a lot of people dont want to hear me when i say this but the Navy published a study on vaping, that all of the big mods that people are doing and the customization is leading to using the wrong material for the coils and overheating (burning) of the cotton, your actually inhaling small amounts of burnt cotton and flakes of metal. do what you will but that is what was passed down to us VIA naval message right before i left the Navy. i dont know much else as its not my thing, but i do know that and it makes sense to me. as far as second hand there isn't any negative affects because its just vapor but its the first hand that i would say is just as bad as cigarettes. just my opinion, and by all means i dont plan on stopping cigars so i dont tell anyone to stop anything else. "if it feels good do it"