Most vapers are deeply concerned about the science involved with vaping. Although years of research have conclusively proven that smoking kills, the electronic cigarette industry is still in it's infancy and it's far too early to draw definitive conclusions about this seemingly “safer” alternative.

So far, the majority of research suggests that e-cigarettes are significantly less harmful than smoking, but there's a lot we don't know about the long-term impacts of inhaling vaporized nicotine.

Even though all of the ingredients used in electronic cigarettes are “FDA-approved” and widely considered safe for human consumption, inhalation (over extended periods of time) has never been fully studied. One of the ingredients that has raised the most concern is diacetyl.

The primary ingredients used in e-liquid, propylene glycol (PG) and vegetable glycerin (VG), have been studied for decades, are FDA-approved and widely considered safe in a variety of forms, including as a vapor. Other ingredients, including most of the flavorings, are also approved for a variety of uses, but diacetyl has caused a serious controversy and may pose some dangerous health risks.

What Is Diacetyl & Why Is It Used?

Diacetyl is found in many of the products we consume every day. It occurs naturally in the foods we eat such as butter, vinegar and honey. It's also produced during the fermentation process, present in alcoholic beverages and foods like cheese. The yellow-green liquid carries an intense buttery flavor and it's commonly used as a food flavoring. It's also recognized as “generally-safe” by the FDA.

In electronic cigarettes, diacetyl provides that creamy, buttery taste found in some e-liquid. Flavors such as butterscotch, custard and caramel are often produced with diacetyl, but despite being safe for ingestion, diacetyl and acetyl propionyl are thought to be hazardous when inhaled.

The Cause For Concern – Popcorn Lung

The reason diacetyl has become a health concern for vapers is a rare outbreak of the disease called bronchiolitis obliterans in the late 1990's. Also referred to as “popcorn lung,” it received the infamous name due to it's association with a microwave popcorn plant in Missouri. Over the course of several years, workers at the factory became sick with asthma and cold-like symptoms, which eventually worsened. As their symptoms advanced, thirty workers were diagnosed with the disease.

Although the cause was heavily debated, many scientists believed that the cases of “popcorn lung” were caused by diacetyl, used in popcorn to produce the buttery flavor that we all know and love. According to reports, diacetyl levels in the factory were three times higher than normal. Lung capacity was drastically reduced for the employees diagnosed with the condition and one eventually required a double lung transplant. That worker filed a lawsuit and was awarded $20 million by a jury.

In another case, a microwave popcorn customer was awarded $7.3 million in damages after contracting popcorn lung. Doctors claimed that the man developed the disease after inhaling fumes from microwaveable popcorn over almost a decade of habitual popcorn consumption.

Facts About Diacetyl & E-Cigarettes

It's important to note that NO CASE of popcorn lung has ever been attributed to e-cigarettes, but many believe that inhaling this chemical could lead to serious complications. In 2014 low levels of diacetyl (estimated at around 0.05%) were found in one e-liquid sample during a random test of VIP e-liquid in the UK. While the flavor (butterscotch) was immediately discontinued, the news made headlines and it raised serious concerns about the use of diacetyl in e-liquid.

Because of the known hazards associated with diacetyl, many companies proudly proclaim their products are “diacetyl-free.” While this may be true in some cases, short of independent lab testing there's no way to know for sure. The fact is, many e-juice companies DO NOT know if their products (or their ingredients) contain diacetyl, and some may be less than forthright, even if they know. Unfortunately, there are no standards for testing and no rules governing the use of diacetyl in e-liquid. Because of the growing concerns, more and more companies are seeking lab certifications, but independent lab testing is not currently required by e-juice companies or their suppliers.

Even though it may be extremely difficult to determine if an e-liquid is truly diacetyl-free, here are some facts that you should be aware of:

The quantities of diacetyl discovered in e-cigarettes have been, on average, 100 times lower than those found in traditional tobacco smoke. Another similar chemical, acetyl propionyl, has been discovered at levels 10 times lower than traditional cigarettes.

Although smoking kills hundreds of thousands of people each year, traditional cigarettes HAVE NEVER been associated with popcorn lung.

In a recent study conducted by leading e-cig researcher Dr. Farsalinos of the Department of Cardiology, Onassis Cardiac Surgery Center, over 159 samples were evaluated from 36 e-liquid manufacturers. 74.2% of those samples contained diacetyl! Even though the exposure levels were 100 times lower than tobacco, and as mentioned previously, smoking has never been tied to bronchiolitis obliterans or “popcorn lung,” it still raises concerns about the use diacetyl in e-liquid.

Should You Be Concerned?

To me, this topic seems heavily overblown by the media and I don't think vapers should be overly concerned about diacetyl. Since smokers have been inhaling this chemical for years and bronchiolitis obliterans has never been the result, it's likely that the amount of diacetyl required to cause popcorn lung it well beyond the levels found in cigarettes or e-cig vapor. Smoking has been proven to cause plenty of serious health conditions, but popcorn lung isn't one of them.

With that being said, you should certainly aware of the issue and try to make educated decisions about your e-liquid purchases. If you have the choice between a company that claims their products are diacetyl-free and one that does not, the diacetyl-free product is probably a better choice. It certainly doesn't hurt to be precautious, but many vendors that switch to diacetyl-free ingredients often replace them with products containing acetyl propionyl, which is virtually identical to diacetyl. If you're truly concerned, avoiding creamy, buttery and custard-like flavors is another way to reduce your exposure.

Because of the heavy scrutiny and elevated fears, more and more companies are lab testing their products and moving to diacetyl-free ingredients. In my opinion, it's only a matter of time before diacetyl (and acetyl propionyl) are completely removed from all e-liquid, whether the concerns are warranted or not. Be sure to ask, but you may or may not get a straight answer…

* Most companies featured on our website “claim” their products are diacetyl-free, including: Halo, Mt. Baker Vapor, NicQuid, Space Jam, Suicide Bunny, Virgin Vapor and more.