EWG investigation: Dangerous agricultural chemical chlormequat found in popular oat-based products


  • EWG commissioned lab tests of 14 popular oat-based cereals, granola and other everyday products and found concerning amounts of the chemical chlormequat.
  • Chlormequat exposure in animal studies has caused a host of reproductive and other health problems, suggesting the potential for harm to human health.
  • Unless and until federal regulators act to get chlormequat out of our food, buying organic can help reduce your potential exposure to the chemical.

A new EWG investigation finds for the first time troubling concentrations of the toxic agricultural chemical chlormequat in oat-based products sold in the U.S., including everyday brands marketed to adults and children. The chemical may be harmful to human health.

Chlormequat was discovered in all but one of 13 non-organic oat-based cereals, granola and other products in EWG-commissioned tests conducted by an independent laboratory. Eleven products contained chlormequat levels higher than the amount we think is safe for children’s health, and one sample contained exactly that amount. 

This level – EWG’s health benchmark – is 30 parts per billion, or ppb,  equivalent to a blade of grass on a football field. It’s the most chlormequat we think someone can eat every day without facing potential health risks. The benchmark is based on a typical serving size. 

This EWG standard derives from studies in animals that showed chlormequat exposure during pregnancy altered growth and development in early life. We translate that health-protective level to a safe level in food using typical serving sizes of oat-based foods and average weights for children. (See Appendix 2.) 

Health benchmarks are based on the latest science, solely with the goal of protecting public health. They’re needed because of the large discrepancy between what is legally allowed in food and what is actually safe to consume.

Chlormequat is a type of chemical that alters plant growth in a variety of ways. It’s applied to oat and grain crops while they’re growing to stop them from bending over, since that can make harvesting difficult. 

Studies of animals exposed to the chemical show it can disrupt fetal growth and harm the reproductive system. These harms raise concerns about how chlormequat might pose dangers for human health, especially for children, because exposures during early life can lead to health harms later on.

Chlormequat is approved for agricultural commercial use on ornamental plants only – not  on oats or any other food products grown in the U.S. But imported oats can have chlormequat residue in them, which is how they end up in the food we eat. 

The Environmental Protection Agency recently permitted traces of chlormequat in U.S. food, including oats, wheat and barley. This change took place during the Trump administration, first in 2018, when it said food could be sold in the U.S., even if it had traces of chlormequat. Then, in 2020, the Trump EPA increased permitted levels of the chemical for oats. 

Allowing chlormequat to contaminate U.S. food was just one in a string of misguided Trump EPA decisions that promoted agricultural interests in the use of harmful chemicals and ignored the science on the risks of those substances. The Trump EPA failed to protect human health with chlorpyrifos and glyphosate – and now chlormequat.

Table 1. Chlormequat levels in conventional oat-based products

Chlormequat chart

Detailed results of oat-based products tests

To test for chlormequat, EWG bought 13 non-organic, or conventional, oatmeal, granola, cereals and other oat-based products, and one organic granola product, in spring and summer 2022. All but one had detectable levels of chlormequat. Quaker’s Old Fashioned Oats had the highest concentration, 291 ppb. The next highest samples, all above 100 ppb, included two more Quaker products, Honey Nut Oatmeal Squares and Maple and Brown Sugar Instant Oatmeal, as well as Great Value Oats & Honey Granola and Cheerios.

The only conventional product with no detectable level of chlormequat was Kellogg’s Special K Fruit and Yogurt. No chlormequat was detected in the single organic granola sample tested.

The oat-based product tests were conducted byAnresco, an independent, accredited lab in California.

Chlormequat exposure has been linked to health problems in mammals:
  • Disrupting fetal growth
  • Changing how heads and bones develop
  • Altering metabolism
  • Delaying development during puberty
  • Changing sperm’s ability to move efficiently
  • Decreasing testosterone production
  • Harming the nervous system

A chemical toxic to mammals

EPA approval of especially high levels of chlormequat in imported oats raises alarm because of the studies showing the chemical’s connection to developmental and reproductive toxicity in animals and risks for humans.

Studies published in the past several years showed that exposure to chlormequat in laboratory animals disrupts fetal growth, changing development of the head and bones and altering key metabolic processes. Other studies of laboratory animals found that chlormequat exposure during pregnancy could delay development during puberty and cause changes in sperm motility later in life. Another study found chlormequat could decrease the amount of testosterone produced

In the late 1980s, a Danish investigation into the effects of chlormequat in swine fed chlormequat-treated wheat found the chemical may harm pig reproduction at doses 20 times lower than what’s currently considered safe for human consumption. The researchers recommended swine be fed less chlormequat-treated grain. 

Similar findings were observed in studies in mice in the late 1990s and in recent investigations in rats, raising concerns over chlormequat’s toxicity for reproduction in mammals, especially at doses lower than what regulatory authorities consider safe.

And in EPA documents reviewing chlormequat’s toxicity, studies provided by chlormequat manufacturers showed it may harm the nervous system in adult rats, mice and dogs. 

These types of toxicity data in animal studies should raise red flags at regulatory agencies about concerns for the potential harmful impacts on human health – and should have led the EPA to ask the manufacturer for assessments of chlormequat’s effects on the developing nervous system. But it didn’t, and concerns persist about the impact of chlormequat on the developing brain. 

The fact we’re finding increasing amounts of chlormequat in U.S. food is further cause for concern, given its acute toxicity and severe poisoning and death reportedly caused by chlormequat ingestion – eerily similar to the deadly weedkiller paraquat.

