DEPARTMENT OF HEALTH & HUMAN SERVICES

Public Health Service
Centers for Disease Control
and Prevention (CDC)
Atlanta GA 30341-3724

Office on Smoking and Health
U.S. Centers for Disease Control and Prevention
4770 Buford Highway
MS F-79
Atlanta, Georgia 30341-3717
Representative Debra J. Heffernan
Delaware General Assembly
411 Legislative Avenue
Dover, Delaware 19901
Dear Ms. Heffernan,
Per your request, I am submitting this statement of scientific evidence regarding electronic nicotine delivery
systems (ENDS; including e-cigarettes), including the health effects of ENDS aerosol. For the record, I am not
submitting this statement for or against any specific legislative proposal.
Please note that I will use the term ENDS throughout this letter, except where I am referring to study results that
looked at surveillance survey results for a particular product, such as e-cigarettes.
Current Status of ENDS Market and Product Regulation
E-cigarettes are part of a class of products also referred to as electronic nicotine delivery systems (ENDS), which
are battery-powered devices that provide doses of nicotine and other additives to the user in an aerosol.1 There are
currently multiple types of ENDS on the U.S. market, including e-cigarettes, e-hookahs, hookah pens, vape pens,
e-cigars, and others. Some of these products are disposable varieties, while others can be refilled or recharged for
repeated use.
ENDS that do not make therapeutic claims, including e-cigarettes, are currently not regulated by the U.S. Food
and Drug Administration (FDA) under the Family Smoking Prevention and Tobacco Control Act (FSPTCA),
although FDA issued a proposal in April 2014 to regulate them under its tobacco product authorities.2 If finalized
as written, the rule would establish, among other provisions: restrictions to prevent sales to minors, to prohibit
free samples, and to prohibit vending machine sales, unless in a facility that never admits minors.2 Additional
provisions, such as establishing a product standard prohibiting flavors could require additional rule-making.2
Furthermore, FDA regulation does not address certain key policy interventions related to ENDS, such as use in
public places.2 Section 916 of the Federal Food, Drug, and Cosmetic Act preserves the authority of States and
localities to enact, adopt, promulgate, and enforce laws, rules, regulations or other measures with respect to
tobacco products that are in addition to, or more stringent than requirements established under Chapter IX of the
Food, Drugs, and Cosmetics Act, including laws, rules, regulations, or other measures relating to or prohibiting
the sale, distribution, possession, exposure to, access to, advertising and promotion of, or use of tobacco products
by individuals of any age, information reporting to the State, or measures relating to fire safety standards for
tobacco products.3 Section 916, however, prescribes that no State or political subdivision of a State may establish
or continue in effect with respect to a tobacco product any requirement which is different from, or in addition to,
any requirement under the provisions of Chapter IX of the Federal Food, Drug, and Cosmetic Act relating to

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 tobacco product standards, premarket review, adulteration, misbranding, labeling, registration, good
manufacturing standards, or modified risk tobacco products.3
Additional national and—to the extent not preempted by federal law—state policies addressing retailer licensing,
Internet sales, taxation, and marketing could further prevent youth use of ENDS and other tobacco products.4
The current landscape of ENDS—including product design and availability, sales, marketing, use, and related
legislation—is one of rapid change and high variability. Significant questions remain regarding ENDS’  toxicity
and impact on patterns of conventional tobacco use. This testimony summarizes the available scientific literature
regarding ENDS, including surveillance data on experimentation and recent use; the health effects of ENDS,
including toxicant exposure to users and non-users and impacts on patterns of conventional tobacco use;
effectiveness of ENDS for quitting conventional smoking; ENDS marketing; smokefree policies and ENDS; and
evidence-based strategies to prevent and reduce tobacco use.
Current Patterns of ENDS Use
To date, surveillance questions on the use of ENDS have focused primarily on e-cigarettes. National surveys
show rapid increases in adult and youth use of e-cigarettes. Results from the HealthStyles survey suggest that U.S.
adult e-cigarette ever use nearly doubled from 2010 (3.3%) to 2013 (8.5%).5 Data from the National Youth
Tobacco Survey show ever use increased in U.S. middle and high school students from 2011 to 2013 (3.3% to
14.9%) and current e-cigarette use (use at least 1 day in the past 30 days) increased from 1.1% to 5.6%.1, 6 More
recent survey data from Monitoring the Future suggests an even more dramatic rate of current e-cigarette use
among high school students in 2014: 17% among twelfth graders—higher than the use of tobacco cigarettes.7
From 2011 to 2013, U.S. middle and high school students who had never smoked cigarettes but who had ever
used an e-cigarette increased over three-fold, from approximately 79,000 to over 263,000.8 Furthermore, intention
to smoke conventional cigarettes was 43.9% among U.S. middle and high school students who had ever used ecigarettes, whereas only 21.5% of students who had never used e-cigarettes reported intending to smoke
conventional cigarettes.8
These surveillance data also suggest that the majority of adults and youth who use e-cigarettes also use
conventional cigarettes.1,9,10
Health Effects of ENDS
A discussion of the health effects of ENDS should consider the consequences of toxicant exposure for ENDS to
both users and non-users, as well as potential impacts on patterns of use of other tobacco products.
I.

