Glyphosate, the active ingredient in the weed killer Roundup, is the focus of U.S. lawsuits from more than 11,200 plaintiffs claiming exposure to the chemical caused cancer or other illnesses.

Concerns are rising among consumers and families about the safety of glyphosate amid tests from environmental groups finding the chemical in cereals like Cheerios.

A new research study of 12 families detected the chemical in 11 of them, with most children having higher levels of glyphosate in their bodies than their parents.

Glyphosate, the active ingredient in the weed killer Roundup, is facing an unprecedented test in the courtroom, with more than 11,200 people alleging in pending lawsuits that exposure to the chemical led to cancer or other injuries. At the same time, the chemical is facing a trial of public opinion amid rising concerns about its safety.

Tests from environmental groups are raising alarm with consumers, such as a recent study finding 21 oat-based cereal and snack products, including Cheerios, contain traces of glyphosate. That caught the attention of many parents, given the popularity of Cheerios among kids. Now, a new, small study from another environmental group found higher levels of glyphosate in children than their parents.

The lawsuits and studies are prompting concerns among some parents and families about the chemical, which is used by farmers to control weed growth in their crops as well as by schools and municipalities in public spaces like school grounds and parks. So far, Bayer -- which bought Roundup's maker Monsanto last year -- has lost three high-profile court cases that claimed the chemical caused cancer.

"I'm totally concerned seeing the lawsuits around Roundup, knowing the association that might exist between glyphosate and cancer," said Judith Robinson of Marlboro, Vermont, who with her 14-year-old daughter participated in the recent study of levels of glyphosate in parents and their children.

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Robinson said she was "floored" by the results, which found her daughter's levels were about 100 times higher than her own, and approached her daughter's school district about providing more organic foods on the lunch menu. She said the discussions have revitalized efforts to create a healthy food program at the school.

"People want to know what changes they have to make" to limit exposure to glyphosate, she added.

Bayer's stock plunge

That's among the headwinds facing Bayer, whose stock has plunged by almost half since its acquisition of Monsanto closed on June 6, 2018. In its annual report, Bayer said it expects more lawsuits to emerge.

Glyphosate is safe, Bayer told CBS MoneyWatch in an email, citing the U.S. Environmental Protection Agency's assessment that there are "no risks of concern from ingesting food with glyphosate residues."

Yet conclusions from various scientific groups are contradictory, with the World Health Organization's cancer agency saying it's "possibly carcinogenic to humans." But a long-term study of agricultural workers didn't find a link between Roundup and cancer.

Known unknowns

The new study, released Wednesday by the environmental group Center on Environmental Health, tested 12 families for glyphosate levels and found that 11 tested positive. Among 10 families, the children had higher levels of the chemical than their parents, the CEH said.

Bayer criticized the size of the study, noting it "provides results from a small group of volunteers with no information to determine whether the results are reliable." It added, "Assuming that these results are accurate, the reported values do not raise any human health concerns and are thousands of times below strict exposure limits set by safety authorities."

To be sure, the study represents a small sample size, and it's difficult to extrapolate nationally from the study. But the findings are consistent with previous research, said Dr. Emanuela Taioli of Mount Sinai, who published a review of studies on glyphosate levels in adults and children in the journal Environmental Health earlier this year.

"Although the number of families is small, the study ultimately measures samples for 24 people, making it a larger sample size than it first appears to be," Taioli said of the Center on Environmental Health study. "Even a small study adds to a body of research that is currently very limited, and is therefore valuable."

She added that the tests finding levels of glyphosate in humans suggests more studies are needed. "It is hard to say what cut off level below which glyphosate exposure is considered 'safe,' as the literature is scarce, and there is not an established regulatory level," she said.

Playground use

That was echoed by Caroline Cox, senior scientist at the Center on Environmental Health who worked on the study of 12 families. "What level is a problem, we just don't know," she said. "I would rather that U.S. families not have to be the guinea pig to find that out."

Cox said she believes children may have higher levels of glyphosate than their parents because of their diets, such as eating more cereals and grains, as well as exposure via playgrounds and parks where Roundup is sprayed. She said she recommends eating organically grown foods to avoid exposure to glyphosate, and talking with schools and municipalities to limit spraying of glyphosate.

Already, some parents are raising those questions, with families in Cleveland and Michigan asking their schools to reconsider Roundup use on their grounds.

Bayer said sales of glyphosate "remain strong" although it doesn't break out sales numbers. Reuters has reported that Roundup sales were $4.8 billion in 2015, when Monsanto was its own company.

"We are also heartened by the fact that the sales of our glyphosate herbicides remain strong because our customers who know our products best continue to rely on them, and their own experiences confirm that they can be used safely and are effective tools for controlling weeds and supporting sustainable farming practices," Bayer said in a statement to CBS MoneyWatch.

Eating organic?

Still, it's hard to say whether there's cause for concern without more research, Taioli said. "Buying organic produce and being sure to wash produce before eating it is one way to help limit exposure if people are concerned, although glyphosate has also been found in the water by the EPA and in processed food like children's breakfast cereals," she noted.

Robinson, the mother who participated in the CEH study, she said she participated in the project study because she eats a gluten-free diet and her daughter consumes a lot of bread and wheat products and thought they'd be a useful comparison. Robinson said she was also concerned because her daughter has Down syndrome, which carries higher risks for some illnesses. Since getting the results, she's changed her daughter's diet, she added.

"Once you realize that someone who is very average like myself and my daughter has these levels, it could be anybody," she said. "We're not special. We resemble the rest of America and we have a home that's similar to the rest of America."