Pesticide chlormequat found in oat cereals, U.S. population samples — but scientists debate risks
A small study by a nonprofit advocacy organization for the first time found the pesticide chlormequat in the U.S. population and in food supplies, primarily grain, its authors said, though experts disagreed on the significance of the discovery.
Chlormequat is not currently permitted for use on American-grown food crops, though the United States Environmental Protection Agency is weighing a rule change that would permit its use.
The peer-reviewed study by researchers with the Environmental Working Group, published Thursday in the Journal of Exposure Science and Environmental Epidemiology, found the pesticide in an array of oat-based supermarket products including Cheerios and Quaker Oats.
It also found the pesticide in urine samples from 77 of 96 study participants, with higher concentrations found in samples taken in 2023 than in samples taken in 2017 and from 2018 to 2022.
WHAT TO KNOW
A study by a nonprofit advocacy organization found chlormequat, a potentially toxic chemical, in the U.S. population and in food supplies, including supermarket oat-based products including cereals, for the first time.
The study’s authors say that some previous animal testing found adverse reproductive and fertility impacts associated with the pesticide. They say more testing needs to be done.
Even at the highest concentrations detected in the EWG study, though, one scientist noted “someone would need to eat a kilogram per day” of oatmeal or an oat-based product to reach the concentration the EPA determined as potentially harmful.
Some animal studies have shown adverse reproductive and fertility impacts at doses lower than the concentration determined by the United States Environmental Protection Agency as potentially harmful, according to EWG researchers.
But the EPA, in an April 2023 memorandum supporting use of chlormequat outside on food crops, said the pesticide, when properly used, “has very low risk to human health.”
Even at the highest concentrations detected in the EWG study, “someone would need to eat a kilogram per day” of oatmeal or an oat-based product to reach the concentration the EPA determined as potentially harmful, said Jaymie R. Meliker, a Stony Brook University professor of public health not involved in the study.
As the EWG paper notes, “individual sample donors were exposed to chlormequat at levels several orders of magnitude below” the EPA threshold.
Olga Naidenko, EWG’s vice president for science investigations, said that level — .05 milligrams per kilogram of body weight per day — was set too high and without proper attention to higher risk groups like children. “We feel the EPA has allowed way too much chlormequat to be in the American food supply based on insufficient science,” she said. The EWG paper calls for monitoring of the pesticide in foods and people along with epidemiological and further animal studies.
A spokeswoman for Cheerios maker General Mills, Mollie Wulff, did not comment directly on the study but said in an emailed statement that “all our products adhere to all regulatory requirements. Food safety is always our top priority.”
Eastman Chemical, the company that first requested permission from the EPA for domestic food use for the pesticide, did not respond to requests for comment.
In a statement Monday, Quaker Foods said: "At Quaker, we stand by the safety and quality of our products. We have a comprehensive food safety management system in place. We adhere to all regulatory guidelines to ensure the safest, highest quality products for our consumers."
An EPA spokesman said he could not immediately comment.
Chlormequat is a chemical used to improve crop yields. By limiting plant size, it keeps grain stems from growing so tall they bend or break. It is found in some foods that are imported, primarily grains, and is permitted for use on domestically grown ornamental plants.
Chlormequat was not allowed on oats sold in the U.S. before the EPA granted approval in 2018, according to EWG, which said that could explain the increased levels detected.
Legalizing its use for domestic food crops could increase exposure for American consumers, with “a lot more products with higher concentrations,” said Dr. Pam Factor-Litvak, professor of epidemiology at Columbia University Medical Center, who was also not involved in the study. Given the ubiquity of oat and wheat products, “you probably eat them several times a day,” she said.
She called the study’s findings — particularly the increase of concentration over time in the urine samples — concerning. She did not recommend people stop eating Cheerios but said consumers should be “prudent” when it comes to wheat and oat products. “We certainly need studies in people that really suggest whether or not these compounds are harmful in people,” she said.
Meliker, of Stony Brook, said the EWG study appeared to be scientifically rigorous but questioned its purpose.
“We can detect anything that we’ve created, whether it’s in our blood or in our urine, and no doubt that’s an uncomfortable feeling.” But, he said, “you have to try to assess risk — it’s not just about understanding exposure.”
