Popcorn lung, such a silly name for a truly severe disease. More appropriately known as bronchiolitis obliterans, this is a rare, life threatening disease where the airways of the lung are narrowed or closed due to the formation of scar tissue around them. This disease is usually seen when patients who have received a lung transplant begin to reject the organ. Their body attacks the foreign tissue and damages it. Often times, the only treatment is another lung transplant. The name popcorn lung disease came about in 2000 when former employees of a popcorn plant in Missouri started developing bronchiolitis obliterans. After much investigation it was found that the disease was linked to the inhalation of a specific chemicals used in the making of artificial butter flavouring for popcorn. The likely culprit, diacetyl, is used to give buttery flavour to many different foods. Two additional compounds (acetoin and 2,3-pentanedione) are also suspected to contribute to the disease. In factory’s that make microwaveable popcorn, workers are now required to respirators and there are maximum exposure limits put in place to protect them. The interesting thing about these chemicals is that they are harmless when eaten and only become hazardous when vaporized and inhaled.
E-cigarettes have become immensely popular in recent years with $3 billion being spent on them in 2013 and this number is expected to grow substantially over the next decade. E-cigarettes work by heating a solution that contains nicotine, glycerin, and various flavourings. These flavourings come in a wide variety of flavours, some of which sound like they are marketed directly at children (Cupcake, Fruit Squirts, Tutti Frutti). With so many flavour options, researchers at Harvard wondered if any of these flavourings contain diacetyl or other compounds that could damage the lungs of users. We could probably predict that which of the flavourings contain diacetyl since it is often used to give food or drinks a caramel, butterscotch, or pina colada flavour. It may come as a shock that that 76% of the flavours tested (39 out of 51) contained detectable levels of diacetyl, the culprit in popcorn lung disease. Additionally, acetoin and 2,3-pentanedione were detected in 45% and 90% of the tested flavours. These chemicals were found not only in ‘fruit flavoured’ liquids but also in liquids labelled ‘classic’ and ‘menthol’.
The current allowable exposure to diacetyl is 5 parts per billion for long term exposure over the course of 8 hours and 25 parts per billion for short term exposure (15 minutes). Let’s do some math, 5 parts per billion is equivalent as 5 micrograms per kg. If the average male weighs 80kg then their limit of exposure for 8 hours is 401ug of diacetyl. If you use Peach Schnapps flavouring in your e-cigarettes then you can only have 1 e-cigarette before you hit your limit for the day. Considering most people probably use their e-cigs throughout the day, it is likely that their exposure to diacetyl is much higher than is allowed for people who work in popcorn factory’s. We need much more research into someone’s daily exposure in order to make decisions about warning labels or regulations. The most frightening thing about these results is that some of these flavours are clearly marketed towards children. In fact, CDC estimated that 1.78 million children tried e-cigarettes in 2012. These compounds could be having profound effects on their lungs at such an early age. With the use of these devices rising, we could be facing a bronchiolitis obliterans crisis in 20-30 years like the COPD crisis now. As more and more research comes out, I’m sure that we will begin to see that these devices are not as safe as the company’s who make them lead us