U.S. efforts to bully Mexico over its announced restrictions on imports of genetically-modified (GM) corn intensified last week, as a U.S. Trade Representative official gave the Mexican government less than a week “to explain the science behind Mexico’s planned bans on genetically modified corn and glyphosate herbicide,” according to Reuters.
In response, Mexico’s Minister of the Economy, Raquel Buenrostro, announced that the government is indeed revising its original December 2020 presidential decree to clarify the nature and scope of the restrictions, originally announced to take effect in January 2024. Sure enough, her ministry released the revised decree February 13. The new edict addresses many U.S. concerns, most importantly clarifying that any ban on GM feed corn, which is the overwhelming majority of U.S. exports, would only be implemented gradually, pending a full review of the science and the availability of adequate supplies of non-GM corn.
Don’t expect any thank-you notes from U.S. officials. Indeed, U.S. Agriculture Secretary Tom Vilsack was quick to snap the olive branch offered by Mexico. “USDA is disappointed in Mexico’s new decree regarding genetically modified corn.” Trade officials told Inside US Trade that USTR does not consider the decree a “formal response” to its questions on the science.
So fasten your seatbelts for another bumpy ride through the highly polarized debates over what constitutes “sound science” and over what levels of precaution governments should be allowed to take in the face of scientific uncertainty. To U.S. industry and government officials, precaution is a dirty word.
As a public service, I offer here some of the scientific evidence justifying Mexico’s restrictions on GM corn and glyphosate. It is a small sample from a large and still-growing literature.
GM Corn restrictions are intended to promote the health of people and the climate.
Mexico’s proposed GM corn restrictions are part of a larger effort by the government of Andrés Manuel López Obrador, swept into power in a 2018 landslide, to better protect public health and the environment. The three-year phaseout of glyphosate, the herbicide in Bayer/Monsanto’s Roundup products, is just one of a range of toxic pesticides being banned as part of a sweeping public health law now making its way through the legislature. The glyphosate phaseout is reiterated in the new decree with a deadline of March 2024, and usage has declined steadily in the last two years. The government has also taken bold action to address Mexico’s alarming rise in obesity and non-communicable diet-related diseases, enacting a strong labeling requirement for foods high in salt, fats, and sugars.
Environmental initiatives include the promotion of agroforestry and agroecology and protection of Mexico’s unique diversity of corn varieties from cross-pollination by GM corn. The revised decree, which applies only to corn, not other GM crops does the following:
It reiterates the immediate ban on the cultivation of GM corn to prevent cross-pollination, in line with the court-ordered injunction in place since 2013.
The revisions clarify that there is no ban on the importation of U.S. GM white corn, but there is an immediate prohibition on the use of any GM corn in products for “direct human consumption,” clearly defined as the tortilla and corn flour supply chain. Enforcement will focus on producers of those products, and the decree calls for measures to ensure traceability, an important step.
The decree also reiterates that government agencies will cease all purchases of GM corn and glyphosate.
It eliminates the 2024 deadline for the phaseout of GM corn imports for animal feed and industrial uses, but it keeps in place the intention to substitute domestic non-GM corn over time, which aligns with government plans to increase food self-sufficiency.
It establishes Mexico’s Federal Commission for Protection Against Sanitary Risks (COFEPRIS, by its Spanish acronym) as the agency responsible for assessing risk and approving future import licenses requested by U.S. exporters. Implied in the decree is the right to enforce the government’s preference for non-GMO corn for future uses.
It calls for further study, in conjunction with North American partners, of the risks to human health and the environment from GM feed corn.
The decree commits to science-based decisions in compliance with the United States-Mexico-Canada (USMCA) trade agreement. In Buenrostro’s words, “If they prove that there is no harm to health, then it will be approved.”
And the new decree makes clear that Mexico reserves the right to take precautionary measures it considers important to protect public health and the environment, including the genetic integrity of its rich diversity of native corn.
Science evidence makes the case for precautionary measures.
U.S. industry representatives and government officials have repeatedly insisted that Mexico’s actions are not based on science. As always, U.S. leaders insist that they get to determine what constitutes “sound science,” despite the atrocious record of poor public health protections by U.S. regulations heavily influenced by industry. But Mexico does indeed have science on its side.
In fact, Mexico’s highest government science body has published a database on glyphosate and GM corn with 28 pages of citations. If fact it is so large that it is difficult to navigate. U.S. officials could examine that scientific evidence, which has been available since the 2020 decree. But to make it easier for them, let’s highlight some of the most important evidence.
