A study of THC vaping pens from both licensed and unlicensed dealers found that many bootleg pens contained Vitamin E and pesticides.
NBC News published the findings of their study done with CannaSafe, a marijuana testing company, on Friday. The study comes as a number of mysterious illnesses were being reported across the country believed to be linked to some form of vaping.
CannaSafe tested 18 different kinds of THC cartridges. Three were from legal dispensaries, and the remaining ones were from unlicensed dealers.
None of the legal cartridges had metals, Vitamin E, or pesticides. However, 13 of the 15 unlicensed ones were found to have Vitamin E and contained myclobutanil, which can turn into hydrogen cyanide when burned, according to the report.
Earlier this month, NPR reported that Vitamin E was being eyed as a possible reason for the outbreak in the illnesses.
Amid the outbreak, several states have come out with bans against flavored e-cigarettes–a different form of vaping than the THC cartridges.
Health and Human Services (HHS) Secretary Alex Azar also announced earlier this month that the Trump administration was finalizing a policy that would ban the sale of flavored e-cigarettes.
You can read all of NBC News’ story here.