First, Lynn Johnson’s grandfather, a farmer, was diagnosed with Parkinson’s disease. Then she got her own diagnosis, at 45. After that, her mother was diagnosed, too.

Johnson, 60, said that nobody in her family is genetically prone to the disease, which can spur tremors, instability, rigid or slow movements and cognitive effects like depression. She suspects that an environmental cause spurred her illness.

“I had to stop working, and my husband’s retiring soon because he feels like he needs to take care of me,” Johnson said at a news conference on Wednesday, March 11.

Surrounded by several other Parkinson’s patients, including members of a boxing club she joined to maintain strength and coordination, Johnson and others urged Minnesota lawmakers to ban paraquat, a herbicide that has been linked with the complex neurological disease.

A bill authored by DFL state Rep. Brad Tabke of Shakopee would do just that, adding Minnesota to a list of at least 13 other states considering similar legislation. This effort is a key initiative of the Michael J. Fox Foundation for Parkinson’s Research.

The Minnesota bill would bar the sales of paraquat starting in 2027 and use in 2028. The Minnesota Department of Agriculture would be responsible for collecting and destroying anything left over after the deadline. The chief sponsor of the Senate version is DFL Sen. John Hoffman of Champlin.

“We know paraquat is one of the contributors (to Parkinson’s),” Tabke said in an interview. “It’s very seldom used in Minnesota.”

Tabke said the legislation is aimed at reducing how many Minnesotans are diagnosed with Parkinson’s in the future. But some agricultural organizations, including one that represents the sellers of pesticides and fertilizers, say paraquat is an important tool for farmers implementing soil-saving practices like cover crops.

The state Department of Agriculture has not taken a formal position on the bill, but in the House committee hearing on Wednesday, Commissioner Thom Petersen said, “I’m not always 100 percent sure on bans, because what is the other product, then, that folks are going to use?”

Paraquat is already known as an acutely toxic chemical, with the Environmental Protection Agency warning that one sip of it can kill an adult. But a growing body of research in the past three decades has pointed to paraquat exposure as one of several factors that can increase the chance of Parkinson’s.

A 2024 study in California’s Central Valley found repeated, long-term exposure to paraquat for farmworkers doubled their likelihood of the disease, and elevated chances for neighbors within 500 meters of a spray.

More than 70 countries around the world have banned the chemical, though the EPA has not removed it from U.S. markets. The agency said last year it would ask manufacturers for more data on how far the chemical drifts. Current regulations restrict it from being sprayed around homes, parks or golf courses, and only those with a special license to apply it can purchase paraquat.

“The EPA’s argument ... of safety has been entirely built on the idea that it doesn’t drift,” said Dan Feehan, chief policy and government affairs officer for the Michael J. Fox Foundation. He said research in California has shown that the chemical does drift from the area it is sprayed.

Feehan noted that there is precedent for local action first. Multiple states banned the insecticide DDT before EPA barred it from most uses in 1972.

Some argue paraquat is still needed on farms. In a House Agriculture Committee hearing later on Wednesday, Tim Braun, a farmer and agronomist near Princeton, Minn., said paraquat was a crucial tool for farmers who are growing cover crops. Growers may use the broad-spectrum herbicide to kill off the radishes, turnips or winter rye planted to protect soil before spring planting.

Lee Helgen, executive director of the pesticide seller industry group Minnesota Crop Production Retailers, said some farmers may also want to keep paraquat around to battle herbicide-resistant weeds like palmer amaranth, which is starting to appear in southern Minnesota.

Paraquat’s use is rising as more people implement cover crops. According to the Agriculture Department, 125,000 pounds were sold in Minnesota in 2024, double the previous year.

Still, the chemical is niche compared to other herbicides. By contrast, 16.3 million pounds of glyphosate, the active ingredient in Roundup, were sold in the state in 2024.

Tabke is hopeful the bill will pass this session, even though an even-party split in the House makes that goal more difficult. In the Senate, Republican Jim Abeler of Anoka is a co-sponsor of the bill.

Meanwhile, the Parkinson’s patients who are advocating for the ban said they want to help others avoid their condition.

Having Parkinson’s, Johnson said, is “a process of grieving every day because you lose something you used to be able to do. ... If we can prevent this so no one else has to keep losing, it’s worth it.”

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