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Paraquat Dichloride


In October 2019, EPA took an important step in its regulatory review of paraquat—an herbicide used in agricultural and commercial settings only. The Agency is seeking public input on draft human health and ecological risk assessments. The draft risk assessments are the product of an extensive evaluation of available data on the health and environmental impacts associated with the pesticide. These draft risk assessments are the next step in the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) registration review process and are not a denial or an approval of the herbicide.

  • Read the draft risk assessments in docket # EPA-HQ-OPP-2011-0855. Upon publication of the Federal Register notice, public comments will be accepted in the docket until December 16, 2019.

After public comments on the human health and ecological risk assessments are reviewed, EPA will determine whether updates or revisions to the assessments are necessary. EPA will propose additional risk mitigation measures, if necessary, in 2020 via its Registration Review Proposed Interim Decision.

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Basic Information on Uses

Paraquat dichloride, commonly referred to as “paraquat,” is one of the most widely used herbicides in the United States. Paraquat is also often referred to as Gramoxone (a popular end-use product). It is an important tool for the control of weeds in many agricultural and non-agricultural settings. It is also used as a defoliant on crops, like cotton, prior to harvest.

There are no homeowner uses and no products registered for application in residential areas.

All paraquat products registered for use in the United States are Restricted Use Pesticides (RUPs), which can only be  used by trained certified applicators. 

Internationally, in 2013, the Parties to The Rotterdam ConventionExitconsidered a proposal to list liquid formulations containing concentrations of paraquat dichloride at or above 276 g/L as a severely hazardous pesticide formulation under Annexx III of the Convention. The Parties have been unable to reach consensus on the proposed paraquat listing and will consider it again in 2021. The Roterdam Convention is an international treaty designed to facilitate informed decision-making by its Parties regarding an agreed list of hazardous chemicals through the exchange of import consent notifications. The United States is not a party to the Convention.

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Using Paraquat Dichloride Products Safely

If you, your child or anyone else comes in contact with paraquat, seek medical assistance immediately. Ingestion of paraquat can be fatal, and dermal or eye contact can have serious lasting effects.

To prevent severe injury and/or death from paraquat ingestion, all paraquat product must:

  • Be used only by a certified applicator.
  • Never be transferred to a food, drink or any other container. New packaging requirements will prevent this from occurring.
  • Always be kept secured to prevent access by children and/or other unauthorized persons.
  • Never be stored in or around residential dwellings.
  • Never be used around home gardens, schools, recreational parks, golf courses or playgrounds.

To prevent severe injury and/or death from skin or eye exposure to paraquat:

  • Follow label instructions.
  • Use personal protective equipment.

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Human Health

Paraquat is highly toxic to people. One small sip can be fatal and there is no antidote.

Illegally transferring paraquat to beverage containers and later mistaking it for a drink has resulted in the accidental ingestion of the pesticide and caused several deaths since 2000. New packaging requirements and other risk mitigation measures required by EPA in 2016 are expected to prevent the illegal transfer of paraquat to beverage containers. Incidents also suggest that paraquat is corrosive to the skin and eyes.

In the 2019 draft human health risk assessment, EPA found no dietary risks of concern associated with paraquat when it is used according to the label instructions. The draft risk assessment identifies potential risks to workers who apply paraquat or enter treated fields after application. There are also potential risks from spray drift to bystanders at the edge of the field. 

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. Based on this review, EPA concluded that registered paraquat products do not cause Parkinson’s Disease when used according to the label. 

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Ecological Health

The 2019 draft ecological risk assessment identifies risk to mammals, birds, terrestrial invertebrates, terrestrial plants, and algae.

After EPA receives feedback on these assessments during our public comment period, the Agency will work with the pesticide manufacturer to mitigate the risks of concern if necessary.

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EPA Actions

Actions to Prevent Accidental Ingestion and Reduce Exposure to Workers

In 2016, to better prevent accidental paraquat ingestions and to reduce exposure to workers who mix, load and apply paraquat, EPA is requiring:

  • Changes to the pesticide label and distribution of supplemental warning materials to highlight the toxicity and risks associated with paraquat products.
  • Restricting the use of paraquat to certified pesticide applicators only. Individuals working under the supervision of a certified applicator are prohibited from using paraquat.
  • Specialized training for certified applicatorsExitwho use paraquat to emphasize that the chemical should not be transferred to or stored in improper containers.
  • New closed-system packaging designed to prevent transfer or removal of the pesticide except directly into proper application equipment. This will prevent spills, mixing or pouring the pesticide into other containers or other actions that could lead to paraquat exposure.

These mitigation measures are described in detail, along with implementation information in the Registration Review Docket. View the mitigation measures.

EPA distributed a safety message that highlights the toxicity of paraquat and illustrates the negative repercussions of misusing paraquat to pesticide application educators for use in training sessions. View EPA’s paraquat safety message

Registration Review

Paraquat is currently undergoing registration review, a program that re-evaluates all pesticides on a 15-year cycle. In October 2019, EPA released the draft human health and ecological risk assessments for public comment. 

After public comments on the human health and ecological risk assessments are reviewed, EPA will determine whether updates or revisions to the assessments are necessary. EPA will propose additional risk mitigation measures, if necessary, in 2020 via its Registration Review Proposed Interim Decision.

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Paraquat Dichloride Information Resources

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