(CN) — The Centers for Disease Control and Prevention said they’ve found a smoking gun in the search for what is causing death and illness from vaping THC products in the United States.

The CDC said in a teleconference last week that it has discovered the compound vitamin E acetate in the lungs of 29 people who became ill from inhaling vapor products containing THC. Vitamin E acetate is often used as an additive in the production of e-cigarette, or vaping, products.

As of Nov. 5, 2,051 cases of vaping-associated lung injury have been reported to CDC from 49 states, according to the CDC, and 39 deaths have been confirmed in 24 states and the District of Columbia.

In their new findings, the CDC studied lung samples from 29 patients in 10 states, and vitamin E acetate was found in all of the samples. THC, the psychoactive ingredient in marijuana, was found in 23 of the 29 samples, according to Dr. Anne Schuchat, the principal deputy director of the Centers for Disease Control and Prevention. Nicotene was found in 62% of the cases.

“These new findings are significant because we have detected a potential toxin” in the vaping illness outbreak, Schuchat said in the teleconference. “These findings provide direct evidence of vitamin E acetate at the primary site of injury in the lung.”

This is the first time that the agency has detected one chemical of concern in biological samples from patients with lung injuries from vaping, according to the CDC.

The agency recommends that people should not use e-cigarette, or vaping, products that contain THC, particularly from informal sources like friends, family or in-person or online dealers.

Schuchat said the CDC it is still studying the cause of the illnesses from vaping and there could be more than one chemical to blame for the illnesses.

She said the agency tested for a wide range of substances that might be found in e-cigarette or vaping products, including plant oils, petroleum distillates and terpenes, which are sometimes added to THC products.

“No other potential toxins were detected” in the testing, she said. “Additional investigations are ongoing.”

Vitamin E acetate is a known additive to a wide range of oral and topical skincare products, but the chemical usually does not cause harm when swallowed or applied topically. However, CDC research shows that when inhaled, vitamin E acetate can interfere with normal lung function.

“There is a big difference between putting vitamin E acetate on one’s skin or swallowing a vitamin E pill, and inhaling aerosolized vitamin E acetate,” Schuchat said. “Inhaling directly into the alveoli is a very different route of exposure that can cause local harm.”

Schuchat said states with dispensaries for marijuana set their own regulations for production and distribution “so it’s possible that vitamin E acetate may be included in some dispensary products in one state or another. It’s possible that it’s there intentionally and it’s possible it’s there unintentionally.”

In their study samples from the people who had a vaping-related illness, Schuchat said, “There seems to be a strong association from acquiring products from informal sources or online. The data are pointing to illicit supply chains,” but, she added, “I don’t think we know enough yet if we can take dispensaries totally out of the question. We’re taking a look at their regulation and quality control.”

Dr. Jim Pirkle, director of CDC’s division of laboratory sciences, said the testing of the samples from the lungs of the 29 patients was fairly broad, so it’s possible that there is more than one culprit in the 2019 spate of vaping illnesses.

“It’s possible we’ll come across other toxicants,” Pirkle said in the teleconference.

However, the common ingredient in the sick patients’ lung samples was vitamin E acetate and THC. While a small percentage of the samples did not have THC, there’s a reasonable explanation for that, Pirkle said. “THC is not something we would expect to be hanging around in the lung fluids,” Pirkle said.

“Like honey, vitamin E acetate is enormously sticky,” Pirkle said, “so when it goes into the lungs it does hang around.”

Schuchat said Friday’s report reinforces previous CDC recommendations that people should not use e-cigarette or vaping products that contain THC, particularly from friends or families or from online sources.

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