
The Link Between
Toxic Chemicals and
Parkinson’s Disease
Paraquat imports climb despite concerns about health impacts
The US has been importing increasing amounts of paraquat, a pesticide widely used in farming that is linked to Parkinson’s disease, even as other countries have banned the chemical amid growing concerns about risks to human and environmental health, according to the findings of a new report. Download the new report: Who Profits from Paraquat (Oct 2025)
Over a recent eight-year period, US imports of paraquat have totaled between 40 million and 156 million pounds per year, most coming from China and Chinese-owned manufacturing operations in the United Kingdom, the report states, citing import records. China announced in 2012 it was phasing out the use of paraquat and a ban in the UK took effect as part of a broad European Union paraquat ban in 2007. Dozens of other countries have also banned paraquat.
On average, paraquat imports have been on the rise since 2008, with a large spike seen in 2022, according to the report, which is a product of the Pesticide Action & Agroecology Network (PAN) and Coming Clean, both environmental health advocacy groups, and Alianza Nacional de Campesinas, an advocacy group for women farmworkers.
The report cites multiple Chinese factories as supplying paraquat to the US in recent years but singles out Sinochem Holdings, a Chinese government-owned company and parent to paraquat maker Syngenta, as among the key suppliers by way of a Syngenta manufacturing facility in central England.
Sales in the US are “helping to prop up demand for a toxic product with a shrinking global market,” the report states.
“The health and environmental harms of paraquat will be felt in US communities for generations - while the profits from paraquat sales largely flow outside the US, to a foreign-owned mega conglomerate,” the report states.
The groups behind the report advocate for banning paraquat and providing incentives for farmers to avoid use of all synthetic pesticides. They say paraquat is emblematic of broad problems across the pesticide industry.
“I hope this research shows that giant, foreign-owned companies are the ones profiting from weak US pesticide regulations,” said Deidre Nelms, spokeswoman for Coming Clean and author of Tuesday’s report.
“These companies can’t be trusted to solve the health and environmental problems they had a hand in creating in the first place,” she said. “Farming without pesticides is the only viable way to protect the health of the people who grow and harvest our food.”
A Syngenta spokesperson said it is one of more than 750 companies around the world that are registered to sell paraquat, and the pesticide accounts for only about 1% of the company's crop protection product sales globally and even less in terms of profitability.
"It's place in our innovation-focused portfolio reflects primarily our commitment to farmers who value paraquat for its effectiveness in protecting agriculturally important crops such as soy, corn and rice against invasive weeds," the company spokesperson said.

Specific concerns
The report points to specific concerns about disproportionate harm to Latine and low-income communities, citing a study of more than 800 Parkinson’s disease patients in California’s Central Valley. That report found that living within 500 meters of a paraquat application site over a prolonged period was associated with a 91% increase in the odds of developing Parkinson’s disease.
The report additionally states that every stage of the paraquat supply chain emits harmful greenhouse gases and toxic air pollutants. SinoChem’s paraquat supply chain includes fossil fuel extraction in Equatorial Guinea and Saudi Arabia, as well as chemical manufacturing in India, Germany and the UK, with final formulation and distribution in the United States, according to the report.
The report found a Syngenta facility in St. Gabriel, Louisiana, which formulates and packages the paraquat-based Gramoxone brand among other products, released over 52,000 metric tons of carbon dioxide in 2023, according to data from the US Environmental Protection Agency (EPA), and has sent more than 49,000 pounds of paraquat waste product to incinerators, an underground injection well and a toxic waste landfill over the last decade.
“Each stage of the Gramoxone supply chain, which spans four continents, causes toxic and climate-warming pollution,” the report states. “And only one powerful company profits.”
The Syngenta spokesperson said the paraquat waste totals were not unusual for the industry.
"We typically ship out only a few thousand pounds of paraquat-related waste for disposal each year," the company spokesperson said. "The carbon footprint of Paraquat production is not dissimilar to other chemical active ingredients."
