Pesticide chlormequat found in Cheerios, other oat-based foods: report

A pesticide not approved for use on U.S. crops has been found in an overwhelming majority of oat-based products including major cereal brands such as Quaker Oats and Cheerios, according to a new peer-reviewed study from the Environmental Working Group.

The report, published this month in the Journal of Exposure Science and Environmental Epidemiology, detected the presence of chlormequat chloride in four out of five, or 80%, of people tested. It also found the chemical in 92% of oat-based foods purchased in May 2023, including in popular breakfast brands.

A lesser-known chemical for plant-growth regulation, chlormequat is associated with the potential to cause reduced fertility and harm to developing fetuses in animals, according to the study. It could carry similar risks for humans.

The U.S. has not approved chlormequat for food crops, and the pesticide can only be used on ornamental plants. However, beginning in 2018, the U.S. began accepting imports of oats from countries where the chemical is allowed. It’s also considering expanding approval of the pesticide, with the Environmental Protection Agency proposing to register the pesticide for use on food crops for the first time.

“These regulatory changes might help explain why we’re seeing more frequent, higher detections of the chemical in Americans tested,” EWG said in a statement accompanying the release of the study.

Researchers analyzed urine samples from U.S. adults, from 2017 to 2023. Chlormequat was detected at frequencies of 69%, 74% and 90% for samples collected in 2017, 2018–2022 and 2023, respectively. The study also tested food.

Researchers noted that the study’s participants were likely exposed to chlormequat at much lower levels than doses that regulators from the U.S. and Europe have deemed acceptable. However, mice and pigs exposed to lower levels of the chemical during other studies exhibited reduced fertility.

“Research about chlormequat’s effects is ongoing, and no studies have determined how much of a risk this chemical might pose,” EWG said. “That’s where the government has a vital role to play in overseeing the future of chlormequat in the U.S.”