CU Boulder researcher warns of untested toxins in cannabis, calls for expanded safety measures

OG article by Courtney Yuen

February 20, 2026

A University of Colorado Boulder researcher, microbiologist Tess Eidem, Ph.D., warns that legal cannabis products may contain untested toxins, particularly certain Fusarium mycotoxins not screened for in state regulations due to lacking federal oversight. While cannabis undergoes testing for heavy metals, pesticides, microbes, and some mycotoxins, dangerous Fusarium varieties—like those causing vomitoxin—are often excluded, despite appearing in about 14% of samples per a University of Arizona study (versus <1% for required ones). Eidem links these to potential risks, including vomiting episodes possibly tied to cannabis hyperemesis syndrome, though causation remains unclear. In Colorado, failing products can be remediated via irradiation or ozonation and resold without labeling, but mycotoxins may persist. She advocates for expanded testing akin to food safety standards for crops like corn and wheat, criticizing the focus on remediation over prevention. The Colorado Marijuana Enforcement Division acknowledges concerns but notes limited data on inhalation risks and ongoing exploration of broader requirements. Eidem urges academic funding to study mycotoxin effects in various cannabis forms for better consumer protection.