Sinochem did not respond to a request for comment.
US trade policy under the Trump administration has encouraged continued imports of paraquat, the report notes, citing the administration’s exemption of paraquat (among other agricultural products) from tariffs imposed in April on Chinese imports. And in May, the US Department of Agriculture (USDA) rescinded a requirement that US farmers keep records of all their use of paraquat and certain other pesticides.
A “highly toxic pesticide”
In the US, paraquat is not sold for residential use and is only allowed for use by professional applicators. It is widely used by farmers to kill weeds in their fields, and to dry out crops for harvest. It is used in orchards, wheat fields, pastures where livestock graze, cotton fields and elsewhere. As weeds have become more resistant to the top-selling glyphosate herbicide, paraquat popularity with farmers has surged.
The US Geological Survey (USGS), which last published data on annual agricultural paraquat use in 2018, estimates that more than 17 million pounds of paraquat was applied that year on farmland, more than double the amount applied in 2008.
Despite its widespread use, the pesticide has become the subject of a nationwide public health and policy debate with many lawmakers and health advocates calling for state and federal bans on paraquat use.
A chief concern is scientific research dating back decades that links long-term paraquat exposure to disease, primarily the incurable brain disease known as Parkinson’s.
Last year, more than 50 US lawmakers called on the Environmental Protection Agency (EPA) to ban paraquat, calling it a “highly toxic pesticide” whose continued use cannot be justified givens its harms to farmworkers and rural communities.”
The lawmakers cited “numerous studies” that have found paraquat causes serious health risks that include a high risk of developing Parkinson’s disease, as well as risks of non-Hodgkin’s Lymphoma, thyroid cancer, and other issues.
The Michael J Fox Foundation for Parkinson’s Research has also urged a ban, providing the EPA with “a strong body of evidence” linking paraquat to Parkinson’s, including indications that paraquat may increase Parkinson’s risk by 100-500%.
A 2022 Parkinson’s Foundation-led study found that nearly 90,000 people are diagnosed with Parkinson's disease every year in the US.
Thousands of pending lawsuits
Syngenta has repeatedly denied there is any valid connection between Parkinson’s and paraquat.
But internal Syngenta documents revealed by The New Lede in a reporting project with The Guardian show the company was aware many years ago of scientific evidence that paraquat could impact the brain in ways that cause Parkinson’s, and that it employed many tactics to downplay and discredit that evidence and protect paraquat profits.
More than 8,000 people are currently suing Syngenta, alleging they or their loved ones developed Parkinson’s from paraquat exposure, and asserting that instead of warning of the risk of the incurable brain disease, Syngenta instead worked to hide the evidence of risk.
Syngenta is currently working to finalize a sweeping settlement agreement with some plaintiffs’ attorneys in hopes of ending the litigation, though some plaintiffs' attorneys oppose the deal and say it is deeply flawed.
The EPA states on its website that after reviewing the science, it has “not found a clear link” between paraquat exposure and Parkinson’s disease, though the agency does have a number of restrictions on use of the chemical due to its acute toxicity. The EPA, which was sued in 2021 by farmworkers and environmental groups over its re-approval of paraquat, had said it would issue an updated final report on paraquat in January 2025 but then said it needed more time.
The agency then said in a July court filing that it would be obtaining a study of paraquat volatilization to determine “the potential inhalation risks of paraquat for people who are not involved in the pesticide application.”
Featured photo is of transportation cargo containers. (Credit: Media handout from Syngenta Group)
This article first appeared on The New Lede and is republished here under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Paraquat Deadline Approaching | EPA to decide future of toxic Herbicide by Jan 15, 2025
PD Avengers joins coalition in calling for U.S. ban on Paraquat
Larry Gifford, President, PD Avengers:
“Continuing to utilize Paraquat in agriculture is akin to ignoring a ticking time bomb for neurological health. It's imperative that we recognize and act upon the clear link between Paraquat exposure and the rising incidence of Parkinson's disease."
