Paraquat, also referred to as paraquat dichloride, was registered as an herbicide in the United States in 1964. Its primary use is to control grass and weeds in many agriculture and non-agriculture sites. Many farmers also apply the herbicide pre-harvest on some crops. Plants that have become resistant to Roundup and other glyphosate-containing weed killers are popular targets. Also, the chemical is sometimes doused on illegal marijuana crops in the United States and Mexico. Some people have become ill after smoking contaminated marijuana.

U.S. farmers currently use more than 8 million pounds each year. Farmers of such crops as peanuts, citrus, wheat, soy, corn, almonds, artichokes, garlic, pears, strawberries, grapes, sweet potatoes, and cotton use paraquat.

Restricted use of Paraquat

In 2016, the EPA restricted the use of paraquat. The goal was to minimize accidental ingestions and reduce exposure to workers who mix, load, and apply the herbicide. Those restrictions included:

  • Requiring changes to the herbicide warning labels to highlight the toxicity and risks associated with paraquat products.
  • Restricting use to certified pesticide applicators only. Use by individuals working under the supervision of a certified applicator is also prohibited.
  • Requiring specialized training for certified applicators to emphasize that the chemical should neither be transferred to, nor stored in, improper containers.
  • Requiring new closed-system packaging to prevent transfer or removal of the pesticide except directly into proper application equipment. This protects users from spills, mixing, pouring the pesticide into other containers, or other actions that could cause exposure.

In October 2020, the EPA proposed new measures to better protect human health and the environment from the dangers of paraquat. The measures include:

  • Prohibiting aerial application for all uses except cotton desiccation.
  • Prohibiting pressurized handgun and backpack sprayer application methods on the herbicide label.
  • Limiting the maximum application rate for alfalfa.
  • Requiring a closed cab or PF10 respirators if the area treated in a 24-hour period is 80 acres or less.
  • Installing a residential area drift buffer and seven-day restricted entry interval for cotton desiccation.
  • Requiring a 48-hour restricted entry for all crops and uses except cotton desiccation.
  • Adding mandatory spray drift management label language.


Paraquat Exposure

Since paraquat is highly restricted, most people at risk for exposure are those who apply, mix, or load the weed killer, including:

  • Farmers and farmworkers
  • Agriculture workers
  • Crop dusters
  • Herbicide applicators
  • Chemical mixers
  • Tank fillers

In 1997, the EPA confirmed that the primary route of exposure to paraquat occurred during the weed killer’s preparation, application, and post-application. To minimize exposure risk, regulations require those who work with the highly toxic chemical to use chemical-resistant gloves made of barrier laminate, butyl rubber, nitrile rubber, neoprene rubber, natural rubber, polyethylene, polyvinyl chloride (PVC), or Viton. All must be equal to or greater than 14 mils. Applicators also must use respiratory protection and safety glasses that include splash guards. Mixers and loaders must add a full-face shield and a chemical-resistant apron.

Paraquat isn’t available for household use, but the EPA also said that individuals who live near farms using paraquat risk exposure to the weed killer. In 2009, a study published in the American Journal of Epidemiology backed up this finding, revealing that people who lived within 500 meters (about 1,600 feet) of paraquat use had a 75% increased risk of developing Parkinson’s disease.

Coincidentally, the American Parkinson Disease Association reported that individuals who met any of the following criteria were more likely to develop Parkinson’s:

  • Farming as an occupation
  • Exposure to farm animals
  • Living on a farm
  • Exposure to pesticides
  • Well water drinking
  • Living in a rural area


Paraquat exposure can occur through ingestion, skin contact, or inhalation. In some cases, exposure to the herbicide can cause paraquat poisoning.

Paraquat Poisoning Symptoms

Ingesting paraquat causes paraquat poisoning. Symptoms of paraquat poisoning come on quickly and include:

  • pain
  • swelling
  • immediate damage to the mouth, throat, and intestines
  • abdominal pain

Once the herbicide distributes to other parts of the body, paraquat poisoning causes toxic chemical reactions, primarily in the lungs, liver, and kidneys. Within days to weeks, lung scarring and heart, kidney, and/or liver failure can occur. If a person survives–which rarely happens if the person ingests a large amount–they will likely suffer long-term or permanent lung damage and possibly damage to other organs.

