They would treat it as nicotine use, even if the vape doesn't contain any. And yes, there are vapes that contain no nicotine--supposedly, those are for those who are either vaping for fun and not because they are trying to wean off tobacco, or those who are making their final step off cancer sticks. And no, they don't think of the safety aspect (vaping is safer than smoking, but not totally safe).
Other things they regard as bad include gambling (though I have heard sporadic reports where they are relaxing a bit on sporadic playing of scratch-off tickets, which is probably the worst form of gambling when it comes to addicting people). They also bad-mouth rap and heavy metal.
Then, it's up to the hounders in your area. Even without an explicit rule, there would be hounders that would treat vaping as smoking. It is the same with just about everything else--you have David Bowie's CD Diamond Dogs or Pinups, one congregation might say nothing but another might ban it. Someone might squeak about it, claiming to be stumbled, and there goes your records into the rubbish or MP3 files into the recycling bin. Or, playing a single scratch-off might result in no action in one congregation but another might form an instant judicial committee.
And they might threaten that, unless you stop, you will not qualify to go to Israel this spring on that stupid mission. For sure, they might disqualify you, at their discretion, from "privileges(??)" for any reason, rule or none. You could play this card in your favor--say, if they hound you to do Israel and you don't want to go, and you have one cut off Pinups and they squeak about it, tell them that if they keep hounding you to go, you are going to download the rest of that CD, and get Diamond Dogs as well. And, if that doesn't work, Led Zeppelin is next.