Dan Charles / NPR
John Draper and I sit in the cab of a tractor on the research mass he manages for the University of Maryland, next to Chesapeake Bay. Behind us there is a syringe.
"So, away we go!" Draper says. He pushes a button and we start moving. A fine mist comes out of nozzles on the syringe's arms.
We spray glyphosate and kill off this field's tillage "crop crops" of rye before planting soybeans.
Farmers have often used this chemical under the Roundup brand for about four decades now.
But now it is under severe attack, accused of causing cancer. In three civil cases so far, US juries have ordered Roundup's inventor, Monsanto, now owned by Bayer, to pay huge damage to cancer survivors. Thousands more court cases have been filed.
For this chemical, and for Monsanto, there is a wonderful change in fortunes.
Farmers felt that they could spray glyphosate with good conscience. It does not persist in the environment as much as it says DDT did. It does not build up in groundwater as another used herbicide, atrazine. And it is certainly less toxic than some alternatives.
"If we spray Gramoxone [the trade name for paraquat, another herbicide] even if you are standing next to the syringe, you need a respirator. I have to wear a respirator, even in the tractor, spraying," says Draper.
Monsanto began selling Roundup in 1974. For 20 years there was not much attention. There was law 1 of the glyphosate drama: the silent years.
Act 2 began in the late 1990s.
In 1996, Monsanto began selling genetically modified crops or GMOs. They were modified to tolerate glyphosate. This meant that the farmers could now spray this chemical just above their "Roundup Ready" soybeans, corn and cotton, and the crop would be good, but the weeds would all die.
There was a farming revolution built on glyphosate. Monsanto quickly became the world's largest seed company. And the farmers started spraying much more roundup. Sales of the chemical increased more than ten times.
It all happened so fast that it scared many people. There were anti-GMO protests around the world, and glyphosate came under increasing scrutiny.
The International Agency for Cancer Research, part of the World Health Organization, decided to re-evaluate glyphosate risk.
On March 20, 2015, IARC announced its conclusion: Glyphosate is "probably carcinogenic to humans."
This conclusion rests on three types of studies. First, IARC found "strong evidence" that glyphosate can damage DNA in cells. This type of injury, inducing mutations, is the first step in causing cancer. Secondly, studies show that when mice ate glyphosate, they had multiple tumors. Kate Guyton, a senior toxicologist at the IARC, told reporters at a press conference that "these two studies provided sufficient evidence of animal cancer."
Finally, the IARC says that there is "limited evidence" that people exposed to glyphosate had higher frequencies of a particular type of cancer – non-Hodgkin's lymphoma.
Guyton has been studying the causes of cancer for decades. Nothing she's ever done, she says, provoked so much of a reaction like the glyphosate message. "The internet type exploded," she says.
Anti-GMO groups felt corrected. Monsanto's top leaders were furious and launched a promotional campaign that attacks the IARC and its report.
And in the small town of Orange, Va, a personal injury lawyer, Michael Miller, began to anchor clients – people with non-Hodgkin's lymphoma that I used Roundup. "I decided that these people needed a voice in the courtroom," he says.
However, the scientific image became more complicated. Other authorities, including the US Environmental Protection Agency and the European Food Safety Authority, took a new look at glyphosate. And they concluded that probably is not that gives humans cancer.
David Eastmond, a toxicologist from the University of California, Riverside, helped carry out one of these glyphosate speech for another part of the World Health Organization, the joint FAO / WHO pesticide residue meeting.
"From my reading of things, if glyphosate causes cancer, it's a pretty weak carcinogen, which means you need quite high doses in order to cause it," he says.
Eastmond says there are several reasons why this apparent disagreement between the IARC and the other agencies.
First, the IARC only looks at whether glyphosate can cause cancer; 19659008] Second – and most important, according to Eastmond – considered various bodies for various evidence. Eastmond's selection and regulatory bodies such as EPA considered a large number of non-publicly available studies because Monsanto paid for them and sent them to the agencies. "I've never seen a chemical with so many animal cancer studies as glyphosate, "says Eastmond.
However, the IARC did not make the most of this study because it only accepts publicly available studies This allows any other researcher to see exactly what IARC conclusions are based on.
Eastmond believes for its part that company-funded studies are credible and valuable, despite potential conflict of interest for companies performing these studies. Labs, he says, must adhere to strict guidelines.
Finally, the researchers sometimes see the same data and disagree on what it means. Eastmond says he and Guyton had "animated discussions" about some of the data. "We have just considered the evidence differently, but you know, there are honest disagreements [among] people I think are well-meaning," says Eastmond.
Then the Act 3 arrived. Glyphosate went to court. There were three civilian trials in or near San Francisco.
Lawyers for Bayer, who now own Monsanto, repeated repeated lawyers that regulatory bodies had concluded that glyphosate is not a cancer risk.
Lawyers for the cancer victims, suggested that the same regulators could not trust because they had been manipulated or tricked by Monsanto.
Miller and his legal team showed the jury a whole collection of internal Monsanto emails. In one, corporate executives described telephone conversations with an EPA official. As Miller describes it, the official said, "I don't need to see any more studies. I'll declare Roundup safe, and I'll stop another agency from looking at it."
Another Monsanto executive discussed ghostwriting papers on glyphosate security that researchers can publish under their own names.
"I think the jury was legally offended," Miller says.
All three trials ended with resounding values in favor of cancer victims. The jury ordered Bayer to pay large penalties. In the latter case, the compensation amounted to $ 2 billion.
Bayer appeals to these verdicts – and the damage is likely to be reduced. But several court cases are waiting. The total value of Bayer's share has fallen $ 40 billion since the first verdict was announced.
Alexandra Lahav, a professor at the University of Connecticut School of Law, says that a lesson in this matter so far is that attempts to make favorable decisions by lawmakers can come back to court.
"They open up to the jury to say," Wait a minute – you're trying to convince the regulator not to regulate you, and now you want me to believe that the regulator is completely objective, Lahav says.
When regulators are seen as weak or ineffective guard dog, she says that their letter of approval also carries less weight with the audience – and with juries.
Next glyphosate trial is set to August in St. Louis.