FILE - Harvesting grain at a farm in Ontario, Canada, on Sept. 30, 2022. (Photo by Creative Touch Imaging Ltd./NurPhoto via Getty Images)
Chlormequat, a little-known pesticide used in the production of oats and other imported products, was found in four out of five people tested in a recently-published study.
The chemical has been linked to reproductive and developmental problems in previous animal studies, raising questions about the potential harm for humans, the researchers said.
RELATED: Largest-ever COVID vaccine study links shot to small increase in heart, brain conditions
The peer-reviewed study, published on Thursday in the Journal of Exposure Science and Environmental Epidemiology, tested the urine of 96 U.S. adults for the presence of chlormequat, and found it in 77 of the participants.
The researchers also detected high levels of chlormequat in a majority of oat-based foods purchased last year, according to the study.
What is chlormequat?
This browser does not support the Video element.
What are PFAS, the concerning 'forever chemicals?'
PFAS are increasingly being found unnaturally in water sources, food, and animals.
Chlormequat is a type of chemical used primarily on grain crops like oats and wheat to alter the plant growth and keep the plants from bending over, which can make harvesting more difficult.
In the U.S., chlormequat can be used on ornamental plants, such as those used for decorating a space rather than for food or medicinal purposes, according to Environmental Protection Agency regulations.
But since 2018, the EPA has permitted chlormequat on imported oats and other foods, increasing the allowed amount in 2020, said the Environmental Working Group, a research and advocacy nonprofit that conducted the new study.
RELATED: E. coli outbreak linked to raw cheese: Here’s what you need to know
Chlormequat found in majority of oat-based foods tested
In 2022, EWG said it found "high detections" of chlormequat in several oat-based products. Last year, it tested 20 more oat-based foods for chlormequat: seven organic and 13 non-organic, as well as nine wheat-based products.
"Detectable levels" of chlormequat were found on 92% of the non-organic oat-based foods tested, the EWG said. Only two samples of wheat-based foods – both of them bread – had low levels, the group added.
Meanwhile, only one of the seven organic samples had low levels of chlormequat, the EWG said.
Specifically, the EWG said Quaker Oats and Cheerios were among the products tested that had detectable levels of the chemical.
General Mills, which makes Cheerios, shared in a statement to FOX Television Stations that all of its products "adhere to all regulatory requirements."
"Food safety is always our top priority at General Mills, and we take care to ensure our food is prepared and packaged in the safest way possible," Mollie Wulff, a spokesperson for General Mills, added in a statement.
PepsiCo, the parent company of Quaker Oats, did not immediately respond to a request for comment. However, the company told CBS MoneyWatch that it has a "comprehensive food safety management system in place" and adheres to "all regulatory guidelines to ensure the safest, highest quality products for our consumers."
Prevalence of chlormequat exposure on the rise?
EWG tested for the presence of chlormequat in urine collected from 96 people between 2017 and 2023.
Its testing found higher levels and "more frequent detections" of chlormequat in the 2023 samples, compared to those from 2017 through 2022, according to EWG – which added that the findings suggest consumer exposure to chlormequat "could be on the rise."
"EWG’s new study on chlormequat is the first of its kind in the U.S.," EWG Toxicologist Alexis Temkin, Ph.D, and lead author of the study, said in a statement. "The ubiquity of this little-studied pesticide in people raises alarm bells about how it could potentially cause harm without anyone even knowing they’ve consumed it."
Research about the effects of chlormequat remains ongoing, and no studies have determined how much of a risk this chemical might pose to humans, the EWG said.
The EPA is considering a plan to let chlormequat be used on barley, oat, triticale and wheat grown in the U.S., in an effort to "provide farmers with an additional tool to help increase crop yield." The EWG said it opposes this plan.
"Until the government fully protects consumers, you can reduce your exposure to chlormequat by choosing products made with organic oats, which are grown without synthetic pesticides such as chlormequat," the EWG said.
RELATED: Bubonic plague: What to know after Oregon cat gives owner rodent-borne disease
This story was reported from Cincinnati.