Baby food in particular had the highest perchlorate levels.

Some experts are raising alarm after a component from rocket fuel was found in food. Perchlorate, which is also found in rockets, airbags, explosives and some types of plastic, was discovered in a range of foods in a new study by Consumer Reports.

For the study, researchers analyzed 196 samples from 63 supermarket products and 10 fast-food items for the presence of perchlorate. Some foods contained the chemical more frequently than others, with perchlorate most likely to appear in products classified as “baby/child food.”

But what is perchlorate and how concerned should you be about these results? Here’s the thing.

What is perchlorate?

Perchlorate is a chemical compound with a wide range of uses – and according to Dr. John D. Coates, director of the Energy & Biosciences Institute at the University of California, Berkeley, it is actually a component of rocket fuel. “Because it can be stored as a dry powder at atmospheric pressure, it is preferable as the primary oxidizer for burning the rocket fuel,” he says. “In this use, it replaces oxygen.”

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Perchlorate “can also be a breakdown product of bleach,” says Dr. Jamie Alan, associate professor of pharmacology and toxicology at Michigan State University. Perchlorate is “very water soluble and quite mobile in soils and sediments,” says Coates. Because of this, it spreads easily in the environment, he explains.

Some fertilizers contain naturally occurring perchlorate, says Andrea Kirk, PhD, a toxicologist and professor of environmental and occupational health at George Washington University’s Milken Institute School of Public Health. “These fertilizers were widely used in agriculture and may be one reason why perchlorate is found in places where there were never rockets,” she says.

In which foods has perchlorate been detected?

About 67% of samples tested by Consumer Reports had measurable levels of perchlorate, ranging from 2 to 79 parts per billion. Researchers found that products classified as baby/infant food, fast food, and fresh fruits and vegetables had the highest levels.

Food in plastic containers also had high perchlorate levels, followed by food in plastic film and cardboard.

Note: The Environmental Protection Agency (EPA) has set a safe exposure level for perchlorate at 0.7 micrograms per kilogram of body weight per day. However, according to Consumer Reports, many food safety experts believe this level could be significantly lower.

Perchlorate can also seep into the water supply, although according to Consumer Reports, people most commonly come into contact with it through food.

What are the symptoms of perchlorate exposure?

Perchlorate can affect thyroid function, Coates says. “Taking it can interfere with the production of thyroid hormones, which are regulated by iodine, leading to hypothyroidism,” he says. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), hypothyroidism is a condition in which the thyroid gland works more slowly, leading to symptoms such as fatigue, weight gain, slow heart rate and depression. However, Coates points out that perchlorate is used to treat people with hyperthyroidism (an overactive thyroid).

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“Children, especially infants and developing fetuses, are more vulnerable,” Kirk says. “That’s because thyroid hormones play an important role in brain development. In adults exposed to too much perchlorate, the effects may be reversible. But in babies, the damage can be permanent.”

Adults exposed to higher levels of perchlorate may have lower energy, coarse hair and dry skin, Kirk says. “A toddler may have a lower IQ than would otherwise be the case,” she says.

How to protect yourself

Many of the foods that contained perchlorate were processed foods and so-called “baby foods,” so limiting consumption of these foods may be helpful, Alan says.

When it comes to perchlorate in your water, Kirk recommends checking your city’s water quality report — which should be available online — and seeing if it contains information about perchlorate. “If the levels are high, you may want to consider filtering your water,” she says. Just remember to check if the filter you’re considering can remove perchlorate.

However, Kirk says that “it’s very difficult to know how much perchlorate might be in a food.” Her advice: “The best thing you can do to limit exposure from food is to eat a varied diet.”

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