Twenty-one cereals and snack products commonly consumed by children contain the herbicide glyphosate, according to tests from the Environmental Working Group (EWG).

According to the activist group, the weedkiller, which is produced by Bayer-Monsanto, was found in all the products. All but four contained glyphosate levels higher than what EWG scientists consider safe. The recent study backs up findings from tests completed by the group in July and October last year.

The highest levels of glyphosate were found in Honey Nut Cheerios Medley Crunch (833 parts per billion) and Cheerios (729 ppb). The EWG’s benchmark for safe levels of glyphosate for children is 160 ppb. Glyphosate was also found in products such as Nature Valley crunchy granola bars and Fiber One oatmeal raisin soft-baked cookies. The US Environmental Protection Agency (EPA) has a higher safety threshold for glyphosate than EWG: between 0.1 and 310 parts per million, depending on the crop.

“Glyphosate is used mostly as a weedkiller on genetically modified corn and soybeans. But it is also sprayed on oats just before harvest as a drying agent, or desiccant. It kills the crop, drying it out so it can be harvested sooner, which increases the likelihood that glyphosate ends up in foods children love to eat,” EWG wrote in a Wednesday press release.

"The only way to quickly remove this cancer-causing weedkiller from foods marketed to children is for companies like General Mills and Quaker to use oats from farmers who do not use glyphosate as a desiccant," it added.

In March 2015, the International Agency for Research on Cancer, part of the World Health Organization, classified glyphosate as “probably carcinogenic to humans” (Group 2A). A couple years later in July 2017, the chemical was deemed a known carcinogen by California’s Office of Environmental Health Hazard Assessment.

“Since last August, three California juries have awarded more than $2.2 billion total in three separate verdicts against Bayer-Monsanto over claims that Roundup [an herbicide product containing glyphosate] caused cancer and that Monsanto knew about the risks for decades and went to extraordinary lengths to cover it up,” EWG wrote in its press release.