What's the deal with "popcorn lung"???!
Question: I mean, come on!!!!
Answers: I mean, come on!!!!
People that work in the factories where artificially-flavored popcorn is manufactured were exposed to diacetyl in concentrations that caused a type of lung damage that is caused only by this chemical. So, there is no question about the effects of diacetyl when exposed to high concentrations. The people with lung problems (all but one) were exposed to the chemical in factories for 40 hours per week for many years in some cases before problems developed.
There's almost no way a consumer eating this popcorn in their homes could be exposed to the concentrations seen in the factories, but no food company wants to sell a product that has been identified in the news as a health risk, even if the risk is exaggerated; and the liability for the health problems for the factory workers could put a company out of business.
Also, it doesn't make sense for a company to start arguing with their customers about the safety of their product - its much more profitable to tell your customers that you want to ensure their safety and that you have taken steps to eliminate any health risk - great PR instead of negative PR. No one ever said that the rules have to be rational.