EPA Takes Action On Harmful Chemical TCE
The Environmental Protection Agency (EPA) is ramping up efforts to protect people from
the dangers of trichloroethylene (TCE), a chemical commonly found in industrial and
consumer products. TCE, used in products like brake cleaners, furniture polish, dry cleaners
and arts and crafts sprays, has been linked to serious health risks including increased
risk of Parkinson’s disease. To address this, the EPA has introduced strict new rules under
the Toxic Substances Control Act (TSCA).
New Rules to Limit TCE
This month, the EPA issued a final rule banning the production, import, and sale of TCE for most
uses. This rule will take effect within one year for most products, protecting consumers, workers,
and communities from exposure.
For some specialized industrial uses, the ban will be phased in over a longer period. These industries will need to implement strict safety measures, such as a Workplace Chemical Protection Plan, to limit how much TCE workers breathe in.
Safer Workplaces
For industries where TCE use continues temporarily, the EPA has set a new exposure limit to reduce health risks. This change, based on public feedback, will lower workplace TCE exposure by 97%. However, even these uses will eventually be banned.
Some of the industries allowed more time to transition include:
Cleaning parts for aircraft and medical devices.
Manufacturing battery separators and refrigerants.
Maintaining equipment for transportation, security, and defense systems.
These exceptions aim to avoid disruptions to national security and critical infrastructure
while industries find safer alternatives.
Why This Matters
The new rules are part of a larger effort to reduce the risks posed by dangerous chemicals. In its 2020 evaluation, the EPA found that nearly all of TCE’s uses contributed to significant health risks. These new actions aim to reduce exposure and prevent further harm.
For more information, you can contact the EPA through their hotline at (202) 554-1404 or email TCE.TSCA@epa.gov. You can also visit regulations.gov and search for public docket EPA-HQ-OPPT-2020-0642 to stay updated on this issue.
By taking these steps, the EPA hopes to create a safer future and protect communities from the harmful effects of TCE.
Listen to this Podcast on TCE
What Paraquat Is: Paraquat is a highly toxic chemical used primarily as an herbicide for weed and grass control. In the U.S., it is available as a liquid and classified as "restricted use," meaning only licensed applicators can handle it.
Widely Used Herbicide: Paraquat is one of the most commonly used herbicides worldwide. It acts quickly and is non-selective, killing green plant tissue on contact.
Link to Parkinson's Disease: Paraquat exposure has been linked to an increased risk of developing Parkinson's disease. It contributes to oxidative stress in the brain, which is believed to play a role in the disease's progression.
Australian Petition
USA Petition
PD Avengers Toxic Chemical Page
Here are nine facts about Paraquat:
Bans and Restrictions: Paraquat is banned in 81 countries, including those in the European Union since 2007 and China since 2017. However, it remains widely used in the United States, Australia and other developing countries.
U.S. Usage: In the U.S., Paraquat use doubled between 2013 and 2018, reaching 10 million pounds annually. It is classified as a "Restricted Use Pesticide" and can only be handled by licensed applicators.
Controversial "Paraquat Pot" Program:
In the 1970s, the U.S. government supported a program where paraquat was sprayed on marijuana fields in Mexico to discourage drug use. Despite concerns about health risks, paraquat-contaminated marijuana ended up in the U.S. market, sparking debate about the potential harm to cannabis users.
Toxicity: It is highly toxic (lethal) to humans and animals due to its redox activity, which produces superoxide anions. Even a small dose can cause severe health effects, including fatal lung damage.
Extremely Small Lethal Dose: Paraquat is so toxic that ingesting as little as two teaspoons (10-20 ml) of a concentrated paraquat solution can be fatal. Unlike many other poisons, even spitting out paraquat after swallowing can still result in enough exposure to cause death.
