known dangerous substances...
Given all the dangers in life, interesting that some compound in liquid that "may" be dangerous bothers so many.
Water is a "known dangerous substance." So is oxygen.
Both are required for life too.
These compounds have unknown exposure limits. The current numbers are just guesses. We don't know the needed exposure and the time required for it to be an issue.
If it was as bad as being made out by some, then every worker in microwave popcorn factories would have the disease.
They don't, even among that group it's rare. (I'm not convinced, that Mr. Watson's disease was caused buy the popcorn. They just convinced a jury that it was. Jury verdicts are not science)
I've yet to see studies on exposure level over specific periods that give any indication of how dangerous it is.
Then follow that with info on the exposure from e-liquids with specific concentrations.
Maybe if you vape 10mL a day it's an issue, but is 2-3mL/day?
And if you change flavors, is 3mL a day, twice a week as bad as 1mL per day every day?
Just a lot of questions that are unanswered. While caution may be prudent, I see a lot of over reacting.
And once the scare tactics get used, it's nearly impossible to reverse the effects.
So in 5 years when they have better numbers and find that the quantity used in e-liquids if "safe" for at 3mL/day, is anyone going to use it again? Or will the stigma given now last forever?
History tells me that it'll last forever. (see DDT and CFC)