Unfortunately, popcorn lung can’t be positively diagnosed without doing a surgical lung biopsy, and sometimes not even then. Reading the accounts of studies done at the flavoring factories where known cases have been isolated, it’s clear that there is a spectrum of lung damage probably caused by diacetyl and other flavoring chemicals. Not every affected employee had severe permanent lung obstruction.
And the symptoms of BO are easily confused with those of chronic obstructive pulmonary disease (COPD), a far more common condition. Many lifelong smokers have COPD, which is a combination of emphysema and chronic bronchitis (most sufferers have both diseases). However, COPD develops slowly over years, while BO can develop rapidly, often within months after the chemical exposure that causes it.
The bottom line is that there has never been a diagnosed case of BO in a vaper. More importantly, there has never been a case in a smoker either. Why is that important? Because cigarettes contain diacetyl too, in much greater quantities than in vapor. In fact, cigarettes contain at least 100 times as much diacetyl as e-liquid.
That doesn’t mean it’s impossible that vapers (or smokers) can’t get popcorn lung from inhaling diacetyl. But as far as we know now, it hasn’t happened. And that probably means it isn’t likely. But that doesn’t stop news outlets from jumping on the diacetyl vape issue. Popcorn lung remains one of the most popular anti-vaping media topics.