Herbicidal Properties: It kills a broad range of weeds and grasses, works very fast, and becomes rain-fast within minutes of application. Upon contact with soil, it becomes partially inactivated, making it useful for no-till farming practices.
Victory for Advocacy: USGS Reverses Pesticide Data Cuts
BREAKING NEWS
Nathan Donley, Ph.D
Environmental Health Science Director
Center for Biological Diversity
Due to our collective voices and some pressure, the USGS has decided to relent and reverse its cuts to this important resource. If you’ll remember, the 2019 cuts to the pesticide maps and data included a reduction in the number of pesticides tracked (down to 72 from around 400 pesticides originally) and updates every five years instead of annually.
USGS’s recent commitment will see the lapsed pesticide data fully restored by 2025 and updated annually thereafter for the full suite of 400 or so pesticides. We will continue to try to pin down when in 2025 the data will be updated, as the usage data are already 6 years old at this point.
You can read the updated announcement on the mapping website here: https://water.usgs.gov/nawqa/pnsp/usage/maps/compound_listing.php
And a news story published today here: https://undark.org/2024/02/29/usgs-pesticide-database/
Unfortunately, data on seed treatment will not be restored as of now. USGS maintains that their data source for this resource does not collect this information anymore. We have confirmed that this is not entirely true, so we will be following up with the agency to keep advocating for the restoration of these sorely needed data.
But that’s a tomorrow problem, today we celebrate.
BREAKING NEWS
Role of the Exposome in Neurodegenerative Disease: Recent Insights and Future Directions
Stacey A. Sakowski PhD, Emily J. Koubek PhD, Kevin S. Chen MD, Stephen A. Goutman MD, Eva L. Feldman MD, PhD
First published: 27 February 2024
https://doi.org/10.1002/ana.26897
Abstract
Neurodegenerative diseases are increasing in prevalence and place a significant burden on society.
The causes are multifactorial and complex, and increasing evidence suggests a dynamic interplay between
genes and the environment, emphasizing the importance of identifying and understanding the role of lifelong exposures, known as the exposome, on the nervous system. This review provides an overview of recent advances toward defining neurodegenerative disease exposomes, focusing on Parkinson's disease, amyotrophic lateral sclerosis, and Alzheimer's disease. We present the current state of the field based on emerging data, elaborate on key themes and potential mechanisms, and conclude with limitations and future directions. ANN NEUROL 2024 (KEEP READING)
Summary by Larry Gifford
Neurodegenerative diseases are becoming more common as we age, causing big problems for healthcare and economies worldwide. That is the underlying message in a new review article in Annals of Neurology today (see below). Conditions like Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and Alzheimer's disease (AD) are on the rise and are expected to burden us even more in the future. While genes play a part, there's still a lot we don't understand about why people get these diseases. That's where the exposome comes in – it's all about looking at the lifelong environmental factors that might contribute to these conditions. This review dives into recent research on how things like where we live, what we eat, and what we're exposed to could affect our risk of developing neurodegenerative diseases. By using fancy new technologies and big research projects, scientists are starting to untangle the complex relationship between our environment and our health. But there's still a lot we need to learn, so this work is far from over.
Neurodegenerative Diseases on the Rise:
A Global Wake-Up Call
February 29, 2024
“Brain diseases are now the world’s leading source of disability. The fastest growing of these is Parkinson’s: the number of impacted patients has doubled to more than six million over the last twenty-five years (1990-2015) and is projected to double again by 2040. Harmful pesticides that increase the risk of Parkinson’s continue to proliferate, many people remain undiagnosed and untreated, research funding stagnates, and the most effective treatment is now a half-century old.”
