This Weed Killer Is Linked to Parkinson’s. Why Isn’t It Banned Yet?

Paraquat damages farmworkers’ respiratory system, their kidneys, and their eyes. Help us urge the EPA to ban it.

A close up photo of Lori Phillips near a tree
Lori Phillips grew up in Franklinville, New York where her family lived on a farm, growing corn and raising livestock. During the summer, the windows of her house would be open while her father sprayed a herbicide on the crops. Years later, Lori developed Parkinson’s disease. (Tina Russell for Earthjustice)

Paraquat is a deadly herbicide that has been linked to Parkinson’s disease in farmworkers and agricultural communities. It’s already been banned in more than 50 countries. But in the U.S., paraquat is still widely sprayed on farms despite staggering evidence that it harms people’s neurological functioning.

On behalf of farmworker, public health and environmental organizations, Earthjustice sued the U.S. Environmental Protection Agency (EPA) in 2021 for allowing paraquat to remain on the market despite strong scientific evidence of the harm it causes. In response, the EPA agreed to take another look at that decision.

The data is quite clear. Paraquat damages farmworkers’ respiratory system, their kidneys, and their eyes, which the EPA concedes. A National Institutes of Health study found that workers who have used it are 2.5 times more likely to develop Parkinson’s, and a study published earlier this year found that people who live near the fields where paraquat is sprayed also experience increased Parkinson’s disease risks.  Yet the EPA reauthorized the widespread use of paraquat without addressing its neurological risks.

Thousands of people have stories of contracting Parkinson’s after being exposed to paraquat. Take Lori Phillips, for example, a 67-year-old woman who grew up on a small family farm in New York. “I can still remember the smell of the crops being sprayed by my bedroom window,” she says. “This was in the early 1960s, about the time that paraquat was put on the market.”

Four old color and black and white photos of farm life, including a girl on a bicycle, a toddler and young boy, kids with cows and a tractor, being held by Lori Phillips.

Lori Phillips looks at old photos of herself and her family on the farm she grew up on in Franklinville, New York. (Tina Russell for Earthjustice)

Fast forward 50 years and Phillips’ mother, brother, and uncle were all diagnosed with Parkinson’s. She and her brother were tested for the genes linked to Parkinson’s, and neither had any of them, suggesting environmental factors were at play.

Despite not always having control of her arms, which hang rigidly at her side, or her feet, which shuffle when she walks, Phillips stays active as best she can. But the old Phillips — who could run marathons and type 120 words a minute at work, was an avid sewer, and planned to travel throughout retirement – is gone.

People tend to know about the slurred speech and trouble with movement that characterize Parkinson’s. But less well-known is the link between Parkinson’s and depression as the disease drains the brain of dopamine.

“Sometimes the medicine works and sometimes it doesn’t,” she explains. “It affects cognitive thinking. It affects your speech. You get constipated. You get dementia very easily. You get depressed.”

Then there’s the financial stress. There’s no generic version of Ongentys, the medicine Phillips takes; a 90-day supply costs $1,900. And that’s just one pill, before you get to the others and all the supplements that health insurance won’t cover. To get by, Phillips, like many others, gets grants from non-profit organizations that help them pay for medicine.

But there’s no guarantee how long that will go on. And because of her Parkinson’s, Phillips does not qualify for long-term care insurance, which makes her future precarious at best.

Earthjustice is fighting to press the EPA to do what it should have done years ago – to ban paraquat. But we’re up against chemical companies with deep pockets who will go to great lengths to bury the evidence of paraquat’s harm. And the EPA’s latest analysis of paraquat continues to overlook the overwhelming evidence linking the herbicide to Parkinson’s disease.  The EPA needs to hear from people like you that it should ban this deadly chemical. This month marks the start of 60-day comment period where people can make their feelings known to the EPA.

What is paraquat? What are paraquat’s health harms?

It’s an herbicide used on farms to stop weeds from growing. It’s quite good at killing weeds – but it’s lethal for people too. And it disrupts normal neurological functioning. It’s been linked to a host of serious diseases in humans, including Parkinson’s and kidney disease.

The risks skyrocket the longer you’re exposed to it, which puts farmworkers at great risk. It can also cause migraines, and dizziness on a day-to-day basis for people who handle it.

