Banned chemical is found in popular oat brands eaten by millions of people

A pesticide that American farmers cannot spray on food crops is still turning up in the breakfast bowls of millions. Tests show that chlormequat sneaks into best selling oat cereals despite the domestic ban on food uses.

In a peer reviewed survey of 96 adults, scientists detected the chemical in 77 urine samples, an 80 percent hit rate that points to routine exposure.

What is chlormequat?

Alexis M Temkin, PhD, a toxicologist at the Environmental Working Group (EWG), explains that the compound is a plant growth regulator that stiffens grain stalks so they do not lodge in bad weather.

Because shorter stems make harvesting easier, growers in Canada and Europe apply the chemical widely to oats, wheat, and barley.

The National Library of Medicine classifies chlormequat as approved only for ornamental plants inside U.S. greenhouses, not for any edible crop.

A changing regulatory landscape

The Environmental Protection Agency (EPA) opened the door in 2018 by allowing imported foods with allowable residues, then doubled the residue limit for oats in 2020, a move critics say signaled acceptance rather than caution.

Domestic use remains under review, yet the agency proposed granting farmers direct access in 2024, sparking a flood of public comments from pediatricians, growers, and consumer advocates.

Temkin warns that incremental rule changes can translate into large jumps in exposure because oats are baked into cereals, snack bars, and even baby food.

Signs of chlormequat on the rise

The new urine analysis shows median concentrations tripling between 2017 and 2023, suggesting that imported oats are already reshaping the U.S. chemical landscape.

Researchers also found the substance in 92 percent of non organic oat products purchased in Washington, DC grocery stores, while wheat products rarely registered positive.

Because chlormequat leaves the body in roughly twenty four hours, repeated detection indicates daily intake, not a one time spike.

Temkin calls the finding “alarm bells about how it could potentially cause harm without anyone even knowing they’ve consumed it,” a statement released through EWG.

Animal studies and fertility

Laboratory work over four decades links dietary chlormequat to reduced sperm quality, delayed puberty, and altered fetal growth at doses lower than current regulatory limits.

Pig experiments in Denmark first flagged reproductive trouble when sows fed treated grain failed to cycle normally.

More recent mouse studies showed testosterone drops of up to forty percent, reinforcing the suspicion that the chemical disrupts steroid synthesis.

Why oats are vulnerable

Oats grow in cooler, wetter climates where plants tend to fall over, so farmers lean on growth regulators more than maize or rice producers.

The slender hull of the oat kernel also absorbs residues easily, meaning what goes on in the field can stay through milling, baking, and shipping.

Unlike wheat, most oats eaten in the United States are imported from Canada, a country that allows routine chlormequat spraying, creating a direct pipeline from prairie fields to pantry shelves.

Industry response

Cheerios maker General Mills maintains that “All our products adhere to all regulatory requirements,” said company spokesperson Mollie Wulff.

Quaker echoed that stance, saying it follows “a comprehensive food safety management system” for its oats and bars.

Cereal processors note that detected levels fall below the EPA reference dose of 0.05 milligrams per kilogram of body weight per day, though toxicologists counter that the reference is based on decades old data.

Children on the front line

EWG’s calculations suggest that toddlers who eat a small bowl of conventional oatmeal could consume more chlormequat per pound of body weight than adults, eroding any margin of safety.

Pediatric dietitians point out that oat based finger foods are frequently marketed as “first solids,” giving the youngest consumers disproportionate exposure during critical developmental windows.

Choosing USDA Organic oats cuts residue dramatically, with only one of eight organic samples in the 2023 survey testing positive and at a fraction of conventional levels.

Steel cut oats sourced from domestic processors also showed lower contamination, hinting that where grain is grown can matter as much as how it is processed.

Chlormequat policy options

Health advocates want the EPA to tighten residue limits, add chlormequat to the Pesticide Data Program, and apply extra safety factors for children, mirroring rules already used for other endocrine disruptors.

State lawmakers in New York and California are considering bills that would require front of package disclosure when grains exceed advisory levels, a strategy meant to shift market demand toward lower residue sources.

Major retailers could accelerate change by setting private standards, a tactic that has successfully reduced antibiotics in meat and BPA in food contact plastics.

What parents can do now

Nutritionists recommend rinsing quick oats before cooking and diversifying breakfasts with eggs, yogurt, and fresh fruit, steps that dilute overall exposure without major lifestyle changes.

Parents who rely on oat based snacks can look for organic certification or brands that publish independent residue tests, a small but growing niche in the cereal aisle.

A call for better monitoring

Consumer groups are urging the federal government to add chlormequat to routine pesticide sampling programs and to set children specific safety factors that reflect the latest animal evidence.

Temkin and colleagues want larger epidemiological studies that track fertility outcomes in communities with high oat consumption, similar to historic work on other endocrine disruptors.

Until such data arrive, simple breakfast choices will continue to serve as an unintended experiment in chemical policy.

The study is published in the Journal of Exposure Science & Environmental Epidemiology.

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