Is Propylene Glycol Dangerous to Inhale? Safety and Use in E Cigarettes SMOKO E Cigarettes Propylene Glycol In Vapes Food Grade Propylene Glycol Toxicity and Appeal of Flavoured E Cigarettes and Flavour Ban Outcomes: A Narrative Review Vape Juice Ingredients: What's Really Inside? (2026) Cyclone Pods Researchers at the University of California, Riverside, found that heating propylene glycol, the main ingredient in most e cigarette liquids, can produce two toxic chemicals, methylglyoxal and acetaldehyde, which damage lung cells. Using E cigarettes and the ob gyn: Key safety information for prenatal counseling Contemporary OB GYN