Skin Exposure

This is most likely to occur if the skin exposure lasts for a long time, involves a concentrated version of paraquat, or appears on broken skin, such as on a sore, cut, or severe rash.


If inhaled, paraquat can cause lung damage. Even if immediate symptoms don’t occur, exposure by inhalation “can provide a direct route of entry to the brain,” said Timothy Anderson, a graduate student and first author of a study published in the journal Toxicological Sciences.

Anderson’s research investigated the inhalation of paraquat in laboratory mice. He found that prolonged exposure caused mice to lose at least some of their sense of smell: an early sign of Parkinson’s disease.


Paraquat and Parkinson’s Disease

Previous research has associated both paraquat and another common weed killer called Maneb with an increased risk of Parkinson’s disease. In 2018, researchers from the University of Guelph in Ontario decided to look closely at this association. They found that low-level exposure to the pesticides disrupts cells in a way that mimics the effects of mutations known to cause Parkinson’s disease. “Adding the effects of the chemicals to a predisposition for Parkinson’s disease drastically increases the risk of disease onset,” they concluded.

A systematic review of paraquat-related literature conducted by researchers in 2019 also found that Parkinson’s occurrence was 25% higher in individuals exposed to the herbicide and even higher in those who were exposed to the chemical for more extended periods of time.

Another comprehensive study investigating exposure to 31 pesticides and their association with Parkinson’s risk found paraquat to be one of the most concerning weed killers among the group. Paraquat works by producing intracellular molecules that cause oxidative stress and damage cells. Interestingly, oxidative stress is a common theme in understanding what causes the death of nerve cells in people with Parkinson’s disease.

Yet another study revealed that people exposed to paraquat in their teens through young adult years had a 200% to 600% increased risk of developing Parkinson’s, depending on the overall number of years of exposure.

What is Parkinson’s disease?

Parkinson’s disease is a progressive nervous system disorder that affects movement. Symptoms start gradually and get worse over time. As the disease progresses, people can experience difficulty walking and talking. They may also experience mental and behavioral changes, sleep problems, depression, and memory difficulties. There is no cure for Parkinson’s disease, but medications and sometimes brain surgery can help improve symptoms.

Parkinson’s is caused by the breaking down and dying of certain nerve cells in the brain, called neurons. Many of the symptoms associated with the disorder are blamed on the loss of neurons that produce messengers called dopamine. Why this occurs remains a mystery. Researchers believe genetic mutations, environmental factors, and specific changes in the brain may play a role in developing Parkinson’s disease.

Symptoms of Parkinson’s disease

The four main symptoms of Parkinson’s disease include:

  • Tremor in the hands, arms, legs, jaw, or neck
  • Stiffness in the limbs and trunk
  • Slow movements
  • Impaired balance and coordination, which can make someone prone to falls

Other symptoms of Parkinson’s disease include:

  • Depression
  • Emotional changes
  • Difficulty swallowing, chewing, and speaking
  • Urinary problems or constipation
  • Skin problems
  • Sleep disruptions


Paraquat Brand Names

Paraquat is manufactured by various agrichemical companies under different brand names. One of the most popular brands sold in the U.S. is Gramoxone SL 2.0 Herbicide, made by Swiss-based agrichemical corporation Syngenta. Chevron Corporation held the rights to sell paraquat in the 1960s under an agreement with a company that Syngenta eventually purchased.

Other paraquat trade names include:

  • Para-SHOT 3.0
  • Helmquat
  • Parazone
  • Firestorm
  • Ortho-Paraquat
  • Quick-Quat
  • Devour
  • Blanco
  • Bonfire
  • Helmquat 3SL
  • Bonedry
  • Cyclone SL 2.0
Get Help now!

If you have been exposed to Paraquat and have been diagnosed with Parkinson’s or are experiencing symptoms of Parkinson’s disease, contact us.

If you or a loved one were diagnosed with Parkinson’s disease or is experiencing symptoms of Parkinson’s disease, you may be eligible for a lawsuit. A lawsuit can help recover damages for medical costs, pain and suffering, and more.

Contact us today for a free, no-obligation legal review.