Skip to main content

How Safe Are Electronic Cigarettes? Not Everyone Agrees

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


My friend lit up her electronic cigarette during intermission when we were in line for a bathroom at a Broadway theater. People in the line looked at her disapprovingly. She responded quickly: “I am not smoking. It’s only water vapor.” That’s the argument that the e-cigarette industry makes, and it is clearly one that my friend wants to believe. Her response put a stop to any questions about second-hand smoke. Nobody else said anything. Maybe nobody wanted an argument on a night out for theater or maybe people knew too little to comment confidently. She waited for a bathroom stall and continued smoking.

While questions about electronic cigarettes stayed below the surface in the ladies room, they are hotly debated in the world of tobacco control and public health. There are concerns about the exact benefits and potential harms of electronic cigarettes, secondhand smoke, and air quality. Proponents see e-cigarettes as a safer alternative to traditional cigarettes, but skeptics question how safe they really are, both for users and people exposed to them as second-hand smoke. So far, they have been manufactured and distributed without oversight, data, or proof that they are a bridge to quitting more toxic cigarettes. Also, many experts question the industry line that just water vapor is released when users light up.

Product Regulation Considered


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


In today’s Lancet Respiratory Medicine, two commentaries put forth opposing views on the question of regulating electronic cigarettes as medical devices. Nathan K. Cobb, MD, and Caroline O. Cobb, from the Department of Pulmonary and Critical Care Medicine, Georgetown University Medical Center, Washington, DC, warn: “Without oversight or consumer safety regulations, the manufacturers of ENDS produce products that are more widely available, much cheaper, and might contain more nicotine and contaminants than competitor products manufactured by pharmaceutical companies.”

Cobb and Cobb want regulation. They frame the issue this way: “The question should be what regulatory system will get safe and effective refined nicotine products into the hands of more smokers and promote elimination of the most lethal combusted products?”

In the second commentary Peter Hajek, Director of the Tobacco Dependence Research Unit at the Wolfson Institute of Preventive Medicine, Queen Mary University of London, UK, and colleagues, argue that regulation will stifle innovation, the development of better healthier electronic cigarette designs, and hinder competition of e-cigarettes against more toxic traditional cigarettes.

Product regulation is only one part of the story. It is what the Food and Drug Administration can address. Local governments will have to decide where people can use e-cigarettes, whether air quality statutes should issue standards.

E-Cigarette Use Patterns

I asked Stanton Glantz, PhD, Professor of Medicine at the Center for Tobacco Control, University of California San Francisco, and leading tobacco control expert, to comment on the Lancet Respiratory Medicine papers, and address concerns about the use and proliferation of e-cigarettes.

Q: What did you think about the opinions on e-cigarette regulation in Lancet Respiratory Diseases?

A (Glantz): The pieces were focused on e-cigarettes as products. They did not address what effect e-cigarettes have on use patterns. We’ve found very high levels of dual use [traditional cigarettes along with e-cigarette use]. Very few people have switched away from cigarettes or managed to use them as a bridge to eventually go off cigarettes. While many people believe e-cigarettes helped them quit smoking, neither of the available population-level studies showed such an effect. One showed e-cigarette users and nonusers quitting conventional cigarettes at the same rates, the other showed e-cigarette users being less successful at quitting.

Q: Where do the authors stand on harm reduction and addiction?

A (Glantz): The articles reflect the polarization in the public health and tobacco control communities. The optimists - the harm reduction people (in this instance Hajek et al.)-- essentially believe that electronic cigarettes are much less dangerous than traditional cigarettes and so their use should be encouraged. The pessimists (Cobb and Cobb) see electronic cigarettes as an addictive drug that, without regulation, are not going to market in a way that will disrupt the primary profit stream of cigarettes, and so could end up just keeping people smoking conventional cigarettes.

There’s an assumption among the harm reduction people that if you could snap your fingers and get every smoker to switch to e-cigarettes, you’d be ahead. One problem is that you can’t do that. While the industry uses social media and the internet to present e-cigarettes as a miracle way to quit, as noted above, no independent studies show that e-cigarettes actually help people quit. They may even discourage quitting.

Q: In what camp do you put yourself?

A (Glantz): I am a realist who is driven by data. I started out agnostic on e-cigarettes. While there is not a lot of information available now, what is there is pointing to dual use and e-cigarettes impeding quitting cigarettes. All the big cigarette companies are now getting into this market. They are not going to market those products in a way that jeopardizes the cigarette market.

Q: Do you agree with the harm reduction people that e-cigarettes are a safer alternative for smokers?

A (Glantz): If smokers switched entirely from conventional cigarettes to e-cigarettes, no one started smoking because of e-cigarettes, and e-cigarettes did not discourage quitting, smokers would be better off.

Contrary to marketing claims, e-cigarettes do not deliver “pure nicotine” and “harmless water vapor.” In 1986, California passed a ballot initiative known as Proposition 65, which was intended by its authors to protect California citizens and the State’s drinking water sources from chemicals known to cause cancer, birth defects, or other reproductive harm, and to inform citizens about exposures to such chemicals. Annually, the Governor must publish a list of chemicals known to the state to cause cancer or reproductive toxicity. Ten compounds that are on the Proposition 65 list have been identified in mainstream (MS) or secondhand (sidestream/SS) e-cigarette vapor (See table)

Ten Compounds Found in E-cigarette Mainstream* or Secondhand Smoke**, Also on California's Proposition 65 List

* Acetaldehyde (MS)

* Benzene (SS)

* Cadmium (MS)

* Formaldehyde (MS, SS)

* Isoprene (SS)

* Lead (MS)

* Nickel (MS)

* Nicotine (MS, SS)

* N-Nitrosonicotine (MS, SS)

* Toluene (MS, SS)

*MS - mainstream smoke

** SS - secondhand smoke

Credit: Stanton Glantz, PhD, Adapted from Gonewicz ML, Knysak J, Gawron M, et al. Levels of selected carcinogens and toxicants in vapour from electronic cigarettes. Tob Control. doi:10: 1136/tobaccocontrol-2012-050859 and Schripp T, Markewitz D, Uhde E, et al. Does e-cigarette consumption cause passive vaping? Indoor Air 2013; (1):25-31.

Q: Do you think that, based on what we know, we should ban e-cigarette use in the same places that we ban cigarettes?

A (Glantz): Yes. Even though e-cigarettes are less polluting than conventional cigarettes, they still are putting a variety of volatile organic compounds, heavy metals, fine particles and other toxins into the air. Regardless of the concentrations, there is no justification for reintroducing these toxins indoors after we spent 30 years getting rid of them.

Q: Do you think that any regulatory entity has taken the lead with a strong policy protecting the public’s health with e-cigarettes? What would such a policy look like?

Q: The FDA has the ability to regulate e-cigarettes as products and should do so. The reality is, however, that meaningful regulation is probably years away because the tobacco and e-cigarette companies (that are more and more the same companies) will do everything they can to slow it down or stop it, including through the courts.

Where you can smoke e-cigarettes is a matter for local and state governments, who are already starting to act to include e-cigarettes in clean indoor air laws.

Laura Newman writes about medicine, health policy, and clinical outcomes research. She has a long-term interest in healthcare reform and what matters to patients. She has written news in health and medicine in peer-review journals, on the web, and for newsletters. Laura blogs at Patient POV, is active on twitter at @lauranewmanny, and she is especially interested in integrating patients into health reform efforts.

More by Laura Newman