Parkinson’s concerns push paraquat out of Vermont

Vermont has become the first US state to ban paraquat, one of the world's most widely used herbicides, with lawmakers citing concerns over a possible link between the weedkiller and Parkinson’s disease.

The ban has been warmly welcomed by campaigners, who hope Vermont's decision will encourage other states to follow suit in an effort to curb a neurological disease that gradually deprives people of control over their movements and affects around one million Americans.

“Vermont took the step to be the leader in this, and that’s significant because it shifts the conversation,” said Dan Feehan of The Michael J. Fox Foundation, the world’s largest non-profit funder of Parkinson’s research. “Now, the question becomes: ‘Will your state be the last to ban it?’”

For some farmers, however, the measure could place further pressure on already narrow profit margins. Efforts to restrict paraquat in other states, where the herbicide is used more extensively, have repeatedly failed to gain traction.

The US Environmental Protection Agency (EPA) is currently reviewing the safety of paraquat, having previously stated that there is no clear evidence linking the herbicide to Parkinson’s disease.

Syngenta, the Swiss agrochemicals company that has manufactured paraquat for decades, announced earlier this year that it would cease global production and sales of the chemical. Nevertheless, the company continues to defend the product’s safety, and paraquat remains available through other manufacturers.

“Despite decades of investigation and more than 1,200 epidemiological and laboratory studies of paraquat, no scientist or doctor has ever concluded in a peer-reviewed scientific analysis that paraquat causes Parkinson’s disease,” Syngenta said.

Widely used in the US, banned elsewhere

First introduced in the United States in 1964, paraquat quickly became a popular weedkiller among farmers.

The chemical is highly toxic and can be fatal if swallowed. Contact exposure can also cause chronic health problems. Farmworkers are particularly vulnerable, prompting the EPA to require specialised training for certified paraquat applicators. The training, which takes roughly an hour to complete, includes a 15-question assessment and must be renewed every three years.

According to the United States Geological Survey (USGS), paraquat is commonly used to protect soybean, cotton and maize crops, as well as apples and grapes. In 2018 alone, more than 10 million pounds (4.5 million kilograms) of paraquat were applied across the US, with usage concentrated largely in the South, Midwest and California.

Despite its widespread use in America, dozens of countries have prohibited the herbicide. The European Union and the UK banned paraquat in 2007. China prohibited its domestic use in 2017, while Vietnam and Malaysia introduced similar restrictions. Thailand followed with a ban in 2019.

Health concerns and the Parkinson’s debate

Supporters of paraquat argue that the herbicide is rapidly absorbed by weeds, meaning rainfall shortly after application is unlikely to wash it into the soil. Companies such as Syngenta also maintain that paraquat becomes immobilised once it comes into contact with soil.

However, concerns remain over its potential health effects. Parkinson’s advocates argue that people living near areas where paraquat is sprayed face an increased risk of developing the disease.

The question of whether paraquat causes Parkinson’s has been the subject of intense scientific debate and research for many years.

Dr Philip Landrigan, an epidemiologist who directs a global health programme at Boston College and has long campaigned against exposure to toxic chemicals, said multiple studies suggest environmental factors — including exposure to pesticides such as paraquat — can increase the risk of Parkinson’s disease.

For many within the Parkinson’s community, Vermont’s decision represents a major breakthrough.

“No matter how you slice and dice it, there’s no safe way to use paraquat,” said Ron McConnell, a Vermont resident diagnosed with Parkinson’s after being exposed to a different toxic substance at work in 2017. “This law that Vermont just passed is protecting both the farmers who use it and the farmworkers who handle it.”

The ban will take effect on 1 November. However, farmers who use paraquat on fruit orchards, berry farms and small-fruit crops will have until 2030 to transition away from the herbicide.

Farmers prepare for life without paraquat

Greg Burtt, a Republican Vermont lawmaker and owner of a family-run apple orchard, describes paraquat as a “critical tool” in his farming operation.

He believes the ban will leave growers such as himself at a competitive disadvantage compared with farmers in states where the herbicide remains legal and comparatively inexpensive.

While alternative herbicides are available, some farmers argue that they can damage crops if not applied carefully. Other options, including mechanical tilling, crop rotation and manual weeding, are also available but often involve significantly higher labour costs.

“There’s a reason why it’s an industry standard,” said Burtt, who has used paraquat for two decades.

He remains unconvinced by claims that paraquat causes Parkinson’s disease, saying he finds the scientific evidence inconclusive.

“I want to be the first person to make sure that it’s safe because I don’t want to die young because of farming,” Burtt said. “If anyone has had to wrestle with these questions, it’s me.”