Favorite oat cereals, oatmeal, granola, and snack bars come with a hefty dose of the weed-killing poison in Roundup, according to independent laboratory tests commissioned by environmental health NGO Environmental Working Group, released on August 15.

Glyphosate, an herbicide linked to cancer by California state scientists and the World Health Organization, was found in all but two of 45 samples of products made with conventionally grown oats. Almost three-fourths of those samples had glyphosate levels higher than what EWG scientists consider protective of children’s health with an adequate margin of safety.

About one-third of 16 samples made with organically grown oats also had glyphosate, all at levels well below EWG’s health benchmark, said Alex Temkin, Ph.D., a toxicologist at EWG.

Glyphosate is the active ingredient in Roundup, the Monsanto weed killer that is the most heavily used pesticide in the U.S. In August this year, a California jury ordered Monsanto to pay $289 million in damages to a man dying of cancer, which he says was caused by his repeated exposure to large quantities of Roundup and other glyphosate-based weed killers while working as a school groundskeeper.

EWG tested more than a dozen brands of oat-based foods to give Americans information about dietary exposures that government regulators are keeping secret. In April, internal emails obtained by the nonprofit US Right to Know revealed that the Food and Drug Administration has been testing food for glyphosate for two years and has found “a fair amount,” but the FDA has not released its findings.

Each year, more than 250 million pounds of glyphosate are sprayed on American crops, primarily on “Roundup-ready” corn and soybeans genetically engineered to withstand the herbicide. But when it comes to the food we eat; the highest glyphosate levels are not found in products made with GMO corn.

Increasingly, glyphosate is also sprayed just before harvest on wheat, barley, oats and beans that are not genetically engineered. Glyphosate kills the crop, drying it out so that it can be harvested sooner than if the plant were allowed to die naturally.

Roundup was produced for decades by Monsanto, which this year merged with the German pharmaceutical company Bayer AG. In the case decided this summer, the jury found that Monsanto knew for decades of the product’s hazards and not only failed to warn customers but schemed to discredit the evidence publicly.

The California case is the first of reportedly thousands of lawsuits against Monsanto. These suits have been brought by farm workers and others who allege that they developed cancer from years of exposure to Roundup.

In 2015, the International Agency for Research on Cancer, part of the World Health Organization, reviewed extensive U.S., Canadian and Swedish epidemiological studies on glyphosate’s human health effects, as well as research on laboratory animals. The IARC classified the chemical as probably carcinogenic to humans and has steadfastly defended that decision despite ongoing attacks by Monsanto.
In 2017, California listed glyphosate in its Proposition 65 registry of chemicals known to cause cancer.

The state’s Office of Environmental Health Hazard Assessment, or OEHHA, has proposed a so-called No Significant Risk Level for glyphosate of 1.1 milligrams per day for an average adult of about 154 pounds. That level of exposure is more than 60 times lower than the safety level set by the Environmental Protection Agency.