Thursday, July 30, 2009

Comparison of Carcinogen Levels Shows that Electronic Cigarettes are Much Safer Than Conventional Ones

The FDA last week condemned electronic cigarettes on the basis that an FDA laboratory detected carcinogens (tobacco-specific nitrosamines) in the cartridges of several electronic cigarette manufacturers. The FDA held a press conference in which it attempted to scare electronic cigarette users into discontinuing e-cigarette use (and therefore a return to conventional cigarette smoking). In addition, a number of anti-smoking groups, including the Campaign for Tobacco-Free Kids and American Lung Association, have called for a ban on these products due to this carcinogen scare.

The FDA (and the anti-smoking groups), however, failed to do three important things:

First, they failed to disclose the levels of tobacco-specific nitrosamines that were detected in the electronic cigarette cartridges.

Second, they failed to test the control product (a nicotine inhaler) to determine the carcinogen level in that product.

Third, they failed to report the tobacco-specific nitrosamine levels in conventional tobacco products, including cigarettes.

The Rest of the Story

Because of the FDA's and the anti-smoking groups' omissions, there is a need to get the rest of the story out there to the public. And here it is, in this table:

Maximum Tobacco-Specific Nitrosamine Levels in Various

Cigarettes and Nicotine-Delivery Products

(ng/g, except for nicotine gum and patch which are ng/patch or ng/gum piece)







Electronic cigarettes (2)






Nicotine gum (1)


Not detected

Not detected

Not detected


Nicotine patch (1)

Not detected


Not detected

Not detected


Swedish snus (3)


Winston (1)






Newport (1)






Marlboro (3)


Camel (1)






Skoal (1)






Marlboro (1)







  1. Stepanov I, Jensen J, Hatsukami D, Hecht SS. Tobacco-specific nitrosamines in new tobacco products. Nicotine & Tobacco Research 2006; 8:309-313. (Link)
  2. Laugesen M. Safety Report on the Ruyan e-cigarette Cartridge and Inhaled Aerosol. Christchurch, New Zealand: Health New Zealand Ltd, 2008. (Link)
  3. Wahlberg I. Tobacco-specific Nitrosamines in Unburnt New Zealand Tobaccos. Report to Health New Zealand Ltd. Swedish Match, 2004. (Link)

As these data show, the level of tobacco-specific nitrosamines present in electronic cigarettes is at the trace level. It is measurable in parts per trillion (nanograms per gram). It is comparable to the nitrosamine levels in nicotine replacement products which are approved by the FDA.

In contrast, the level of tobacco-specific nitrosamines present in tobacco products are 300 to 1400 times higher. On a weight-for-weight basis, Marlboro has 1400 times higher the level of tobacco-specific nitrosamines than an electronic cigarette cartridge. And keep in mind that these represent the levels in the cartridges and cigarettes, not in the tobacco smoke or e-cigarette vapor which are directly inhaled. Because of the much higher temperatures generated in tobacco combustion compared to propylene glycol vaporization, the delivery of these carcinogens into the vapor is expected to be much lower than into the tobacco smoke.

Moreover, there are approximately 56 other carcinogens that have been identified to be present at high levels in tobacco smoke, while there are no other carcinogens that have been identified to be present in electronic cigarettes.

Based on these data, and upon knowledge that the conventional cigarette contains at least 10,000 other chemicals, including known toxins and carcinogens, while the electronic cigarette does not, there is exceedingly strong evidence that electronic cigarettes are much, much safer than conventional ones.

This does not mean that there are not issues that need to be addressed with electronic cigarettes. The diethylene glycol that was present in one cartridge tested suggests that more widespread and systematic testing should be done to identify the extent of this problem. Testing is also necessary to determine whether the diethylene glycol actually makes it into the e-cigarette vapor/mist. The problem should be able to be addressed easily, since high-grade propylene glycol - which is almost entirely free of diethylene glycol - is readily available.

Appropriate procedures also need to be in place, if they are not already, to ensure that electronic cigarettes are not available to minors.

However, what this calls for is the FDA working with the electronic cigarette manufacturers and distributors to study the product and address the identified problems. It does not call for the FDA to ban the product or pull it from the market.

This research is not the only work that has established that electronic cigarettes are much safer than conventional cigarettes. Research conducted by Dr. Murray Laugesen and Health New Zealand Ltd. reveals that the toxic emissions score for electronic cigarettes is much lower than that of conventional cigarettes. In fact, the toxic emissions score - which is a score based on the levels of 59 priority toxicants - was zero for electronic cigarettes. In contrast, it was 126 for Marlboro and it was no lower than 100 for any brand of conventional cigarette tested.

Note that the above study actually tested the electronic cigarette vapor. This is the most relevant test, because it determines what the user actually inhales. The study found no more than trace levels of any of the 59 priority toxicants.

The study concluded: "Ruyan® V8 nicotine e-cigarette users do not inhale smoke or smoke toxicants. The modest reductions recommended in 2008 by WHO’s Tobacco Regulation committee for 9 major toxicants in cigarette smoke, in line with Articles 9 and 10 of the FCTC (WHO Framework Convention Tobacco Control treaty), are already far exceeded by the Ruyan® e-cigarette, as it is free of all accompanying smoke toxicants. Absolute safety does not exist for any drug, but relative to lethal tobacco smoke emissions, Ruyan e-cigarette emissions appear to be several magnitudes safer. E-cigarettes are akin to a medicinal nicotine inhalator in safety, dose, and addiction potential. E-cigarettes are cigarette substitutes. If they can take nicotine market share from cigarettes, and that is the big question, they will improve smoker and population health. They may also have a secondary role as medicinal nicotine inhaler quitting aids. Further trials of acceptability, addiction potential, clinical safety, and quitting efficacy are needed."

It should also be noted that there is preliminary research which provides laboratory evidence that electronic cigarettes are as effective as nicotine replacement products for short-term smoking cessation (i.e., these products have been shown to provide relief of cigarette cravings at a level comparable to nicotine replacement products). This research found that electronic cigarettes are actually preferable to a nicotine inhaler in terms of helpfulness, pleasantness, and ratings of whether the smoker would use the product and recommend the product. Given the overwhelming anecdotal evidence of the effectiveness of e-cigarettes for smoking cessation, formally studying the longer-term effectiveness of these products is a research priority.

Electronic cigarettes have the potential to be a life-saving intervention for millions of smokers. The FDA and the anti-smoking groups need to embrace this product and support the appropriate testing, not remove it abruptly from the market and sentence over a million e-cigarette users to disease and even death by a return to conventional cigarettes.

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