The American Vaping Association said most of these mishaps are caused by improper use when someone has loose batteries in their pocket that touch coins and short circuit or improperly rebuilds the heating coils and causes the battery to overheat
Effects of Cigarette Smoke Exposure on Innate Immunity The innate defense mechanisms of the airways and lungs encompass structural components, cough reflex, mucociliary clearance, epithelial barrier, humoral factors (surfactant proteins, complement proteins, antimicrobial peptides), and cells that elicit immune responses (epithelial cells, macrophages, monocytes, dendritic cells, neutrophils, natural killer cells, and mast cells)
The liquid is a mixture of a handful of ingredients
But there are numerous competitors, and many users modify the devices and use aftermarket replacement batteries