Editor's note: This story follows Environmental Protection Agency guidance and uses pesticide as an umbrella term for substances that control pests.
Earlier this month, a second Wyoming man filed a federal lawsuit against the agribusiness giant, Monsanto. It’s one of more than 18,000 lawsuits claiming the world’s most widely used pesticide causes cancer and that Monsanto has tried to cover up the risks. Reports that some agricultural experts in Montana are concerned that growing public scrutiny could affect trade and take away a tool for farmers. Others say they’re already losing that tool as weeds become more resistant.
Near the town of Vida in northeast Montana, Trevor Schock is driving around the 10,000 acres he farms with his dad and a hired-hand. It’s the end of August and an immense blue sky presses down on the patchwork of brown, yellow and golden fields.
Schock points out a harvested field where they sprayed weed killer two days ago.
“So you can see the weeds are already starting. They don’t have a deep green color. They’ve got more of a limey-going-on yellow color. The edges are starting to burn up a bit,” Schock says.
Like many farmers, Schock rotates fields in and out of production to give the soil a rest and let it absorb more moisture. But he says there’s a tradeoff.
By letting a field go fallow for a year, Schock says weeds can take over.
“You can either till it, you know, disturb the ground and rip it up, which has kind of been shown to be not the greatest thing for the soils, or you can spray chemicals on it. Glyphosate would be the primary chemical we use for that,” Schock says.
Farmers have been using glyphosate for the last four decades, primarily in the form of Monsanto’s signature product: Roundup. It’s fairly cheap and industry experts consider it safer than some other pesticides on the market. But over the last five years, it has become part of a contentious debate in courtrooms and international trade.
In 2015, an arm of the World Health Organization classified glyphosate as “probably carcinogenic to humans.” It sparked thousands of lawsuits from people with non-Hodgkin lymphoma who'd used Roundup and Monsanto has had to pay millions of dollars in damages for three civil cases.
Following the WHO report, the U.S. Environmental Protection Agency and the European Food Safety Authority decided to review glyphosate again. But they concluded glyphosate is “not likely to be carcinogenic.”
“We need to stick to the old adage that the dose makes the poison,” says Cecil Tharp, Montana State University’s Extension Pesticide Education Specialist.
“There has been a few studies that did show glyphosate maybe associated with non-Hodgkin lymphoma, but when looked at closer, these associations were quite weak. Most studies did not find these associations,” Tharp says.
He says when WHO classified glyphosate as a probable carcinogen, it wasn’t quantifying the concentration it would take to cause cancer whereas the EPA does. For example, the WHO puts glyphosate in the same category as red meat. Why? Because there are associations between eating red meat and colon cancer. That doesn’t mean a vegetarian who eats a steak will automatically get cancer.
But there are other complications that have made it hard for people to trust glyphosate.
In the EPA’s re-evaluation of the chemical, the agency looked at evidence from some private studies that were paid for by Monsanto. During a court case in 2017, internal company emails showed how Monsanto tried to recruit outside scientists and reporters to defend the safety of glyphosate and discredit WHO.
At the same time the Environmental Working Group released test results in 2018 showing glyphosate residues in Cheerios and other popular cereals and snacks.
The news resulted in a big public backlash.
Pesticide Education Specialist Cecil Tharp says whether or not something causes cancer, public opinion matters. Some of the European markets that import American grain are even more suspicious of glyphosate.
“There is increased scrutiny on glyphosate, now that’s a fact and it’s changing the markets somewhat where foreign markets now are testing for glyphosate residual at a much higher incidence,” Tharp says.
Glyphosate testing isn’t required in the U.S. unless the grains are organic or headed to a foreign market. Ben Thomas is the director of the Montana Department of Agriculture.
“When it comes to other countries, that’s largely a partnership of private testing facilities and the countries themselves,” Thomas says.
Thomas says there are international limits for glyphosate residues on food products, but some countries have started adopting their own standards. Last year, Italy cut back on imports of Canadian wheat because it had trace amounts of glyphosate.
“The bottom line is it’s going to be disruptive to trade. So as we see these levels being set differently in a manner that’s not based on science; it’s not based on protecting human health, it’s going to limit our options for exporting,” Thomas says.
He says he’s concerned increasing public pressure could also take away an important tool farmers use to manage weeds.
Back at the farm near Vida, Trevor Schock points out some more weeds.
“Probably within the last ten years, we’ve been noticing that glyphosate resistant weeds are becoming more and more of a thing. Kosha in particular, and then, it seems like the newer weeds, the [narrow leaf] hawksbeard and the mare’s tail, it kind of has a natural glyphosate resistance, especially when it’s larger,” Schock says.
The heaviest applications of glyphosate in the U.S. are in the Midwest, on fields where genetically modified corn and soybeans are being grown. In Montana, the pesticide is mostly used for killing weeds before crops are planted or after they’re harvested.
Schock says he and his neighbors recognize that they’ll have to find an alternative to pesticides with glyphosate in the future. Perhaps the weeds themselves will be a faster game-changer than changing market demands and regulations.