A commissioned investigation has found that all tested Girl Scout cookie samples contained glyphosate and toxic metals, with some exceeding EPA water safety limits. Researchers, led by Stephanie Seneff, PhD, a senior research scientist at the Massachusetts Institute of Technology, tested 25 cookie samples from 3 states for contamination.

Findings from the study—published on GMOScience.org—revealed that 100% of samples tested positive for glyphosate, an herbicide commonly used as a drying agent in crop production. Thin Mints showed the highest glyphosate levels, at 111.07 ppb, while Peanut Butter Patties contained 13.57 ppb. According to the report, these levels are "334 times higher than what Dr. Don Huber, Professor Emeritus of Purdue, states is harmful and must be avoided."

Heavy metal contamination was also widespread, with 88% of samples (n = 22/25) testing positive for all five toxic metals examined: aluminum, arsenic, cadmium, lead, and mercury. Notably, 76% of samples exceeded U.S. Environmental Protection Agency (EPA) water limits for cadmium (5 ppb), and 96% contained detectable lead levels.

"The health implications of toxic substances in [Girl Scout] cookies extend beyond the immediate impact on our girls and affect the public at large," the researchers wrote. "Identifying and eliminating the sources of these toxic metals is imperative to safeguarding public health."

The study examined cookies from California, Iowa, and Louisiana, analyzing products from both major Girl Scout cookie manufacturers: ABC Bakers and Little Brownie Bakers. Peanut Butter Patties showed the highest contamination levels for heavy metals, with lead concentrations reaching 42.5 ppb and aluminum levels at 27.5 ppm (27,500 ppb).

The researchers noted that the Girl Scouts USA organization—which sells approximately 200 million boxes of cookies annually and collects about $800 million in revenue from the sales—was contacted before the study's publication, but did not respond to meeting requests.

The study authors propose transitioning to organic and regenerative farming practices as a solution, estimating that the organization's annual wheat flour usage represents approximately $16 million in purchasing power that could influence agricultural practices.

The research was conducted in collaboration between GMOScience, Moms Across America, and other consumer groups, with funding acknowledgment to The Westreich Foundation.

Reference: Seneff S, Perro M, Honeycutt Z. Danger in the Dough: Unveiling the Toxic Contaminants in Girl Scout Cookies. GMOScience. December 2024.