Diketones and Popcorn lung

Discover everything you need to know about popcorn lung and the use of diketones in e-liquids.

A an x-ray withh a drawing of a lung with popcorn inside it to graphically demonstrate the concept of popcorn lung.

What is popcorn lung?

Popcorn lung made e-cigarette media headlines in December of 2015. Popcorn lung refers to the condition known as bronchiolitis obliterans that occurs when inhaled chemicals obstruct the smallest airways of the lungs due to inflammation and scarring. It is caused by breathing in toxic fumes or respiratory infections. The disease is not reversible; however, treatments can slow further worsening.

The term popcorn lung was coined by an incident that occurred during the 1990’s when workers in a popcorn factory had contracted bronchiolitis obliterans after prolonged exposure to the diketone diacetyl, the same diketone that was used in several creamy and buttery e-liquid flavours. It was in 2002 that the Centre for Disease Control and Prevention had documented eight cases of irreversible lung disease at a Missouri popcorn factory in the United States from 1992 to 2000.

What are diketones?

Diketones are molecules containing two ketone groups which are organic compounds composed of carbon atoms double bonded to an oxygen atom.  Diketones have been used in the food industry for decades as an additive for buttery and creamy flavourings in food. What many people don’t know is that many of the concentrates used in e-liquid flavours originate from manufacturers who specialised in creating food additives. Most food additives have a propylene glycol (PG) base, which is one of the two base liquids used in vape flavours. Due to this, diketones can be found in several creamy and buttery e-liquid flavours. Over the past few years, many of these flavouring companies have started to release e-liquid specific concentrates that are diketone free due to the increased demand from vape companies wanting diketones removed from their flavours.

What is diacetyl, acetyl propionyl and acetoin?

Diketones aren’t just one chemical compound. There are several different types of diketones. The main chemicals in e-liquids that are known as diketones are diacetyl, acetyl propionyl and acetoin.

The chemical structure of e-liquid additive Diacetyl

Diacetyl
Diacetyl is the particular diketone that made media headlines in regards to popcorn lung. It was found that in the 1990’s workers in a popcorn factory contracted bronchiolitis obliterans also known as popcorn lung. It is theorised with high probability that the cause was from inhaling high amounts of diacetyl over a prolonged period of time. Before this incident occurred nobody realised that inhaling diacetyl could be a cause of concern as it was heavily tested in food consumption with no issues.

It is important to understand that the levels of diacetyl that the popcorn factory workers inhaled were astronomically higher than the average amount of diacetyl traces found in e-liquids. Since the news around popcorn lung broke in late 2015, nearly all e-liquid manufacturers and flavour concentrate companies have removed all traces of diacetyl from their flavours.

The chemical structure of e-liquid additive acetyl propionyl.

Acetyl Propionyl and Acetoin
When many e-liquid manufacturers stopped using daicetyl in their flavours due to the media frenzy and negative press around popcorn lung, they turned to acetyl propionyl and acetoin as replacement diketones in creamy and buttery flavours. Unfortunately, acetyl propionyl and acetoin are not completely diacetyl free as they can catalyse into small trace amounts of diacetyl when vaped or in the manufacturing process. Many vape companies still use flavour concentrates containing acetyl propionyl and acetoin in their e-liquids. There is no regulation at present on having to declare the individual ingredients in e-liquids, due to this; it is hard to tell if a flavour contains diketones unless the manufacturer specifically says they do not. If you enjoy creamy flavours such as Tiramisu, Pineapple Pie, Mint Slice and Pavlova Parfait, we have a range of affordable premium e-liquids that are completely diketone free, check out our range of flavours here. [link to flavours]

Should you avoid e-liquids with diketones?

Acetyl propionyl and acetoin are still used in many e-liquid flavours on the market. The main reason that both of these diketones are still used in many flavours, is due to the enhanced taste they deliver in many creamy and buttery flavours. Some vapers absolutely love flavours that have diketones and refuse to switch, while many vapers choose to avoid flavours with any diketones as there has been no testing around whether acetyl propionly and acetoin is safe to vape.

It is best to understand the risks around whether you should avoid diketones in flavours or not. Firstly, it’s important to understand the popcorn lung case. It is clear that there was a spectrum of lung damage that was most likely caused by diacetyl and other flavouring chemicals; however, the amount of diacetyl the factory workers were inhaling on a daily basis was significantly higher than any vaper would ever vape. Secondly, diacetyl is found in cigarettes at a higher level than in e-cigarettes, however, the difference between combustion and vapour means that although it is a higher amount of diacetyl in cigarettes, it is not an apples to apples comparison. Lastly, the popcorn lung cases were specifically caused by diacetyl only, there have been no known cases of Acetyl Propionyl or Acetoin causing lung damage. If you want to avoid flavours that contain any diketones, check out our range of affordable, premium e-liquids. [link to flavours]

Do all e-liquids contain diketones?

Several creamy and buttery e-liquids contain diketones. Nearly all flavours no longer contain the diketone diacetyl that is linked to popcorn lung and instead use the diketones Acetyl Propionyl or Acetoin as replacements. Several e-liquid vendors and concentrate manufacturers are releaseing variants of creamy and buttery flavours that are completely diketone free and in some cases they taste as good if not better than there counterpart with diketones. If you want to buy affordable premium e-liquids that are completely diketone free, check out our range of flavours here. [link to flavours]