Toxicant Exposure to Users

Since ENDS that do not make therapeutic claims are not yet regulated as tobacco products under the FSPTCA, we
have very little information about the ingredients of liquids (purity, impurities or stability), or the approximate
exposure to harmful and potentially harmful constituents when using ENDS over the short-term or long-term. To
date, manufacturers are not required to publish what chemicals are in the ENDS solution, or to perform or reveal
results from systematic testing. Studies have demonstrated wide variability in design, operation, and contents and
emissions of carcinogens, other toxicants, and nicotine from ENDS.11 Depending on the brand, ENDS cartridges
typically contain nicotine, a component to produce the aerosol (e.g., propylene glycol or glycerol), and flavorings
(e.g., fruit, mint, or chocolate).12 Chemicals that pose health risks have also been documented in some ENDS,
including tobacco-specific nitrosamines, aldehydes, metals, volatile organic compounds, phenolic compounds,
polycyclic aromatic hydrocarbons, and tobacco alkaloids, but at much lower levels than in conventional
cigarettes.13 Furthermore, some ENDS manufacturers claim that the use of food flavorings is safe because they

2

 meet  the  FDA  definition  of  “Generally  Recognized  as  Safe (“GRAS”).14 However, GRAS status applies to
additives for particular food uses, and does not apply to products that are not food.
Although nicotine exposure in the absence of combustion is less hazardous than exposure to combusted
conventional tobacco products, nicotine itself is not without risk. 15,16 Nicotine is addictive.11 Nicotine exposure
during certain periods of development can impair the development of brain circuits and neurons, changing the
way the brain works.11,17 Pregnant women can transfer nicotine to their developing fetus, which can be toxic to the
fetus, leading to adverse pregnancy and infant outcomes.11 The evidence is also suggestive that nicotine exposure
during adolescence may have lasting adverse consequences for brain development, including cognitive maturation
and effects on working memory and attention.11,18,19,20 For non-smokers, nicotine is an acute irritant, potentially
causing headache, nausea, and discomfort; for former smokers, nicotine exposure can trigger cravings,
jeopardizing their abstinence.21,22
Because  of  the  risks  associated  with  nicotine,  the  2014  Surgeon  General’s  Report  concluded  that  “the  evidence  is  
sufficient to provide cautionary messages to pregnant women and women of reproductive age as well as
adolescents about the use of nicotine-containing  products  such  as  […]  electronic  cigarettes,  and  newer  forms  of  
nicotine-containing tobacco products, as alternatives to smoking.”11
II.

Toxicant Exposure to Non-Users

The health effects of ENDS may not be limited to users.23,24,25 ENDS  aerosol  is  not  “water  vapor.”  It  contains  
nicotine and can contain additional toxins, and thus, it is not as safe as clean air.26 Although some ENDS have
been shown to emit volatile organic compounds and dangerous toxins such as acetaldehydes, including acrolein,
these are generally emitted at much lower levels than by cigarettes.15 However, because there are hundreds of
manufacturers and no manufacturing standards, there is no way to ensure that all ENDS have acceptably low
levels of toxicants. Furthermore, some ENDS can be modified to deliver marijuana and other psychoactive
substances.27 Therefore, air containing ENDS aerosol is less safe than clean air, and ENDS use has the potential to
involuntarily expose children and adolescents, pregnant women, and non-users to aerosolized nicotine and, if the
products are altered, to other psychoactive substances.
All ENDS have the potential to involuntarily expose children and adolescents, pregnant women, and non-users to
aerosolized nicotine. In addition, FDA does not regulate the use of ENDS use, particularly in public places, and
the issue of involuntary exposure among bystanders to ENDS aerosol.
III.

