Bootleg marijuana vaping cartridges sold on the black market have been found to contain hydrogen cyanide, according to a report.

A cannabis testing facility in California analyzed a sampling of 18 cartridges containing THC — the active ingredient in marijuana — from both legal dispensaries and unlicensed dealers, NBC News reports.

No heavy metals, pesticides or solvents such as vitamin E were found in the legal products. But all 10 of the black market cartridges tested positive for pesticides and myclobutanil, a fungicide that can transform into hydrogen cyanide when burned, the analysis found.

“You certainly don’t want to be smoking cyanide,” the vice president of operations at CannaSafe, Antonio Frazier, told NBC News. “I don’t think anyone would buy a cart that was labeled hydrogen cyanide on it.”

Dr. Melodi Pirzada, a pediatric pulmonologist at NYU Winthrop Hospital on Long Island, said the presence of the fungicide was “very disturbing” and would have an extremely toxic effect on any user.

Pirzada was also alarmed by the presence of vitamin E acetate, a viscous solution sometimes added to marijuana oils, that was found in some of the samples acquired from unlicensed dealers, NBC News reports.

Sales of marijuana vaping products are reportedly down as much as 60 percent in some states as public health officials try to find out what’s behind a mysterious ailment that has sickened and killed some e-cigarette users.

State health officials in Oregon announced Thursday that a second state resident had died from a vaping-related lung illness.

That brings the national tally to 13, compared to the 12 fatalities announced earlier in the day by the Centers for Disease Control and Prevention, The Oregonian reports. Another 805 confirmed and probable cases have been identified in 46 states, the CDC said.

Some 77 percent of people impacted by the outbreak have reported using products containing THC, the federal agency announced Friday. The exact cause of the illnesses remains unclear, but CDC officials advised people to stop using e-cigarette or vaping products, especially those that contain THC.