Mixing Benadryl and alcohol can lead to amplified effects of intense drowsiness and sedation
This is, sadly, where things are going wrong - people are using chemicals like diacetyl in their liquids, in some cases as a base for mixing in other chemicals like THC (tetrahydrocannibinol - the psychoactive ingredient in cannabis) and this is causing the health issues that has skewed public perception of vaping, everywhere
Unfortunately, they've been taken off BBC iPlayer, and they're not available on NOW TV either
Later, studies and lawsuits showed that popcorn lung diagnoses were also made on workers in other manufacturing facilities that also use diacetyl, such as coffee bean processing plants, tortilla factories, pet food manufacturers, and other facilities that heated the dangerous chemical diacetyl