Girl Scout cookies may contain heavy metals. Why is our food like this?

Baby food, spices, chocolate. And now, Girl Scout cookies. In recent years, tests have found heavy metals like lead in some of the most common food products in American households.

A proposed class-action lawsuit filed earlier this week blames the Girl Scouts for the presence of heavy metals and the herbicide glyphosate in its cookies, citing a study that wasn't peer reviewed of a small sample size of cookies purchased in three states.

In those cookies, according to the analysis commissioned by Moms Across America and GMO Science, four out of five heavy metals tested for were present in all the cookie samples, and most of the 25 cookie samples tested had all five: aluminum, arsenic, cadmium, lead and mercury.

The Girl Scouts, meanwhile, defended their cookies as safe to eat, and said its products are manufactured according to current safety standards. Their bakers don't add any contaminants, and any of these substances found in the cookies come from environmental exposure, the Girl Scouts said.

The Girl Scout cookie debacle is the latest instance of a food product raising alarm over the presence of contaminants. Aside from heavy metals and herbicides, Americans have also faced product recalls over listeria, salmonella and E. coli. Bird flu virus was found in raw milk. The Food and Drug Administration earlier this year banned Red Dye No. 3 from food and drinks over concerns about modern research suggesting it may be linked to cancer and behavioral issues in children.

Americans are on edge over the safety of their food, said Jerold Mande, an adjunct professor of nutrition at Harvard's School of Public Health and a former senior policy official at the FDA and the U.S. Department of Agriculture's food safety programs in the Obama administration.

But it's not surprising that Girl Scout cookies contain some amount of contaminants, and given a sensitive enough test, most processed foods would probably come back positive for at least one toxin or another, Mande said.

The question, according to Mande, should be: how much is too much? (And who gets to decide that?)

Mande said even foods that fall below the required threshold for contaminants might be behind health issues plaguing Americans, because there just isn't enough research being done by government scientists to answer those questions.

"Consumers are rightly concerned, and I'm concerned," Mande said. "But there's nothing you can do as an individual to really protect yourself, unless you're going to grow all the food yourself, and even then there can be contaminants."

How do heavy metals get into food?

At the advent of many food safety regulations and the FDA itself, tests for contaminants weren't as sensitive as they are today, Mande said. And when lawmakers passed laws like the 1950s-era Food Additives Amendment that banned any amount of cancer-causing substances from food, testing for such substances may have only been in the parts-per-million range. Now, scientists can test in parts per billion or trillion, Mande said, revealing much tinier amounts in many more foods than previously known.

When testing at such a sensitive level, he said, contaminants can probably be found in many household food products.

There are several pathways that may lead heavy metals to the food we eat. Some are naturally occurring in the environment. Others trace back to the widespread use of pesticides in crops that contained heavy metals, Mande said. While they're no longer used on food crops, they've long since contaminated soil, water and even the air. Sometimes heavy metals get into food during their processing.

The levels found in foods depend on how much a plant or animal "takes up" from the environment, according to the FDA.

Cadmium, for example, is "a naturally occurring metal," said Ana M. Rule, assistant professor and director of the Exposure Assessment Laboratories at Johns Hopkins Bloomberg School of Public Health.

“But just because they’re naturally occurring, doesn’t mean they’re safe," Rule told USA TODAY last year when high levels of cadmium were found in chocolate.

Should Americans be worried about their food?

Heavy metals are linked to a variety of acute and long-term illnesses and developmental issues, particularly in young children.

The FDA has set some recommended lead levels for babies and young children – and is in the midst of developing similar levels for arsenic, cadmium and mercury – but doesn't have suggested levels for the general population. Instead, the agency says its goal is to reduce the levels of contaminants such as arsenic, lead, cadmium and mercury in food.

"It's hard to get a low lead" level in certain foods, Mark Corkins, division chief of pediatric gastroenterology, hepatology and nutrition at the University of Tennessee Health Science Center, told USA TODAY in 2023 after Consumer Reports found heavy metals in baby foods.

"To be honest, there's nothing that's going to be completely free of any contamination," Corkins said.

As to whether you can still eat the Girl Scout cookies on your shelf, Mande said it's a personal decision based on how much risk you want to take. But consider this: Heavy metals and other toxins can probably be found in all manner of foods in our pantries if we were to use sensitive enough tests.

"There’s no question, almost every individual is taking greater risks in your day than what would come from that Girl Scout cookie that’s meeting government standards but that still has detectable levels," Mande said.

Still, Mande said the fact that Girl Scouts promises its cookies adhere to regulatory standards shouldn't necessarily put consumers at ease, either.

The claim the cookies are safe "feels like they’re dodging the point," consumer protection and environmental attorney Vineet Dubey told USA TODAY. "It’s very hard for the Girl Scouts to claim that with any certainty."

Mande said there's still so much unknown about the chronic health impacts that chemicals in our food may cause, not just heavy metals. And Americans are experiencing much more chronic illness than other wealthy nations, Mande said.

Most of the food sold in the U.S. doesn't go through preapproval by the agency before they are put on the market, Mande said. When problems arise, they are usually caught after the fact. That means it's up to the companies themselves to self-determine that their foods are safe to eat, even when profit is their priority, he said.

"The government's not doing its job ensuring the safety of our food, and the industry's not doing its job ensuring the safety of our food," Mande said.