In the U.S., which has allowed unlabeled GM corn to enter the food supply since the mid-1990s, the mantra is that no one has been harmed, regulators have adequately tested the new products, and there is a scientific consensus on the safety of eating GM foods. Many scientists beg to differ, as I wrote in an earlier Food Tank article, arguing that scientific uncertainty justifies precautionary restrictions because evidence of harm, mainly from animal studies, has not been taken seriously nor been followed up to assess the risks to human health. Below is some of the key evidence.
A 2015 statement signed by more than 300 scientists insisted that there is no scientific consensus on GMO safety: “the scarcity and contradictory nature of the scientific evidence published to date prevents conclusive claims of safety, or of lack of safety, of GMOs.”
My late Tufts University colleague, Sheldon Krimsky, conducted broad reviews of the academic literature in 2018 and reported “An Illusory Consensus Behind GMO Health Assessment. He found 26 studies that “reported adverse effects or uncertainties of GMOs fed to animals;” eight other literature reviews that showed anything but a consensus on safety; and no consensus among medical and scientific associations. All are listed in his extensive bibliography. (I summarize his findings in this earlier Food Tank article.)
A 2017 peer-reviewed study reported the “Pervasive Presence of Transgenes and Glyphosate in Maize-Derived Food in Mexico,” which raised alarms about the integrity of Mexico’s food supply even when GM corn was not being grown in the country.
Many scientists have also pointed out that evidence from the U.S. experience is of limited value because Mexico’s high levels of direct consumption of minimally processed corn products, such as tortillas, presents levels of risk that make U.S. exposures a poor guide to risk. As expert Charles Benbrook recently told me, “There is inadequate data to conduct an assessment of the impacts of Bt corn on the GI tracts of people consuming corn-based foods. The studies have still not been done.” This is known as “undone science” – investigations not carried out due to vested interests.
While most of the current controversy has focused on concerns about human health, Mexico’s decree also cites the threat to the genetic integrity of the country’s megadiverse native corn due to uncontrolled cross-pollination from GM corn planted in nearby fields. Such risks were the basis for the successful challenge to permits issued by Mexico’s previous administrations for cultivation of GM corn, a citizen lawsuit I document in my excerpted book chapter, “Monsanto Invades Corn’s Garden of Eden in Mexico.”
I interviewed many scientists about the risks of “gene flow,” but we can look to NAFTA itself for the definitive science. NAFTA’s own Commission for Environmental Cooperation in 2003 conducted a trinational expert assessment of the risks to native corn biodiversity from GM corn. The scientific findings in “Maize and Biodiversity: The Effects of Transgenic Maize in Mexico” are still relevant today.
Open pollination can result in gene flow to nearby fields of native corn, and the pollen can travel much further than previously believed. (A later study showed transgenes present in native corn varieties in 14 Mexican states).
The contamination that prompted the study likely came from GM corn imported from the United States, unlabeled, distributed as food through a Mexican government agency, then unknowingly planted by a farmer. (That could easily happen again, which is why Mexico’s decree calls for traceability of imported GM corn).
Transgenes can spread further through subsequent pollination, threatening native corn diversity, which is invaluable culturally, environmentally, and also economically for future crop breeding.
Precautionary policies are warranted, including policies to restrict the importation of corn in kernel form from the U.S., which does not identify GM content through labeling.
U.S. trade officials have not directly challenged Mexico’s glyphosate phaseout, but there is no shortage of scientific evidence to justify the ban.
The World Health Organization (WHO) finds that Roundup herbicides are a “probable human carcinogen,” which I covered in an earlier Food Tank article. The WHO findings are summarized in an accessible two-page monograph and in The Lancet Oncology.
According to Forbes, Bayer/Monsanto has settled more than 100,000 lawsuits charging the company with misleading consumers about the safety of Roundup, and another 30,000 lawsuits are pending.
Damaging evidence keeps mounting. One recent study showed negative health impacts downstream from farms heavily using glyphosate, while the Guardian reported that 60 percent of urine samples in the U.S. showed traces of glyphosate and higher levels of “oxidative stress,” which is associated with cancer risk.
As I have previously reported, there is nothing in the new Agricultural Biotechnology section of the USMCA that obligates any country to approve a GM crop approved in another country. Nor does it mandate that the three countries must accept other countries’ scientific assessments nor calculations of risk. It mandates transparency, consultation, and science-based decision-making. That seems to be exactly what the Mexican government is offering the U.S. with its revision of the 2020 presidential decree.
Mexico retains the right to take precautionary measures it deems necessary to protect public health and the environment. Precaution may be a dirty word for U.S. regulators, but not a U.S. public wary of industry lies about the dangers of its products – tobacco, fossil fuels, lead, asbestos, DDT, and PCBs, just to name a few. (See “Late Lessons from Early Warnings” for a longer list of such cases). Rather than challenge Mexico’s health and environmental policies, perhaps we can learn something from them.
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