Additional Hazards

ENDS use can result in accidents and other potential health hazards. CDC recently reported that the number of
calls to poison centers in the 50 states, the District of Columbia, and U.S. territories involving e-cigarettes rose
from one per month in September 2010 to 215 per month in February 2014, and 51.1% of these e-cigarette-related
poisonings were among young children ages 0–5.28 In the U.S., e-cigarettes account for a small proportion of total
tobacco product sales, but were involved in nearly 42% of combined monthly cigarette and e-cigarette poison
center calls in February 2014.29 Health-care providers; the public health community; e-cigarette manufacturers,
distributors, sellers, and marketers; and the public should be aware that e-cigarettes have the potential to cause
acute adverse health effects and represent an emerging public health concern.
An increasingly popular method of ENDS use is to self-mix the e-liquid—both the nicotine content and the
flavorings—prior to use. In this way, individuals can produce a customized ENDS product. There are also reports
in the news media about the potential for e-cigarettes to be altered to deliver other psychoactive substances such
THC, the active ingredient in marijuana.29,30 Importantly, the health risks of secondhand exposure to such selfmixed concoctions are unknown.
IV.

Impact of ENDS on Patterns of Tobacco Use

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 There are a range of potential beneficial and harmful impacts of ENDS on patterns of use of cigarettes and other
combusted tobacco products. The Surgeon General has stated that cigarettes and other combusted tobacco
products are the  “overwhelming  cause  [of]  the  burden  of  death  and  disease  from  tobacco  use  in  the  United  States”  
and  recommends  that  “rapid  elimination  of  their  use  will  dramatically  reduce  this burden.”11 The 2014 Surgeon
General’s  Report  notes  that  ENDS—in combination with rigorous surveillance and aggressive strategies to end
combusted tobacco use—could help complement strategies to eliminate combusted tobacco use by allowing
complete nicotine substitution among cigarette smokers.11
In the current context, cigarettes and other combusted tobacco products are widely available, heavily marketed,
inexpensive, and appealing to young people.11 In this context of widespread marketing and availability of
cigarettes and other combustible tobacco products, there are a number of potential adverse consequences of ENDS
on tobacco use patterns.11 Among youth, risks include: (1) aforementioned concerns about nicotine addiction and
consequences of nicotine on brain development, (2) initiation of the use of cigarettes or other combusted tobacco
products as a result of introduction to inhalation of nicotine delivered via ENDS, (3) exposure to ENDS marketing
and use that normalizes a behavior that looks very similar to smoking, and (4) use of combusted and
noncombustible tobacco products  at  the  same  time  (“dual  use”).9,13,31 The potential for ENDS to renormalize
tobacco use is of concern, because adolescents are particularly vulnerable to visual cues to smoke and to social
norms.4,31 Again, a recent study found that among never-smoking youth who had ever used an e-cigarette, their
intention to smoke conventional cigarettes was 22.4% higher than among youth who had never used e-cigarettes
(43.9% v. 21.5%, respectively).8 To advance the public health goal of preventing youth initiation of tobacco use,
youth should not be able to purchase or be exposed to marketing for any tobacco products, including ENDS.4,31
Among adults, potential adverse consequences include: (1) initiation of nicotine addiction among non-tobacco
users and potential for progression to combusted tobacco use; (2) long-term dual use among current smokers,
which may result in delayed quitting; and (3) relapse of smoking among former smokers.11
As noted above, current evidence shows that the majority of adults and youth who are using e-cigarettes are also
using conventional cigarettes; among current e-cigarette users, the proportion of current cigarette smokers was
72% during 2010/2011 and 76.8% during 2012/2013.1,5 This is of concern because only cutting down on the
number of cigarettes smoked does not significantly reduce tobacco-related health risks.32,33
Evidence of Effectiveness for Quitting Smoking
To date, no ENDS, including e-cigarettes, have been approved as a smoking cessation aid by the Food and Drug
Administration’s  Center  for  Drug  Evaluation and Research, and there is limited research on their effectiveness as
a cessation aid.22 There is currently no conclusive scientific evidence that ENDS promote long-term cessation,
especially at the population level.34,35,36,37,38,39,40 Currently, seven types of FDA-approved prescription and nonprescription smoking cessation products are available, including nicotine replacement therapies. These products
have been scientifically shown to be effective for smoking cessation, approved by the FDA for this use, and are
safe when used as directed. ENDS marketed as smoking cessation aids must be approved for such use by the FDA
Center for Drug Evaluation and Research.
ENDS Marketing
Although conventional tobacco products have been banned from television advertising for decades, ENDS are
now marketed on television and other mainstream media channels. Like the products themselves, marketing
claims  for  ENDS  vary  widely.  The  2014  Surgeon  General’s  Report  observed  that  ENDS  marketing  “has  included  
claims of safety, use for smoking cessation, and statements that they are exempt from clean air policies that
restrict smoking.”11 Moreover, some ENDS marketing uses tactics which the Surgeon General has found lead to
youth smoking, including: candy-flavored products; youth-resonant themes such as rebellion, glamour, and sex;
and celebrity endorsements and sports and music sponsorships.31 This is of concern because the Surgeon General
has found  that  “many  changes  in  tobacco  product  form  and  marketing  have  been  documented  as  efforts  by  the  

