Toxic herbicide used on U.S. farms is linked to Parkinson’s disease
EWG | Anne Schechinger | March 6, 2026
The agricultural chemical and seed giant Syngenta announced it will stop producing the toxic weedkiller paraquat by the end of June this year.
But this is a tactical retreat, not a public health victory.
Syngenta currently produces paraquat at just one plant, in the United Kingdom. It will cease production of paraquat at the facility before July. But the decision is unlikely to significantly reduce the use of paraquat on U.S. farms, where it remains widely sprayed, despite growing evidence linking it to Parkinson’s disease and other serious health harms.
The reason it may not make much of a difference to use in the U.S. is that other companies will continue to produce paraquat as an active ingredient in herbicides. Globally, 377 companies are registered to produce the generic active ingredient.
China is the largest producer of paraquat due to other companies that manufacture it there, even though the weedkiller’s application is banned in the country. Syngenta is owned by the Chinese state-owned corporation ChemChina.
At least 70 countries have banned paraquat because it threatens the health of people exposed to the chemical. That includes the U.K., where Syngenta has been manufacturing paraquat, and China, where ChemChina is based.
U.S. application of paraquat
Ten million pounds of the active ingredient were applied in the U.S. in 2017, one of the most recent years for which data is available.
In addition to Parkinson’s disease, exposure to paraquat has been linked to non-Hodgkin lymphoma, childhood leukemia and more. Farmers, farm workers and people who live near farm fields sprayed with the pesticide are at greater risk from exposure.
While Syngenta’s decision is a step in the right direction, it said nothing about whether it will continue to sell paraquat-based herbicides, such as Gramoxone, after it has ceased production.
Paraquat is a generic active ingredient used in many herbicides. Because it is generic, over 750 different companies sell paraquat globally. In the U.S., that includes Drexel Chemical Company, Helm Crop Solutions, Anhui Costar Biochemistry, Helena Agri Enterprises, Nanjing Red Sun Biochemistry, Solera and RedEagle International.
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