Scientists may have gotten closer to figuring out what’s causing the “mysterious vaping illness” that has hospitalized over 200 people and killed at least two. Chemical analyses have now revealed a potential culprit: vitamin E acetate, also known as tocopheryl acetate, a form of vitamin E used to make lotions and other skin products.

How’d they determine this? Investigators recently realized the vaping illness was likely caused by vaping marijuana products. Specifically, black market vapes. But we already know that weed doesn’t cause this illness, otherwise we would see it in people who smoke — but don’t vape — their weed, too. 

So, after running dozens upon dozens of chemicals tests, investigators found one principle compound that’s present in some weed vapes but not in nicotine vapes, and that compound was vitamin E acetate, the Washington Post reported. Additionally, the compound was found in almost all vape samples collected from lung illness patients in the New York area.

Gallery — Here’s What Fake Vape Cartridges Actually Look Like:

Vitamin E acetate is considered fairly harmless, so long as it’s only applied to the skin or ingested orally as a nutritional supplement. In fact, as noted by David Downs at Leafly, you can buy entire jugs of the stuff online, hella-cheap, free of any regulatory restrictions. But scientists don’t know what the compound does if it’s inhaled, because it’s not a common vape additive outside of the illicit vape cartridge markets.

“The cases of pulmonary illnesses associated with vaping are continuing to rise across New York State and the country,” New York Health Commissioner Dr. Howard Zucker wrote in a public statement on Thursday. “We urge the public to be vigilant about any vaping products that they or any family members may be using and to immediately contact their healthcare provider if they develop any unusual symptoms. In general, vaping of unknown substances is dangerous, and we continue to explore all options to combat this public health issue.”

Most states, including New York, ban vitamin E acetate in legal vaping products. The chemical is only found in black market vapes, including candy-flavored vapes that aren’t infused with weed.

What’s the takeaway? Illicit vape producers work under the radar, and their products don’t undergo any testing until people start dying from them. Stick to the legal products, since those undergo mandatory testing, and licensed producers are subject to heavy fines or criminal prosecution if they cheat the system.

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