US lawmakers call on EPA to ban pesticide linked to Parkinson’s disease

More than 50 US lawmakers are calling on the Environmental Protection Agency (EPA) to join dozens of other nations in banning a widely used weed killer linked to Parkinson’s disease and other health dangers.

In a 31 October letter to the agency, seven US senators said that paraquat, a weed killer commonly applied on US farms, was a “highly toxic pesticide whose continued use cannot be justified given its harms to farmworkers and rural communities”. The call for a ban from the senators came after 47 members of the US House of Representatives sent a similar letter to the EPA calling for a ban earlier in October.

The lawmakers cite scientific links between paraquat use and development of Parkinson’s and other “life threatening diseases” as well as “grave impacts on the environment”. “Health risks include a higher risk of Parkinson’s disease, with some studies finding a 64% increase in the likelihood of developing Parkinson’s, non-Hodgkin’s Lymphoma, thyroid cancer, and other thyroid issues,” they wrote.

New Jersey senator Cory Booker, organizer of the Senate letter, said the risks of paraquat exposure are “well documented” and that it is “irresponsible” for the EPA to continue to allow its use. “I hope the EPA will follow the science and ban paraquat,” Booker said.

The EPA has long maintained that there is no “clear link” between paraquat exposure and Parkinson’s disease, though the agency does have a number of restrictions on use of the chemical due to its acute toxicity. The agency issued a draft report earlier this year affirming its position.

Still, the agency said at that time that it would be reviewing more scientific studies and would issue a final report by 17 January 2025.

When asked about the congressional call for a ban, an EPA spokesperson said only that the agency “will respond to the letter appropriately”.

Several California lawmakers pushed for a ban in the most recent state legislative session, also citing the risks of Parkinson’s. A compromise measure signed by the governor last month requires an expedited regulatory review of paraquat.

The push to ban paraquat in the US is “long overdue”, said Ray Dorsey, a professor of neurology at the University of Rochester who studies the causes of Parkinson’s disease.

“For 60 years, paraquat has been helping fuel the rise of Parkinson’s disease,” Dorsey said. “The evidence from human, laboratory and apparently even the company’s own research is overwhelming. When paraquat is banned, more lives will be spared the consequences of Parkinson’s.”

Chinese-owned Syngenta, the longtime maker and marketer of paraquat products did not respond to a request for comment about the congressional letters, The company has denied there is any valid connection between Parkinson’s and paraquat. In response to previous reporting, it asserted that no “peer-reviewed scientific publication has established a causal connection between paraquat and Parkinson’s disease”.

Internal Syngenta documents revealed by the Guardian show the company was aware many years ago of scientific evidence that paraquat could impact the brain in ways that cause Parkinson’s, and that it secretly sought to influence scientific research to counter the evidence of harm.

Syngenta was allegedly aided in suppressing the risks of paraquat by a “reputation management” firm called v-Fluence, the Guardian reported in September.

Thousands of US paraquat users who suffer from Parkison’s are currently suing Syngenta, alleging the company should have warned them of the risk of developing the incurable brain disease, but instead worked to hide the evidence of risk.

This story is co-published with the New Lede, a journalism project of the Environmental Working Group