Manufacturers were quick to claim that e-cigarettes were a safer alternative to smoking. Now, amid a glut of vape-related lung ailments, claims of hazards inherent to all vaping are coming just as quickly. Truth is, there are many questions, but few answers.

The e-cigarette is now two crazes in one: a product that over the last seven years has gained approximately 600 percent more users worldwide, and the latest panic.

The panic began roughly six months ago, when, as The New York Times reported in late August, physicians across the country began reporting cases of otherwise healthy people, mostly in their 20s or late teens, "showing up with severe shortness of breath, often after suffering for several days with vomiting, fever and fatigue. Some have wound up in the intensive care unit or on a ventilator for weeks." The Times quoted one doctor's belief that this was "becoming an epidemic."

Naturally, the Centers for Disease Control (CDC) got on the case, and before long it became apparent that a common denominator in at least the vast majority of the cases was the use of e-cigarettes, usually for the delivery of THC, the psychoactive ingredient in marijuana. The CDC, which labeled the condition "e-cigarette, or vaping, product use associated lung injury (EVALI)," provides updates on the latest data every Thursday. As of October 22, for example, there were 1,604 known cases nationwide⎯at least one in every state but Alaska⎯with 34 deaths.

But as the CDC itself notes, "At this time, FDA [i.e., the Food & Drug Administration] and CDC have not identified the cause or causes of the lung injuries in these cases, and the only commonality among all cases is that patients report the use of e-cigarette, or vaping, products." Nevertheless, the CDC not only "recommends that you do not use e-cigarette, or vaping, products that contain THC," but also notes that "[s]ince the specific compound or ingredient causing lung injury are not yet known, the only way to assure that you are not at risk while the investigation continues is to consider refraining from use of all e-cigarette, or vaping, products."

Better safe than sorry, right?

There's no arguing against the basic premise of the latter statement. If at least some e-cigs are in some way causing lung damage, the only way to be absolutely certain of avoiding that damage is to avoid e-cigs. But that's a far cry from our making a fully informed choice⎯and is very likely throwing out the baby with the bathwater.

For starters, as soon as you consider the fact that there are (according to the Los Angeles Times), 17.3 million vapers in the U.S., you don't need to have an advanced math degree to realize that only a tiny portion of vapers have suffered EVALI.

How tiny? Try 0.01%. That's one-thousandth of one percent, or slightly fewer than 1 out of every 10,000 vapers. By way of statistical comparison, you have a 50 percent higher chance of dying in a car crash than being affected at all by EVALI, never mind dying. Considering that vaping has been a widespread activity for over a decade, it stands to reason that only a tiny minority of vaping products can be causing EVALI⎯and probably products only recently making their way to market.

Moreover, despite the fact that the majority of patients presenting with EVALI have a recent history of THC-related vaping, there is likely no correlation between THC itself and EVALI. Although much more research on the long-term effects of marijuana is needed, to date there is little evidence linking moderate marijuana use to lung damage. For example, in 2012 Harvard Health, the online newsletter of Harvard Medical School, reporting on a study published in the Journal of the American Medical Association, noted that "smoking at a rate of one joint a day for as long as seven years doesn't seem to affect lung function adversely." And as researchers noted last year in the journal breathe, "cannabis smoking does not appear to be carcinogenic."

Additionally, vaporizing marijuana flower⎯i.e., heating it to a temperature high enough to vaporize the THC crystals on the plant without burning the plant material itself⎯has long been employed as a means to obtain the benefits of THC in a manner presumably less potentially harmful on the lungs than the traditional method of simply burning the entire flower and inhaling the smoke.

In other words, without the risk of making overstated claims about the safety of inhaling THC, it's safe to say that inhaling THC is not inherently linked to EVALI.

Almost certainly, then, based on the available evidence, the cause of EVALI is some additive or combination of additives present in a very small percentage of cartridges used for the delivery of THC via e-cigs or vape pens, which do not burn or vaporize the plant itself but use an oil distilled/extracted from the plant.

One of the early suspects was Vitamin E acetate, an oil form of Vitamin E, found present in nearly all cannabis products collected from EVALI patients nationwide. While Vitamin E is not known to be harmful when ingested or absorbed topically, prior to now its effects as an oil heated for inhalation were completely unknown. But as the Washington Post reported last month, those initial suspicions seem to have been supported by subsequent findings.

Nonetheless, as FDA spokesperson Michael Felberbaum told the Post, "No one substance, including Vitamin E acetate, has been identified in all of the samples tested." And although the majority of EVALI cases are tied to THC-related products, a not insignificant percentage are not. As Dr. Anne Schuchat, the CDC's principal deputy director, told reporters (as related by NPR) in late October, "The data do continue to point to THC-containing products as the source of the vast majority of individuals' lung injury. [But] there are continuing cases that do not report that history."

As has been widely noted, a large percentage of EVALI patients report buying vape cartridges off the black market, where regulation is completely nonexistent, presenting a greater likelihood that vape cartridge producers may be cutting their products with a variety of chemicals so as to increase their profit margin. "[... W]e don't know what the risky material or substance is," Schuchat said, "and THC may be a marker for a way that cartridges are prepared or the way devices are producing harm."

Inhaling any sort of nicotine product, in any form, is bad for your lungs. That is an example of something we know. At present we simply do not have anything resembling the same sort of knowledge concerning dangers that may be inherent to vaping. To be sure, avoiding e-cigarettes entirely will shield you from all possibility of EVALI; and there is ample evidence pointing toward alarming increases in youth smoking thanks to vaping technology (and the marketing thereof). But nicotine aside, the vaping devil that is EVALI is almost surely in the details.