Updated April 20, 2015.

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

E-cigarette research is underway, but much still needs to be learned about this smoking alternative, including the effects it has on health over the long term.

We do know that traditional cigarette smoke contains upwards of 7000 toxins, including 250 poisonous and 70 cancer-causing chemical compounds. No level of secondhand cigarette smoke is considered safe to breathe.

E-cigarette emissions on the other hand contain far fewer toxins, in part because the vapor is not a byproduct of burning organic matter, but of heating the nicotine-containing liquid, which causes it to vaporize.

While e-cigarettes are less hazardous than traditional cigarettes, they're not harmless.  Let's take a closer look at the issues you should be concerned with if you're thinking about using e-cigarettes as a smoking alternative or a quit aid.

1.  Electronic Cigarettes are Not Regulated 

In the United States, tobacco products that are regulated must adhere to strict rules imposed by the U.S. Food and Drug Administration (FDA).  

These include: 

• Requiring manufacturers to register existing products and report product ingredients.
• New products must be reviewed and approved by FDA before going on the market.
• Claims that products offer a reduced health risk must be backed up by science that the FDA confirms and also agrees that the product offers a benefit to society as a whole.
• Tobacco products cannot be sold or given as samples to minors.  

Currently, regulated tobacco products include cigarettes, cigarette tobacco, smokeless tobacco, and roll-your-own tobacco. 

The FDA plans to extend their umbrella of control over more tobacco products soon.

  They are:  e-cigarettes, cigars, pipe tobacco,  nicotine gels, hookah tobacco and dissolvables. 

These products would be subject to the rules noted above and would also have to include health warnings, not be sold in vending machines at locations that are accessible to children, and adhere to minimum age and I.D. restrictions for sales. 

How Lack of Regulation Hurts Consumers

The current lack of regulation on e-cigarettes means that you can't trust that the product you're buying contains the amount of nicotine it claims to, or that it is produced with any quality control.  Pharmaceutical grade nicotine is used in all U.S. NRT products, but consumers can't count on that with unregulated tobacco products. 

Similarly, information on packaging regarding nicotine-free cartridges cannot be trusted.  They may, and often do contain nicotine.  This is especially bad if you're using e-cigarettes as a quit aid and trying to decrease nicotine gradually to zero.  

Finally, the quality of electronic cigarette devices themselves vary widely, which can affect vapor composition and toxicity.

2.  E-Cigarettes Contain Some Surprising Toxins

In a study reviewing available information about e-cigarette liquid, cartridges, vapor and exhaled emissions, authors noted the presence of a number of toxins in varying amounts, including formaldehyde, acetaldehyde, acrolein, o-Methyl benzaldehyde, acetone, volatile organic compounds, phenolic compounds, polycyclic aromatic hydrocarbons.  

While the amounts of these chemicals are much less in e-cigarettes than in traditional cigarettes, there is a risk of exposure to some of the same chemicals that are hazardous in cigarette smoke. 

TSNAs in e-Cigarettes

E-Cigarette liquid and vapor has been shown to contain TSNAs, a group of four chemical compounds that are thought to be some of the most potent carcinogens in tobacco products and tobacco smoke.  TSNAs are present in green tobacco and processed tobacco, including liquid nicotine. 

TSNAs are associated with lung cancer, oral and esophageal cancer, liver cancer and pancreatic cancer.  There is growing evidence that TSNAs may contribute to cervical cancer.

Heavy Metals in e-Cigarettes

Researchers studying e-cigarette emissions have identified chromium, a metal not present in cigarette smoke, as well as a number of other heavy metals that are, including zinc and lead.  The concentrations are much lower than in traditional cigarette smoke, but are not zero. Nickel is present in levels 4 times higher than in regular cigarette smoke.  

It appears that the metals probably come from the cartridges and that standardizing the quality of their construction may reduce these toxins.

3.  E-Juice is Poisonous

The "active" ingredient in e-cigarettes and the reason people use them is nicotine, and nicotine is a poison. It has been used in insecticides for years and is the addictive ingredient in both cigarettes and e-cigarettes.

According to a CDC study that reviewed calls to poison centers across the United States involving e-cigarette liquid containing nicotine, the incidence of accidental poisoning has skyrocketed in the last few years as e-cigarettes have gained in popularity. 

There was just one call per month pertaining to liquid nicotine in September of 2010 and 215 calls per month by February of 2014.  Approximately half of the calls involved children under the age of 5 being exposed to e-cigarette liquid, and 42 percent from people over the age of 20.

E-liquid comes in several sweet, candy flavors, which is appealing to kids. Poisoning occurs when nicotine-laced e-liquid is inhaled, ingested or absorbed through the skin or eyes.

In December, 2014, what may be the first death of a child due to liquid nicotine occurred in upstate New York state when a one year old who ingested liquid nicotine died soon after.  Local police didn't confirm that the liquid nicotine was associated with e-cigarettes, however it is likely.

And, earlier in 2014, a puppy in Britain got hold of an e-liquid cartridge and was dead within hours of chewing through it and ingesting a small amount of the liquid.  

4.  E-Cigarettes are a Smoking Alternative, Not a Quit Aid

It's probable that e-cigarettes will be a regulated product in the future.  When that occurs, it's also likely that a physician designed and endorsed regimen for smoking cessation using electronic cigarettes will eventually become available.  

When and if that happens, consumers will be able to count on a consistent level of manufacturing quality and nicotine quality and content.  They will also have a program for stepping down and off of nicotine completely, which is the purpose of any quit aid.

People are already using the e-cigarette as a means to quit nicotine altogether, and some are achieving success with it.  On the flip side, many e-cigarette users either transfer their addiction from tobacco to the device, or eventually go back to smoking traditional cigarettes full-time because they're still actively addicted to nicotine.

If you're thinking of using the e-cigarette to quit smoking, do some research first on the quit aids available on the market today, and have a discussion about them with your doctor, who can offer advice on the best choice for you. 

<sub>Sources:

U.S. Food and Drug Administration. FDA proposes to extend its tobacco authority to additional tobacco products, including e-cigarettes. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm394667.htm . Accessed March 2015.

British Medical Journal. Chemical Evaluation of Cigarettes.  http://tobaccocontrol.bmj.com/content/23/suppl_2/ii11.full . Accessed March 2015.

University of Southern California.  Secondhand E-Cigarette Smoke:  Healthier Than Regular Cigarette Smoke, But Still Contains Some Toxic Elements. http://pressroom.usc.edu/second-hand-e-cigarette-smoke-healthier-than-regular-cigarette-smoke-but-still-contains-some-toxic-elements/ . Accessed March 2015.</sub>