Federal health officials have identified vitamin E acetate in the lung fluids of 29 people sickened in the outbreak of unsafe vaping-related lung injuries.
While the CDC's initial warnings included telling people to avoid "e-cigarettes", they have finally updated their message to state that by e-cigarettes they really mean vaping products, and that right now they're specifically concerned about THC vapes.
It isn't clear how widespread the use of vitamin E acetate is in e-cigarette and vaping products.
"For the first time, we have detected a potential toxin of concern, vitamin E acetate, from biological samples from patients", Dr. Anne Schuchat, the CDC's principal deputy director, said at a news briefing, according to the New York Times.
In the CDC analysis, THC was detected in 23 of 28 patient samples of lung cells, including from three patients who said they did not use THC products.
The study, which examined lung fluid from 29 patients who either fell ill or died after vaping, discovered that every specimen contained vitamin E acetate - an oil derived from the vitamin.
Vitamin E acetate is a common additive in many cosmetic and food products; it is considered safe when applied to the skin or consumed, but evidence indicates that it may be risky when inhaled. Numerous injured also reported using counterfeit or black-market products containing THC, notably those marketed as "Dank Vapes".
The chemical has shown up in tests in other labs, too, including a U.S. Food and Drug Administration lab in Cincinnati that found vitamin E acetate in half of the more than 400 THC samples. But none of them were found in the lung fluid samples. THC, the active ingredient in marijuana, was found in the majority of samples and nicotine was found in about half of samples.
Officials tested the samples for a variety of substances, including mineral oils, plant oils, diluent terpenes, cannabinoids, and nicotine, as well as a common component of lung secretions. Past research from the CDC indicates that when consumed or applied topically, vitamin E acetate isn't harmful.
He described vitamin E Acetate as "oily - not kind of a common oil, but it's an oily substance".
The CDC's study was published today in the Morbidity and Mortality Weekly Report (MMWR). Some earlier work by non-CDC researchers has suggested that it could interfere with normal lung function when inhaled, Schuchat noted to reporters Friday.
The findings reinforce the agency's recommendation that people should not use vaping products containing THC, particularly those obtained from informal sources. It usually does not cause harm when swallowed, but its effects when inhaled have not been extensively studied.