4

 tobacco industry to contribute to tobacco use and addiction by fostering initiation among young people; making
products easier and more acceptable to use; making and marketing products so as to address health concerns; and
making and marketing products to perpetuate addiction through the use of alternate products, when smoking is not
allowed or is socially unacceptable.”11
Smokefree Policies and ENDS
As mentioned earlier, air containing ENDS aerosol is less safe than clean air, and ENDS use has the potential to
involuntarily expose children and adolescents, pregnant women, and non-users to aerosolized nicotine and, if the
products are altered, to other psychoactive substances.41 Therefore, clean air—free of both smoke and ENDS
aerosol—remains the standard to protect health.
The majority of e-cigarette users also smoke cigarettes.1,10 Permitting ENDS use in public places could perpetuate
combusted tobacco use and, therefore, tobacco-related morbidity and mortality. For example, ENDS use in public
places could make it easier for smokers to sustain their nicotine addiction in public places, without switching
completely away from combusted tobacco use. There is no evidence to support any claim that policies that allow
ENDS use in public places result in smokers switching to ENDS completely. Additionally, because some ecigarettes are designed to mimic smoking, allowing ENDS use in places where smoking is prohibited could
complicate enforcement of smokefree policies and renormalize tobacco use.42
Conclusion
ENDS have a range of potential impacts on individual and population health, and significant questions remain
regarding their toxicity and impact on patterns of conventional tobacco use. In contrast, considerable and
conclusive evidence exists on the health harms of cigarettes and other combusted tobacco products among both
users and non-users. Moreover, the scientific literature supports the safety and effectiveness of FDA-approved
cessation aids when used as directed.
Given what we know about the harms of cigarettes and other combusted tobacco products, we should not lose
sight of the importance of tobacco prevention and control. However, given what we also know about nicotine
addiction, the harms of nicotine exposure—especially to the adolescent brain—and the fact that ENDS that do not
make therapeutic claims are not currently regulated, the scientific evidence supports a public health approach to
first  “do  no  harm.”  Ensuring  children  and  youth  do  not  have  access  to  ENDS,  preventing  ENDS  use  among  
children and youth, reducing the appeal of ENDS to children and youth, protecting nonusers from involuntary
exposure to ENDS aerosol, and ensuring smokers who want to quit have access to proven cessation methods are
all ways we can promote public health and protect vulnerable populations from potential harms.
Thank you for your attention to this important public health issue.

Thank you for your inquiry.
Sincerely,

Tim McAfee, MD, MPH
Senior Medical Officer
Office on Smoking and Health
Centers for Disease Control and Prevention
U.S. Department of Health and Human Services
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