ENDING PARKINSON’S DISEASE: A Prescription for Action
written by Ray Dorsey, MD ● Todd Sherer, PhD ● Michael S. Okun, MD ● Bastiaan R. Bloem MD, PhD
The Link Between Toxic Chemicals and Parkinson’s Disease
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Paraquat
Paraquat, a highly toxic herbicide, is used to kill weeds but is strictly handled by licensed applicators in the U.S. Its distinct blue dye and strong odor serve as warnings due to its extreme toxicity.
Exposure mainly occurs through ingestion or skin contact. A single sip is deadly for an adult. Long-term exposure may result in Parkinson’s disease, lung, kidney, or heart damage.
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Trichlorethylene (TCE)
Trichloroethylene (TCE) is an unstable, synthetic, colorless liquid initially developed as an anesthetic. Used in refrigerants, metal degreasers, and household products like cleaners, it poses health risks, especially Parkinson’s disease and non-Hodgkin’s lymphoma. Exposure occurs through air, water, or soil, particularly near production sites or military bases. Protection involves wearing gear, avoiding contaminated areas, and following product instructions to minimize exposure.
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Chlorpyrifos
Chlorpyrifos, an organophosphate insecticide, is a crystal-like substance with a faint odor similar to rotten eggs or garlic. Used widely since 1965, it combats pests like termites, mosquitoes, and roundworms. However, it's now phased out from food and animal feed crops due to high risks, especially for children. Chlorpyrifos disrupts nerve cell communication, causing the nervous system to malfunction, ultimately eliminating pests and leading to an increase of cancers and Parkinson’s Disease in humans.
EPA Revised Human Health Risk Assessment for Chlorpyrifos
The Link Between Toxic Chemicals and Parkinson’s Disease
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Paraquat
FACTS:
Banned in 65 Countries including; Austria, Brazil, Cambodia, Canada, Denmark, European Union (EU), Finland, Germany, Ivory Coast, Kuwait, Malaysia, Slovenia, Sweden, Switzerland, Syria, United Arab Emirates, United Kingdom.
Paraquat is a commonly used herbicide in the United States and India. It has lethal consequences even on minimal consumption.
Paraquat was first manufactured as a nonselective, quick-acting pesticide by a British chemical company in 1962. Though it was initially used to kill marijuana weeds in the United States and Mexico, it soon became popular worldwide as a cheap and effective pesticide.
According to the WHO (2022), some of the measures to prevent Parkinson’s disease include “banning of pesticides (e.g.: paraquat and chlorpyrifos) and chemicals (e.g.: trichloroethylene) which have been linked to PD and develop safer alternatives as per WHO guidance” and “accelerate action to reduce levels of and exposure to air pollution, an important risk factor for PD”. Paraquat is highly toxic.
There is no evidence that Paraquat has ever been used in chemical warfare or terrorist attacks.
Paraquat may be an excellent weed killer, but its effectiveness comes at an enormous price. A 2009 study in the American Journal of Epidemiology found that exposure to paraquat and another pesticide called maneb within 500 meters of one’s home increased the risk of Parkinson’s disease by a whopping 75 percent.
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Trichlorethylene (TCE)
FACTS:
TCE is a chemical that is commonly used as a solvent. It has a pleasant, sweet smell, though you can breathe it in without smelling it. TCE, linked to Parkinson’s, is so widespread in the American environment that nearly everyone has been exposed to it. It contaminates up to 30 percent of the country’s drinking water.
TCE contaminates countless industrial, commercial, and military sites. TCE is found in half of the 1300 most toxic “Superfund” sites that are part of a federal clean-up program, including 15 in California’s Silicon Valley where TCE was used to clean electronics. The U.S. military has stopped using TCE, but numerous sites have been contaminated, including the Marine Corps base Camp Lejeune in North Carolina.
Researchers found that TCE, much like radon, could evaporate from contaminated soil and groundwater and enter homes, schools, and workplaces.
