Consider the Consequences of Vaping: e Cigarettes Safety Not Yet Proven CANSA The Cancer Association of South Africa CANSA The Cancer Association of South Africa Propylene glycol, a component of electronic cigarette liquid, damages epithelial cells in human small airways Respiratory Research Springer Nature Link Propylene glycol in e cigarettes might keep us healthy, says researchers Liquid E Cigarettes Liquid nicotine used in e cigarettes still a danger to children despite recent E cigarettes can emit formaldehyde at high levels under conditions that have been reported to be non averse to users Scientific Reports