Get Chlormequat Out of Our Food!

Add your name to EWG's petition calling on the EPA to get chlormequat out of our food:

How we got here: Companies seek more uses and higher amounts of chlormequat

Over the past few years, Taminco, a major U.S. manufacturer of chlormequat, has petitioned the EPA to increase the amount of the chemical legally allowed in food products and change how chlormequat is used.

Chlormequat was first registered for use in the U.S. in 1962 but only on ornamental plants. For over 50 years, imported food couldn’t legally contain chlormequat residue, and growers are not allowed to use the chemical in food crops grown in the U.S. 

But companies are trying to change that. 

In 2017, Taminco, a subsidiary of the giant Eastman Chemical Company, petitioned the Trump EPA to permit chlormequat in oats imported into the U.S. The company requested that a “tolerance” of 15 parts per million, or ppm, be allowed. It also sought tolerances for other grains and for meat products from animals that feed on these grains. In response, in 2018, the EPA established tolerances for oats and the other items.

Then, in 2019, Taminco petitioned the EPA to further raise the tolerance. In response, the agency increased the chlormequat tolerance on imported oats to 40 ppm, effective May 2020. The agricultural trade publication Top Crop Manager celebrated the decision, stating the higher tolerance “removes a significant hurdle for Canadian grain growers” that use chlormequat on oats.

Taminco has also submitted an application to the EPA to allow chlormequat to be used on oats and other grains grown in the U.S. If approved, this would likely dramatically increase the use of the chemical in a wide range of products, potentially leading to greater risk of exposure in humans and possible harm to the environment. The EPA is still reviewing Taminco’s application.

More stringent regulations needed

The Department of Agriculture and the Food and Drug Administration have the two biggest U.S. pesticide monitoring programs. But neither tracks chlormequat residues in oats and other food. Consumers and researchers are in the dark about the use of the chemical on products millions of Americans eat every day.

So how concerned should we be about the potential risk to our health stemming from chlormequat in oat-based foods in the U.S. marketplace, now that it’s been discovered? 

Chlormequat has been used on oats in Europe for decades, and it’s detected in nearly all people sampled in both the U.K. and Sweden. We haven’t yet studied how much this type of widespread exposure affects human health, but we have the evidence of animal tests to show us just how harmful it can be.

For years, EWG has pushed for the agricultural industry worldwide to use fewer pesticides and agricultural chemicals and limit them in the food supply – especially for those chemicals, like chlormequat, that make their way into our food.

Until that happens, we strongly encourage consumers to minimize their exposure to chlormequat by buying organic oats and oat-based products. This will better protect you and your family – and send a message to food and chemical companies about the need to get this chemical out of our food.

EWG also urges consumers to sign our petition to the EPA calling for the agency to get chlormequat out of our food.

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Appendix 1. Methodology

For chlormequat analysis, the limit of detection is 10 ppb, and the limit of quantification is 100 ppb. This means we can be certain of chlormequat detections between 10 ppb and 100 ppb. But we can only estimate the concentration. 

All products tested were purchased either at grocery stores in the Washington, D.C., metropolitan area or from a major online retailer. Samples were analyzed by Anresco, an independent, accredited laboratory in California, in tests commissioned by EWG.

Appendix 2. EWG health-based limit for chlormequat

EWG develops benchmarks for pesticides to protect children’s health against harms that can be caused by exposure to substances like chlormequat and glyphosate. Our health benchmark for glyphosate is 160 ppb, and for chlormequat it’s 30 ppb.

EWG’s chlormequat benchmark is based on our recommended maximum value for long-term dietary exposures of no more than 0.05 micrograms per kilogram, or µg/kg, body weight per day – 1,000 times smaller and more protective than the EPA’s chronic reference dose of 0.05 mg/kg body weight per day or 50 µg/kg body weight per day. 

Our recommendation for the chronic, or daily, daily exposure limit for chlormequat is 0.05 µg/kg body weight per day, calculated as follows:

  • Departure point of 5 mg/kg body weight per day, based on the 2020 study by Xiagedeer
  • Application of 10-fold safety factor due to the lack of No Observed Adverse Effect Level
  • Application of 10-fold safety factor due to database uncertainty
  • Application of 10-fold safety factor due to interspecies differences between animals and humans
  • Application of 10-fold safety factor due to sensitivity variation within the human population (intra-species variation)
  • Application of a 10-fold safety for children’s health protection.

Based on these calculations, EWG’s health-based limit for daily exposure to chlormequat is 0.05 µg/kg body weight per day.

Translating this concentration to a 60 gram serving of food – a single serving of granola or large bowl of cereal – and the weight of a 6- to 11-year old child (about 30 kilograms) points to a benchmark concentration of no more than 25 nanograms chlormequat per gram of food product, equivalent to 25 ppb. 

Similarly, if a child aged 1 to 2 years old weighing about 10 kilograms consumed 15 grams of food, the safe level of chlormequat would be 33 nanograms chlormequat per gram of food, or 33 ppb. So EWG’s health benchmark is 30 ppb for chlormequat in food. This value would also be protective during pregnancy. 


Xiagedeer B, Hou X, Zhang Q, Hu H, Kang C, Xiao Q, Hao W. Maternal chlormequat chloride exposure disrupts embryonic growth and produces postnatal adverse effects. Toxicology. 2020; 442: 152534

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