Many best sellers in the cereal aisle continue to have trace amounts of the weed killer glyphosate, according to a new report published Wednesday by the Environmental Working Group (EWG).

The herbicide was detected in all 21 oat-based products. All but four of them contained levels of glyphosate higher than what EWG scientists deem safe for children.

This is the third round of glyphosate tests by EWG, which receives funding from organic food companies, according to its own disclosures.

The new round confirms the findings from the first two tests in August and October last year. Tests of 94 samples of oat-based foods found glyphosate in all but two samples, with 74 samples at levels of glyphosate above EWG's health benchmark.

In this latest analysis, the highest levels of the weedkiller were detected in General Mills' Honey Nut Cheerios Medley Crunch at 833 parts per billion, or ppb, and Cheerios, with 729 ppb. EWG's health benchmark for children is 160 ppb. EWG says a child would only need to eat a single 60-gram serving of food with a glyphosate level of 160 ppb to reach the maximum dose it considers safe, according to a press release.

"As these latest tests show, a box of Cheerios or other oat-based foods on store shelves today almost certainly comes with a dose of a cancer-causing weedkiller," said Olga Naidenko, Ph.D., vice president for science investigations at EWG, said in an EWG press release.

The manufacturers insist their products are safe and that EWG's findings are unprecedented, according to CNN. And, before cutting your kid's carbs, it's worth noting that no case of cancer has ever been linked to eating breakfast cereal. EWG's study was never submitted to peer review nor were they published in a scientific journal. And, EWG created its own standard of toxicity, as it explains on its website. Its standard of toxicity for glyphosate exposure is about 1/100th of the California threshold, which is about 1/100th of the U.S. Environmental Protection Agency's (EPA) standard. In other words, EWG's limit for consuming glyphosate hovers around 1/10,000th of what the EPA deems as safe, according to Slate.

"It is not surprising that very low levels of pesticides, including glyphosate, are found in foodstuff," said Dr. Paolo Boffetta, associate director for population sciences at Mount Sinai's Tisch Cancer Institute, as reported by CNN. "In general, these levels are unlikely to cause health effects in consumers."

The latest findings come on the heels of three civil cases in California that have ordered Bayer AG, Monsanto's parent company, to pay more than $2.2 billion in damages for cancer caused by exposure to Roundup. Thousands more lawsuits have been filed, according to CNN, which has caused investors to flee Bayer. Its share price is half of its 52-week high.

Glyphosate's toxicity has been at the center of controversy since 2015 when the International Agency for Research on Cancer, a part of the World Health Organization, classified it as "probably carcinogenic to humans." Then, in 2017, glyphosate was classified as a known carcinogen by California's Office of Environmental Health Hazard Assessment.

"Does General Mills really want to keep using a chemical that independent scientists say causes cancer, made by a company that three juries have found guilty of covering up its health hazards?" Naidenko said in EWG's press release. "Or will they listen to the growing chorus of concerned consumers calling on General Mills and other companies to remove glyphosate from the cereals kids love to eat?"

Sentiments similar to Naidenko's that tarnish Roundup in the court of public opinion combined with the recent spate of legal action and legislation targeted at glyphosate prompted the EPA to reaffirm its stance that the herbicide poses no risk to public health, according to the Associated Press.