Historical usage of trichloroethylene: Adhesives*, Aerosol cleaning products*, Carpet cleaner*, Cleaners and solvent degreasers*, Cleaning wipes*, Cosmetic glues, Decaffeinated coffee, Film cleaners, Glue, Gun cleaner, Fumigant, Hoof polishes, Inks, Lubricants, Mold release, Paint and paint removers*, Pepper spray, Pesticides, Refrigerant*, Sealants, Stain removers*, Tap and die fluid, Toner aid, Tool cleaners, Typewriter correction fluids*, Wood finishes*
Industry Usage
Automotive care, Dry cleaning*, Degreasing*, Furniture care, Manufacturing, Computer and electronics, Disinfectants, Dyes, Fat and oil extraction, Flavor extracts (spices, hops), Jewelry, Machinery*, Paint and coating*, Paper, Perfumes, Plastics, Refrigerant*, Soaps Medicine, Anesthesia (medical, dental, veterinary), Surgical disinfectant, Treatment (migraines, trigeminal neuralgia), and Pharmaceutical manufacturing.
*common current uses
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Chlorpyrifos
FACTS:
Chlorpyrifos (CPF), trade names Dursban and Lorsban,, is a widely used pesticide, is known to cause neuronal deficits and Parkinson's disease (PD).
CPF is an organophosphate compound utilized as a broad-spectrum pesticide, capable of killing a variety of insects and arachnids including pest larva, grubs, cockroaches, flea beetles, flies, termites, ants, and lice. It was introduced for use by Dow Chemical in 1965.
A nerve toxin, CPF holds the title of the most extensively used insecticide across various sectors, saturating golf courses and numerous crops such as almonds, cotton, grapes, oranges, and apples. Beyond its association with Parkinson's disease, it's also been implicated in adverse effects on children's brain development.
It’s most commonly used as an agricultural insecticide, and it is mostly used on cotton, corn, almond trees, and various fruit trees including apples, bananas, and oranges. Chlorpyrifos also finds non-agricultural use as a pesticide on golf courses, lawns, sporting fields, and in green houses. Finally, it often finds use as a non-structural wood treatment to prevent pest damage.
The primary ways in which chlorpyrifos finds its way into water sources are through
spray drift during application of the pesticide or through instances of significant soil erosion.
Chlorpyrifos’ health impacts:
• Decreased IQ
• Loss of working memory
• Attention deficits, like ADHD
• Autism
• Thyroid hormone disruption
• Reproductive problems
• Metabolic disturbances
• Nerve damage
• Parkinson’s disease
Must Read Articles, Investigations and Rulings
click any article or video to read or play
PARAQUAT
February 19th, 2024
February 9th, 2024
EPA ignores studies, reapproves Paraquat
-The Guardian
January 9th, 2023
TRICHLORETHYLENE (TCE)
December 21th, 2023
Toxic chemicals found at former dry cleaning site in Richmond
(READ MORE)
December 20th, 2023
March 17, 2023
TRICHLORETHYLENE (TCE)
June 30, 2021
In the more than five decades since its founding, the agency has canceled only 37 pesticides. (The EPA said that it has canceled 40 “pesticide products.”) Meanwhile, agrochemical companies have introduced thousands of pesticides. The EPA now manages more than 16,800 pesticide products and 1,200 active ingredients.
May 23, 2023
Veterans exposed to chemical at Camp Lejeune faced a 70% higher Parkinson’s risk, study says. (READ)
July 20, 2020
PARAQUAT
December 20, 2023
December 13, 2023
Journal of Parkinson’s disease: Towards improved screening of toxins for Parkinson’s risk Shan, L., Heusinkveld, H.J., Paul, K.C. et al. Dis. 9, 169 (2023). https://doi.org/10.1038/s41531-023-00615-9
November 22, 2023
PARAQUAT
December 6, 2023
March 22, 2023
November 12, 2023
PARAQUAT
December 15, 2023
June 2, 2023
December 20, 2016
CHLORPYRIFOS
March 15, 2023
September 1, 2021
November 3, 2023
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