NBC commissioned a California cannabis testing facility to look at 18 different vaping cartridges containing THC, the psychoactive chemical found in marijuana. They did testing on products from legal dispensaries and unlicensed dealers. The lab they used, CannaSafe, tested 10 black market cartridges for pesticides, and all 10 came back positive. Specifically, they contained the ingredient myclobutanil, which can turn into hydrogen cyanide when burned, NBC reported.