[rgejman]

I remain cautiously pessimistic because there are two main possibilities: (1) there is one product (or a series of products manufactured/purified in the same way) that causes respiratory failure in many or all users, (2) all vaping products have a low level risk of causing respiratory failure. I don't think there is enough data to make a conclusion yet, but I am worried this will end up being a low-level persistent problem with vaping products—bootleg or not—for the rest of our lives.

Maybe the culprit truly is dirty oil based extraction of THC... but if so, that will remains a problem for as long as there is no regulation of the official market as well as an operating black market.

OTOH we may end up with a situation like we have in the world of muscle builder / hormone supplements where most people are fine but some users get really sick (e.g. deer hormones sold at regular stores causing severe kidney injury), but not enough of them get sick to get the CDC/FDA involved. I've seen those cases in the hospital and the patients are always confused as to how this could happen because they got the supplement from a vitamin store.

With respect to some of the European posters below who have been using vape products for years: I would not be surprised if there were health consequences to those devices that had not been identified in Europe. The US has one of the best disease identifying-apparatuses in the world (the Centers for Disease Control) and a tradition of surveillance and reporting that is unparalleled. If a substance is harmful to health, it's got a better chance of being found here than anywhere else.