Mexico smacks US over GM corn and glyphosate

A Mexican standoff with the United States turned into a Mexican smack-down this month with the release of Mexico’s formal rebuttal to US efforts to overturn limits Mexico has ordered on the use of genetically modified (GM) corn and the weed killing chemical glyphosate.

In a 189-page report filed with a panel of the United States-Mexico-Canada Agreement (USMCA), Mexico laid out in stark terms why it has ordered that GM corn not be used for tortillas and dough that people eat and why it has ordered its farmers to stop using glyphosate.

“Mexico has legitimate concerns about the safety and innocuousness of genetically modified corn… and its indissoluble relationship with its technological package that includes glyphosate,” the government’s report states. Mexico cites the “use of dangerous pesticides” as a factor causing “serious health effects.”

There is “clear scientific evidence of the harmful effects of direct consumption of GM corn grain in corn flour, dough, tortilla and related products,” Mexico states. More evidence is needed, Mexico says, to determine “whether and to what extent, such risks are transmitted to food products further downstream…”

The moves are for the “purpose of contributing to food security and sovereignty” and “the health of Mexican men and women”, the Mexican government said when announcing the moves.

The US has asserted that Mexico is not basing its decision on science and is violating agreements under the USMCA trade pact. The battle has intensified over the last year and in its latest response, Mexico didn’t just reject the US arguments, but laid out in detail a wealth of scientific research that backs its concerns.

It is the US, not Mexico, that is failing to follow the science, the Mexican government says.

“The United States alleges that the challenged measures are not based on science, but seeks to prove its arguments with publications without the minimum scientific rigor, outdated, or, if applicable, with an evident conflict of interest,” the Mexican response states.

Glyphosate is the active ingredient in the Roundup herbicide brand launched decades ago by Monsanto and now owned by Bayer, which bought Monsanto in 2018. Monsanto developed genetically engineered corn, soybeans, canola and other crops to tolerate being sprayed with glyphosate, a trait that allows farmers to spray the pesticide over the tops of growing crops without killing them, while killing weeds.

Opposition to glyphosate and to crops sprayed with it has escalated over the years, particularly after the World Health Organization’s International Agency for Research on Cancer classified glyphosate as a probable human carcinogen in 2015 based on published and peer-reviewed scientific research.

Foods made with crops sprayed with glyphosate commonly carry residues of the weed killer, which people then consume through their daily diets. In addition to being engineered to withstand being sprayed with glyphosate, most US corn is engineered to make its own toxins to protect it from certain pests.

In addition to citing health concerns associated with GM corn, Mexico says it considers GM corn a threat to native varieties that could negatively impact Mexico’s biodiversity.

Mexico cites evidence of risk

An analysis of the Mexico report finds 13 pages of evidence, including 66 references to peer-reviewed academic work, that GM corn, particularly insect-resistant “Bt” varieties, pose potential health risks to people through damages to the intestinal tract and other organs, according to Timothy Wise, senior research fellow at Tufts University and senior advisor on the Future of Food at the Institute for Agriculture and Trade Policy.

Additionally, the report includes 74 academic references to support Mexico’s concerns about risks to Mexican consumers from glyphosate residues on GM corn, Wise said. He pointed out that most studies cited by supporters of GM crops and glyphosate as proof of safety are studies paid for by the companies selling the crops and chemicals, with many not even peer-reviewed.

“Mexico has shown that it has the latest independent science firmly on its side,” Wise said. “Mexico highlights that the US cannot produce a single academic study that shows that the long-term consumption of large quantities of minimally processed GM corn treated with glyphosate is safe to eat,” said Wise.

In comments submitted to the USMCA Secretariat on March 13, the nonprofit Friends of the Earth (FOE) organization also said the science favors Mexico’s position.

Glyphosate has been linked in research to fatty liver disease and kidney damage, among other health problems, the group notes. And when it comes to research on GM corn, there is a severe lack of evidence showing safety, according to FOE.

Current versions of GM corn can carry multiple toxins engineered into them to fight pests as well as residues of the herbicides sprayed on corn. But there has been no comprehensive research aimed at assessing human health risks stemming from exposure to the toxins and chemicals, FOE states.

“Rising reliance on pesticides and toxins in corn production has diversified the routes and levels of human exposure to both. Despite the absence of the data and knowledge needed for a full accounting, this increase has surely led to new and more serious adverse impacts on human health and the environment,” FOE said in its submission.

Yet, the “scope and adequacy of scientific research and regulatory oversight” of GM corn human health impacts” has receded in the wake of persistent political pressure for ‘regulatory relief,’” the group states.

Industry influence

The US government’s actions aimed at blocking Mexico from putting limits on glyphosate and GM corn have come largely at the behest of industry, including Bayer, Corteva AgriScience (a company created from the former Dow and DuPont companies), lobbyist CropLife America, the Corn Refiners Association, and other industry actors.

The industry efforts have been revealed in internal government emails obtained through Freedom of Information Act requests by the Center for Biological Diversity. 

The center is one of dozens of organizations demanding that US officials respect Mexico’s sovereignty and stop trying to block Mexico’s policies on pesticides and GM crops.

The pressure on Mexico is similar to actions chemical industry lobbyists took to kill a glyphosate ban planned by Thailand in 2019. Thailand officials had also cited concerns for public health in seeking to ban the weedkiller, but reversed course after US threats about trade disruption.