Propylene glycol, a component of electronic cigarette liquid, damages epithelial cells in human small airways Respiratory Research Springer Nature Link Nicotine, propylene glycol, sweet flavorings, and various toxic chemicals like carcinogens and heavy metals are found in vape juice, posing health risks, especially to youth. Menthol in electronic cigarettes causes biophysical inhibition of pulmonary surfactant American Journal of Physiology Lung Cellular and Molecular Physiology American Physiological Society All E Cigarettes Emit Harmful Chemicals, but Some Emit More Than Others Berkeley Lab Berkeley Lab News Center Propylene hi res stock photography and images Alamy PG vs. VG A Vapers Guide SMOKO E Cigarettes SMOKO E Cigarettes