Tbh its not if you only cape pure stuff, but the extraction process, and even more so the additives companies legally can add after definitely are.
A lot takes advice from nic gaping, which is pretty much just making a chemical soup solely to making smoking quicker and simpler.
Stick to good extraction methods, and a concentrate vape instead of mixed then you should be good (CO2 instead of butane, diamonds, distillates are all good)