Then Sun read the subject line the same way that I did.
There are a bazillion (<--- technical term) tests that _could_ be run. Unless there's some particular indicator, there probably isn't a compelling reason to spend the money. I believe that Sun's tests were around the time of the big lead scare.
We haven't started asking how much TSNAs, benzene, formaldehyde, pestisides, cadmium, radioactive isotopes of lead and polonium, hydrogen cyanide, arsenic, ammonia, carbon monoxide, ... it contains. Why would we ask those questions? Because they are common elements in cigarette smoke.
It's hard to accept, but my gut tells me that it'd be hard for this to possibly be any worse, especially given the decades of study of PG use as an additive and even as an inhalant.