"The nicotine in e-cigarettes and regular cigarettes is addictive. E-cigarettes are considered tobacco products because most of them contain nicotine, which comes from tobacco.
Besides nicotine, e-cigarettes can contain harmful and potentially harmful ingredients, including:
>ultrafine particles that can be inhaled deep into the lungs
>flavorants such as diacetyl, a chemical linked to serious lung disease
>volatile organic compounds
>heavy metals, such as nickel, tin, and lead"