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PITTSBURGH (KDKA/CBS) — An environmental group says more than two dozen oat-based cereals and snack bars tested positive for a weed-killing chemical.

The Environmental Working Group (EWG) has been investigating oat-based cereals and snack bars that contain glyphosate, a weed-killing chemical that some health authorities link to cancer.

They published the results of their second round of testing Wednesday.

The organization tested 10 samples of different types of General Mills’ Cheerios and 18 samples of different Quaker brand products, including instant oatmeal, breakfast cereal and snack bars.

They say 26 out of 28 samples tested had higher levels of glyphosate than what EWG scientists concern protective of children’s health.

In an email to CBS MoneyWatch, General Mills said “trace amounts [of glyphosate] are found in the majority of food we all eat” since most crops are grown in fields that use some sort of pesticides.

“The extremely low levels of pesticide residue cited in recent news reports is a tiny fraction of the amount that the government allows. Consumers are regularly bombarded with alarming headlines, but rarely have the time to weigh the information for themselves,” General Mills said.

Quaker said in an email that the EWG report uses a level for glyphosate “that is detached from those that have been established by responsible regulatory bodies in an attempt to grab headlines.”

“The Quaker products tested by EWG are safe,” the company added.

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Back in August, the Environmental Working Group (EWG) conducted testing and found 31 out of 45 tested breakfast foods and cereal products had higher levels of glyphosate than what some scientists consider safe for children.

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