That part about BHO was a error on my account, not the study. It was meant in reference of pure THC or CBD extracts.

Also important to note that the Vitamin E acetate was mostly a problem in black market products.

But the terpenes they use as a diluent currently in legal/medical produced products result in harmful byproducts when vaped, as cited above.

BHO products also produce benzene and methacrolein. [1] There have been concerns raised about lipids being deposited in the lungs from the cuticle wax present in BHO products, but that area of study is in its infancy.