Mark L. RubinsteinKevin DelucchiNeal L. BenowitzDanielle E. Ramo

BACKGROUND: There is an urgent need to understand the safety of e-cigarettes with adolescents. We sought to identify the presence of chemical toxicants associated with e-cigarette use among adolescents.

METHODS: Adolescent e-cigarette users (≥1 use within the past 30 days, ≥10 lifetime e-cigarette use episodes) were divided into e-cigarette–only users (no cigarettes in the past 30 days, urine 4-[methylnitrosamino]-1-[3-pyridyl]-1-butanol [NNAL] level <1 pg/mL of creatinine; n = 67), dual users (use of cigarettes in the past 30 days in addition to e-cigarettes, NNAL level >30 pg/mL; n = 16), and never-using controls (N = 20). Saliva was collected within 24 hours of the last e-cigarette use for analysis of cotinine and urine for analysis of NNAL and levels of 8 volatile organic chemical compounds. Bivariate analyses compared e-cigarette–only users with dual users, and regression analyses compared e-cigarette–only users with dual users and controls on levels of toxicants.

RESULTS: The participants were 16.4 years old on average. Urine excretion of metabolites of benzene, ethylene oxide, acrylonitrile, acrolein, and acrylamide was significantly higher in dual users versus e-cigarette–only users (all P < .05). Excretion of metabolites of acrylonitrile, acrolein, propylene oxide, acrylamide, and crotonaldehyde were significantly higher in e-cigarette–only users compared with controls (all P < .05).

CONCLUSIONS: Although e-cigarette vapor may be less hazardous than tobacco smoke, our findings can be used to challenge the idea that e-cigarette vapor is safe, because many of the volatile organic compounds we identified are carcinogenic. Messaging to teenagers should include warnings about the potential risk from toxic exposure to carcinogenic compounds generated by these products.


  • Abbreviations:
    AAMA — 
    2-carbamoylethylmercapturic acid
    CNEMA — 
    2-cyanoethylmercapturic acid
    e-cigarette — 
    electronic cigarette
    HEMA — 
    2-hydroxyethylmercapturic acid
    HMPMA — 
    3-hydroxy-1-methyl-propylmercapturic acid
    NNAL — 
    PMA — 
    phenylmercapturic acid
    VOC — 
    volatile organic compound
    2-HPMA — 
    2-hydroxypropylmercapturic acid
    3-HPMA — 
    3-hydroxypropylmercapturic acid


What’s Known on This Subject:

The presence of harmful ingredients in electronic cigarette vapor has been established.

What This Study Adds:

We have demonstrated that at least 5 potentially harmful toxicants are found in the body of human adolescents who use electronic cigarettes.


Unfortunately, teens perceive themselves as being bullet-proof.  I still think that E-Cig’s are safer.  There are >700 toxins in tobacco including the flavorings and additives used.  Admittedly, plasticizers are present in the Vapes that are not found in cigarettes, but the Vapes seem to still be a bit safer (but by no means SAFE) and my experience is that E-Cig’s are a useful tool to get folks off of tobacco.  I tell my patients that I do NOT wan them to stop smoking–only to switch (NOT alternate!) what they smoke and wean down as they’re able to do so.  It works!

Dr. Raymond Oenbrink