Electronic Nicotine Delivery Systems

male with ecigarettes

Electronic nicotine delivery systems (ENDS) such as e-cigarettes, e-hookahs, e-pipes and e-cigars are devices that deliver aerosolized nicotine, flavorings, and/or other chemicals into the lungs of users. Use of ENDS is sometimes referred to as “vaping.” A typical ENDS device contains three main components: a battery, a heating element, and a cartridge or tank that holds the e-liquid.1  Some of the newer devices look like USB sticks and have a disposable pod containing the e-liquid. The e-liquid is a solution that typically contains a mixture of  nicotine, propylene glycol and glycerin. Additionally, e-liquid may also contain flavoring chemicals.2-4 When an ENDS user takes a puff from a device, the e-liquid is heated by the heating element and forms an aerosol and gases that the user inhales into their lungs. A portion of the aerosol and gases taken into the ENDS user’s lung is exhaled, which may result in exposure to bystanders in proximity to the user.5-6 A portion of the aerosol taken into the ENDS user’s lung is exhaled, which may result in exposure to bystanders in proximity to the user.

Use of ENDS is rising among never-tobacco smokers and former or current tobacco smokers.6-9 In 2017, e-cigarettes were used by approximately 2.8% (6.9 million) of U.S. adults.10  While ENDS aerosol may differ in some ways from tobacco smoke, users of ENDS and those around persons using ENDS are still exposed to many different types of chemical compounds (some of which are known carcinogens), very small particles, and numerous hazardous metals.11-13 Chemicals emitted in ENDS aerosols can include carcinogens such as formaldehyde, polyaromatic hydrocarbons, and other chemicals, as well as various organic compounds that are irritating to the lung, and flavoring compounds.14,16-18 Among flavoring compounds emitted in some ENDS aerosol are 2,3-pentanedione and diacetyl, which NIOSH has linked to causing obliterative bronchiolitis, a devastating lung disease in workers.4 Other flavoring chemicals can generate free radicals, which cause oxidative stress and are thought to influence the development of many tobacco-related diseases, such as cardiovascular disease, chronic obstructive pulmonary disease (COPD), and cancer.19 In addition to concerns about chemicals emitted from ENDS, there is also a risk of burns following spontaneous combustion of the lithium battery in the device.16

The potential health risks to users or bystanders exposed to secondhand smoke from ENDS is still under investigation. NIOSH issued a Current Intelligence Bulletin 67: Promoting Health and Preventing Disease and Injury Through Workplace Tobacco Policiespdf icon, that recommends employers establish “smoke-free workplaces that protect those in workplaces from involuntary, secondhand exposures to tobacco smoke and airborne emissions from e-cigarettes and other electronic nicotine delivery systems.” This recommendation covers all varieties of ENDS including e-hookahs, e-pipes, e-cigars, e-cigarettes and advanced modular ENDS. Some e-cigarettes are used to deliver aerosolized illicit drugs such as cannabis, methamphetamines, and cocaine to the user. By adding the illicit drug to the e-liquid, it may alter the characteristic of the drug (such as smell), making it difficult to know if a person is using an illicit drug.20


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Page last reviewed: November 16, 2016