Chemicals being sprayed on a field of crops

A tractor sprays pesticides on crops. (sircco / Getty Images)

Who faces the greatest risks from paraquat?

Scientific research has not found that there is a health risk to people who eat food treated with paraquat at the levels approved by the EPA. But the EPA has found that the approved use of paraquat presents serious health risks to farmworkers, and studies have shown harm to the communities surrounding the farms where paraquat is sprayed. Thousands of people across the world have also died from paraquat ingestion, since one small sip is enough to kill and there is no known antidote.

Despite the dangers of paraquat and the existence of safer alternatives on the market, paraquat’s use doubled between 2012 and 2018.

Why is paraquat still on the market?

Paraquat has already been banned in more than 50 countries, including all the countries in the European Union. The two places where it’s actually made — the UK and China – ban its use. But here in the U.S., chemical manufacturers still have a good deal of leverage in the political process. So they put pressure on regulators and put up their own experts to sew doubt over the scientific evidence linking paraquat to Parkinson’s disease. Syngenta, the company that manufactures paraquat, continues to sell the deadly chemical in the U.S., Australia, New Zealand, Japan, and Indonesia

Syngenta denies the evidence linking paraquat to Parkinson’s and other health harms. An investigation by The Guardian and the New Lede in 2022 showed that Syngenta suppressed evidence of paraquat’s presence in the brain, withheld key data related to paraquat’s harms from the EPA, and fought to keep scientists who had documented the connection between paraquat and Parkinson’s disease off an influential EPA peer review panel.

What have you heard from people exposed to paraquat?

“We’d go out spraying and get it on our skin. Our boots were soaked in the chemical. I am very athletic, played football in college. Then I noticed at the age of 37, my gait was foreshortened on the right side, badly so I could barely get across a parking lot.”

John Kelly, who worked for a lawn company spraying paraquat from ages 13 to 16

“My life is dramatically changed. I have slowness of movement. I don’t qualify for long-term care insurance if I have to go into a long-term care facility. How do you even survive when you’ve got $3000 a month in medicine?”

Lori Phillips, person with Parkinson’s

“He cannot walk unassisted without falling – the problem now is the constant falling. He has cut his head open and had 10 metal stitches in his head. He ended up having a blood clot in his arm from a fall. Those kinds of things happen. He’s on many medications. His pillbox contains 25 pills just to function. One of the medications is for hallucinations he has had in the past – if we had to pay the out-of-pocket, even with insurance, it would be over $2000 a month. “

Irene Miller, a support group leader who cares for her husband who has Parkinson’s

What is Earthjustice’s role in fighting to get paraquat banned?

We sued the EPA when the agency renewed the registration for the chemical, reauthorizing its widespread use for another 15 years. Our clients include Farmworker Association of Florida, Farmworker Justice, Alianza Nacional de Campesinas, California Rural Legal Assistance Foundation, The Michael J. Fox Foundation for Parkinson’s Research, Pesticide Action Network North America, Center for Biological Diversity, and Toxic Free North Carolina.  Our lawsuit claims that the EPA violated the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) by failing to adequately consider the risks of Parkinson’s disease, ignoring key exposure pathways, and leaving farmworkers and agricultural communities exposed to unreasonable risks.

In response to our suit, the EPA has agreed to take a new look at the science and let the public weigh in. This is a crucial period to show the EPA that the paraquat presents unacceptable health risks and must be banned.

What could happen next?

In early 2025, the EPA will finalize its reassessment on paraquat’s risk, making its decision based partly on public input. We are pressing the EPA to issue an outright ban of paraquat, as dozens of other countries have already done. It remains to be seen whether the United States will join them. Earthjustice members have an important role to play because we know the EPA is hearing from the chemical lobby. They need to hear from us too.

Tell the EPA to ban paraquat now.

Jessie Torrisi is a storyteller based in Los Angeles. She's worked with a dozen social justice NGOs as a writer, editor, and communications strategist. She loves writing about the human side of policy and legal issues — and what is possible when we come together to transform the systems that harm us and our planet.

Earthjustice’s Toxic Exposure & Health Program uses the power of the law to ensure that all people have safe workplaces, neighborhoods, and schools; have access to safe drinking water and food; and live in homes that are free of hazardous chemicals.