Abstract
Tetrahydrocannabinol (THC), a psychoactive substance found in Cannabis sativa plants, including varieties such as hemp, is increasingly being used in consumer products. On October 24, 2024, local emergency medical services reported to Public Health Madison & Dane County (PHMDC) in Wisconsin that since October 22, they had transported seven persons to a local hospital for various symptoms, including dizziness, sleepiness, and anxiety. All seven persons reported having recently eaten food from the same local restaurant. Investigation by PHMDC determined that on October 22, the restaurant had run out of cooking oil and used oil from a cooperative (i.e., shared) kitchen located in the same building. One of the vendors who used the kitchen made edible products using hemp-derived Δ(9)-THC. On October 24, PHMDC posted a food and symptom history questionnaire on its website and shared the link via press release and social media. Among 107 responses that were considered valid, 85 persons met the following case definition of THC intoxication: 1) ate pizza, garlic bread, cheese bread, or a grinder (submarine sandwich) purchased from the restaurant during October 22-24 and 2) reported at least one symptom of THC intoxication that began within 5 hours after eating the restaurant's food, defined as dizziness, sleepiness, anxiety, short term memory impact or time distortion, increased heart rate, nausea, paranoia, panic attack, increased blood pressure, vomiting, or hallucinations. Clinicians and public health practitioners should be alert to the possibility of mass THC intoxication events via food. Health care providers, public health professionals, and emergency responders should consider THC intoxication in persons with sudden onset of symptoms such as dizziness, sleepiness, anxiety, altered reality perception, increased heart rate, nausea, or other symptoms of THC ingestion. Regulations regarding practices such as standard, clear labeling and locked storage for ingredients containing THC, might decrease the risk for unintentional THC exposure at licensed food businesses.