For several years now many smokers have quit buying cigarettes and switched to e-cigarettes, believing them to be a healthier alternative to smoking without having to give up nicotine altogether.  However, according to a new study, the vapor produced by an e-cigarette can contain cancer-causing formaldehyde at levels up to fifteen percent higher than regular cigarettes.

Researchers found that e-cigarettes that operate at high voltages produce a vapor that has large amounts of formaldehyde-containing chemical compounds.  These compounds could pose a risk to users who increase the voltage on their e-cigarettes to increase the delivery of vaporized nicotine, the co-author of the study James Pankow says.

"We've found there is a hidden form of formaldehyde in e-cigarette vapor that has not typically been measured. It's a chemical that contains formaldehyde in it, and that formaldehyde can be released after inhalation," Pankow says. "People shouldn't assume these e-cigarettes are completely safe."

Health experts have known for some time now that formaldehyde and other toxic chemicals are present in cigarette smoke.  In the beginning, scientists hoped e-cigarettes would be free of these dangers because they lack the presence of fire to create the toxic chemicals. 

But newer versions of e-cigarettes can allow the user to operate them at very high temperatures to allow for quicker deliver of the nicotine.  This heat dramatically increases the creation and release of the toxic compounds, and now researchers are saying these levels are something to be aware of.

"The new adjustable 'tank system' e-cigarettes allow users to really turn up the heat and deliver high amounts of vapor, or e-cigarette smoke," lead researcher of the study from Portland State University, David Peyton says. Users open up the devices, put their own fluid in and adjust the operating temperature as they like, allowing them to greatly alter the vapor generated by the e-cigarette.

The American Vaping Association has argued that the new study is flawed because users wouldn't operate their e-cigarette at such high voltages.

"When the vapor device was used at the realistic setting of 3.7 volts, levels of formaldehyde were similar to the trace levels that are released from an FDA-approved [smoking-cessation] inhaler," association President Gregory Conley says. "However, when the researchers increased the voltage to 5 volts and continued to have their machine take three- to four-second puffs, this caused extreme overheating and the production of formaldehyde."

E-cigarettes still remain unregulated, and the American Cancer Society believes these new findings highlight the need for regulation of the industry.

"This study shows how little we know about toxic exposures that can result from using any one of the many different available types of e-cigarettes at different heating levels," said Eric Jacobs, the cancer society's strategic director of pharmacoepidemiology. "Until these things are monitored and regulated, there's a real potential risk for unexpected exposure to toxic chemicals."

"We really don't know what kind of exposure the users might get when using any particular product at any particular heating level."