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Pesticide paraquat gets green light from US EPA

Agency allows aerial spraying of toxic herbicide linked to Parkinson’s disease

by Britt E. Erickson
August 4, 2021 | A version of this story appeared in Volume 99, Issue 29


chemical structure of paraquat

The acutely toxic herbicide paraquat can stay on the US market with new safety measures to reduce farmworker exposures, the Environmental Protection Agency says in an interim decision announced Aug. 2. The decision comes as the pesticide’s manufacturer Syngenta and distributor Chevron USA face more than 100 lawsuits from agricultural workers who claim their exposure to paraquat contributed to Parkinson’s disease.

The EPA acknowledges the acute toxicity of paraquat, stating on its website “One small sip can be fatal and there is no antidote.” But the agency dismisses several scientific studies that link paraquat exposure to Parkinson’s disease, claiming the studies vary in quality and provide conflicting results.

Under the Trump administration, the EPA proposed banning most aerial spraying of paraquat. But after reviewing data from the pesticide industry, the agency now says aerial applications are allowed with some restrictions, including no-spray buffers in residential areas. Other new measures include prohibiting the use of pressurized spray guns, backpack sprayers, and human flaggers on the ground to guide airplanes spraying paraquat. The agency also is requiring enclosed vehicle cabs or use of respirators for ground applications, and is increasing the amount of time workers must wait before entering treated areas.

Paraquat is commonly used on agricultural crops, including soybeans, corn, and cotton, as well as on sites such as rights-of-way and commercial buildings. Its use is on the rise in the US as weeds develop resistance to other herbicides such as glyphosate. The illegal transfer of paraquat into beverage containers led to cases of accidental ingestion and death, prompting the EPA to impose label and packaging changes in 2016.

Environmental groups are disappointed that the EPA continues to allow use of paraquat in the US. The herbicide is prohibited in the European Union, China, and Brazil because of its health risks to agricultural workers.

“Instead of banning a weedkiller linked to Parkinson’s disease in farmworkers, reproductive harm in small mammals and increased death rates for birds, this administration is bowing to the wishes of the chemical industry and allowing it to be sprayed on crops from the air,” Nathan Donley, environmental health science director at the Center for Biological Diversity, says in a statement.


This story was updated on Aug. 9, 2021, to change the name of the defendant from Chevron Phillips Chemical to Chevron USA.



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