Diacetyl in electronic cigarettes, if even present at all, is many many times lower than cigarettes.
The other thing that people seem to ignore out of convenience is that the "popcorn lung" in the factory workers was caused from breathing POWDERED diacetyl, not liquid.  And they were breathing it for 8 hours a day in high concentration for YEARS.
That being said, the chances of getting popcorn lung from electronic cigarettes is virtually non-existent.  

The teens who are vaping are either former smokers, or they are vaping with no nicotine, as many studies already show, and has been proven time and again to NOT be a gateway to smoking.

Would you remove seatbelts from cars?  Helmets from motorcycle riders?  Vaping is all about HARM REDUCTION.  Nicotine is no more addictive or damaging than caffeine when removed from the combustion of burning tobacco.

Vaping saves lives, Public Health tells lies.  The ALA, ACS, and your state WANT you to keep smoking. They get $$$ from it.