Does vaping cause popcorn lung?

According to Cancer Research UK, there is little to no evidence linking e-cigarette use to “popcorn lung” (bronchiolitis obliterans). In 2015, several studies sparked widespread media attention after suggesting a connection between inhaling a chemical called diacetyl and this rare lung condition. However, the documented cases of popcorn lung were almost exclusively found among factory workers in popcorn manufacturing facilities, where prolonged occupational exposure occurred. These cases were not linked to e-cigarette use.

As a precautionary measure, vaping manufacturers and flavour producers have since removed diacetyl from their products. In 2016, diacetyl was fully banned in the UK under the EU Tobacco Products Directive (TPD). Today, most vape liquids are completely diacetyl-free, and any that do contain trace amounts typically have levels hundreds of times lower than those found in cigarette smoke.