October 17, 2019

EPA Identifies Potential Risks to Workers Who Handle the Herbicide Paraquat

EPA has published draft human health and ecological risk assessments for paraquat dichloride, an herbicide currently used to control weeds and grasses in agricultural and commercial settings. These draft risk assessments represent the next step in EPA’s regulatory review of paraquat as part of the Federal Insecticide, Fungicide, and Rodenticide Act registration review process. The agency’s draft human health risk assessment describes potential risks to workers who apply paraquat or enter treated fields after application. EPA also notes potential risks from spray drift to bystanders. The draft risk assessment identifies skin damage as the most commonly reported symptom for human exposure incidents resulting from occupational use of paraquat. Skin damage ranged from blisters and dry skin to chemical burns and lesions.

EPA assessed additional health hazards of paraquat by performing a “systematic review of the epidemiologic literature” on exposure to the herbicide.

“EPA reviewed a robust set of literature on paraquat exposure which included over 70 articles that investigated a range of health outcomes, including Parkinson’s disease, lung function and respiratory effects, and cancer,” the agency’s website explains. “Based on this review, EPA concluded that registered paraquat products do not cause Parkinson’s disease when used according to the label.”

Seventeen articles reviewed by EPA examined lung function and respiratory effects, and eight articles examined cancer outcomes. The agency’s report states that there is “insufficient epidemiologic evidence” of a clear link between occupational exposure to paraquat and health outcomes such as general lung function and respiratory symptoms, wheeze, allergic rhinitis, asthma, and chronic bronchitis. In the section of the report focused on cancer classification, EPA notes that paraquat is currently classified as “Category E,” which means that there is evidence of non-carcinogenicity for humans.

EPA’s draft ecological risk assessment identifies risk to mammals, birds, terrestrial invertebrates, terrestrial plants, and algae.

The agency seeks public input on its assessments from stakeholders such as environmental, human health, farm worker, and agricultural advocates; the chemical industry; pesticide users; and others. Comments will be accepted until Dec. 16, 2019. EPA intends to use the comments it receives to determine whether updates or revisions to the assessments are necessary. The agency will then propose additional risk mitigation measures, if necessary, in 2020. More information on submitting comments is available in the Federal Register notice.