Breathing in giant clouds of nicotine vapor may not be such a good idea after all. Two new studies to be published in Nicotine and Tobacco Research show that burning nicotine fog juice at high temperatures produces formaldehyde.

The peer-reviewed studies, which were obtained by the Times, focus mainly on the large, refillable tank systems that are favored by Vape culture.

Dr. Goniewicz, an assistant professor of oncology at the Roswell Park Cancer Institute in Buffalo, said people using the systems “want more nicotine, but the problem is they’re also getting more toxicants.”

One of the studies honed in on the process of "dripping," which allows the e-cig user to drop a tiny amount of the e-cig liquid onto a very hot burner, rather than drawing from a larger tank of fluid.

But with dripping, the e-liquid heats with such intensity that formaldehyde and related toxins “approach the concentration in cigarettes,” said Dr. Alan Shihadeh, a project director at the Virginia Commonwealth University’s Center for the Study of Tobacco Products and an associate professor of mechanical engineering at American University in Beirut, who led the research.

While the results don't affect "traditional" e-cigarettes that come with pre-filled cartridges and lower-grade heating elements, the chief scientist for NJOY admitted to the Times that their product also produces formaldehyde, if at "significantly lower levels" than combustable cigarettes.

Roughly two weeks ago the FDA announced its proposed rules for e-cigarettes, and regulating the chemicals that are emitted from e-cig vapor isn't one of them, though the agency stressed that it will likely be evaluated in the future.