Yes they can but I do not know of a properly confirmed death directly from the use of sy thetic cannabinoids but they have certainly produced enough evidence that I believe they have contributed to the cause of death in some secondary way.
As you must know, no-one in history has ever died from smoking cannabis, it’s just not toxic enough in any amount. I’m gonna guess that marshmallow leaf and damiana, which are commonly used by vendors that aren’t scamming bastards, are just as non-toxic or close to and you would never even bother smoking these herbs because they have zero psychoactive effect. The only point of the green stuff is to massively reduce the amount oif cannabinoid you can smoke at once (the pure cannabinoid powders are active at sub-milligram levels) and also to remove any difficulty vaping powder but beliece me, reason 1 is by far the most significant and you are a complete fucking tit if you go vaping pure powders. Smoking too mjch weed will make you a bit white and shite for a while, overdosing on synthetic cannabinoids is a whole different animal though and I’ve read many stories of p[eople thinking they were dying, becoming almost paralyzed etc. They are very few and far between and normally occur due to some evil bastard loading a bowl for a newbie or something but it can and does happen.
To make incense, the pure powder is dissolved in a solvent and calculating varying ratios for different cannabinoids to the amount of solvent you need and the amount of leafy shit you’re gonna dump it on you have your incense.
