The proposed ban, set to take effect on January 1, 2026, would prohibit the use, manufacture, sale, delivery, holding, or offering for sale of any pesticide product containing Paraquat. The bill includes a provision allowing state regulators to reevaluate Paraquat and potentially reapprove it with or without new restrictions.

5 Key Points

  • California’s proposed paraquat ban is driven by concerns over the chemical’s link to Parkinson’s disease.
  • Thousands of farmers, agricultural workers, and others are suing paraquat maker Syngenta, alleging they developed Parkinson’s due to long-term exposure.
  • Internal Syngenta documents reveal the company’s awareness of Paraquat’s potential health risks and efforts to influence regulatory bodies and public opinion.
  • Parkinson’s disease rates have been climbing in the United States, with the death rate increasing by more than 60% over the past two decades.
  • Several countries, including the European Union, UK, Switzerland, and China, have banned Paraquat due to safety concerns.

Paraquat’s Widespread Use and Controversy

Paraquat is one of the most widely used weed-killing chemicals worldwide, with farmers using it to control weeds before planting and to dry out crops for harvest. In the United States, the chemical is used in orchards, wheat fields, pastures, cotton fields, and other agricultural settings. Despite Syngenta’s claims that Paraquat is safe when used according to directions and with proper protective equipment, the chemical has been banned in dozens of countries due to acute dangers and mounting evidence of health risks, such as Parkinson’s disease, from chronic, long-term exposure.

Secret Syngenta Records and Influence

Assemblymember Laura Friedman’s office cited internal Syngenta documents uncovered by The New Lede and The Guardian, which reveal the company’s long-standing awareness of scientific research linking Paraquat to Parkinson’s disease. These documents also show evidence of Syngenta’s efforts to manipulate and influence the EPA and the publication of scientific literature supporting Paraquat’s safety. The company allegedly worked to mislead the public about Paraquat’s dangers and employed secret strategies to maintain the chemical’s market presence.

California’s Proactive Approach to Chemical Regulation

California has a history of taking quicker action than the US Environmental Protection Agency (EPA) in restricting chemicals associated with severe health concerns. In 2019, after the EPA failed to follow through on plans to ban the insecticide chlorpyrifos, California announced its ban, citing evidence of the chemical’s association with impaired brain and neurological development in children and other sensitive populations.

The paraquat ban bill will now be voted on by the entire Assembly next week. A majority of 80 Assembly members is required to keep the measure alive. If successful, the bill will move to the state Senate for consideration.