After being contacted by BuzzFeed News, the platform took down some of the videos. Vaping-related injuries continue to climb by the day.

Screenshots via YouTube

As health agencies scramble to control a rash of mysterious vaping-related lung injuries, YouTube is playing host to dozens of videos that offer step-by-step instructions on how to make black-market THC vape oil. Some of these videos, which are rife with safety hazards, including the use of potentially harmful chemicals, have been viewed millions of times. The proliferation of the videos underscores the challenge of pinning down the cause, or causes, of the outbreak. Nearly 1,300 lung injuries, including 26 deaths, have been confirmed in every state but Alaska, the CDC said Thursday, and in 76% of cases, patients have reported vaping THC products. Contaminants in the vaping liquids, such as vitamin E acetate used as a “thickener,” have come under suspicion as culprits. “I cannot overstate the seriousness of these lung injuries," Anne Schuchat, principal deputy director of the CDC, said in a news conference on Friday. In response to the outbreak, the CDC and the FDA have urged people to stop vaping THC. "Some new, risky practices in preparation of these materials" may be causing the illnesses, Schuchat added. In 10 videos reviewed by BuzzFeed News, hosts transform cannabis flowers into oils with the help of casserole dishes, spatulas, mason jars, ovens, hair straighteners, and equipment and chemicals bought online. Their how-to guides have drawn audiences in the hundreds of thousands, and as high as 1 or 2 million in some cases. (BuzzFeed News is not linking to these videos in this story.) “We’re going to show you today how to make a marijuana-infused e-liquid, so you can vape it as you would in a normal cigarette,” said a man in a video titled “How To Make Marijuana E-Cig Liquid / E-liquid” (which has received 1.4 million views) on the channel Lets Vape, which has north of 24,000 subscribers and appears to be based in Europe. “Now it’s very simple. We have a kit ready that will make this really, really easy for you.” But the process is in fact complex and can also be unsafe, according to experts who reviewed the videos. Much can go wrong along the way, from pesticides in cannabis to heavy metals in cartridges — all of which could go undetected by the average person. Some of the solvents used in the instructional YouTube videos could also be toxic if overheated, experts said. "There is nothing safe about video demonstrations on how to create vaping liquids, whether they are nicotine or THC as both have been proven to be harmful — in kitchens or other environments," Lawrence Weinstein, chief medical officer of the American Addiction Centers, told BuzzFeed News by email. "The sheer number of these videos are troubling." Immediately after being contacted by BuzzFeed News, YouTube took down some of the flagged videos, but did not respond to questions about why those videos violated its rules and others did not. One of the videos belonged to Lets Vape, which could not be reached for comment because it does not provide any contact information.

“YouTube is a community site with clear policies that prohibit inappropriate content, including material that depicts minors smoking or misusing any type of illegal or regulated substances,” YouTube spokesperson Farshad Shadloo said by email. “From a content policy perspective, we generally do not restrict/prohibit content that depicts vaping on our platform — unless it is in the form of a challenge or it is a depiction of minor vaping.”

Dan Vergano / BuzzFeed News

Many of the THC products implicated in the recent outbreak were bought on the black market from brands of ambiguous origin, like Dank Vapes, and through hard-to-trace sources like friends, dealers, and street vendors, according to state health agencies in New York, Illinois, and Wisconsin. Around 13% of patients claim they had only vaped nicotine products, though some may be reluctant to admit to using THC.

Social media is also playing a role in the crisis, health professionals acknowledge. On Tuesday, the head of the American Medical Association asked five e-commerce companies — Amazon, Facebook, Instagram, LinkedIn, and Microsoft — to work harder to halt sales of illicit vaping materials, including the cartridges that some users refill with liquid they learned how to make on YouTube. Refillable vaping may be growing in popularity among young e-cigarette users. Some marketing data suggests that refillable vape cartridges have greatly increased in popularity since 2017, health policy expert Jidong Huang of Georgia State University told BuzzFeed News, driven by price: For example, a single-use Juul nicotine pod might cost $4 against a typical $20 bottle of refillable nicotine vaping liquid, which can have 20 to 30 uses. “It’s so much cheaper,” Huang said. It’s not clear how many home cooks have been inspired to brew their own THC vaping liquid by YouTube videos, many of which come with warnings that they should only be imitated in places where cannabis is legal. And the methods on display largely seem to be for making small batches of oils, so it is unlikely they could also be used for large-scale productions. Still, the home-cooking videos offer essentially no safety testing of the products they create, and present multiple ways that dangerous contaminants might get into the vaping liquids, experts say. First, the cannabis used by people following their recipe might be contaminated with pesticides. “Most [cannabis] flower that’s not on the regulated market is likely going to have some type of pesticide or fungicide in there,” said Myron Ronay, CEO of BelCosta Labs, which provides cannabis-testing services for regulated manufacturers in California. Pesticides can be present even at very low levels that would go undetected by home equipment, he said. The results can be dangerous. The fungicide myclobutanil, for example, can transform into hydrogen cyanide when heated. Another pesticide commonly found on unregulated cannabis is chlorpyrifos, which has been linked to brain damage in children and was recently banned in California. And because of the process required to extract THC into an oil, people who vape are exposed to much higher concentrations of pesticides than people who smoke, vaping safety researcher Jenny Wiley of RTI International told BuzzFeed News. Other potential dangers lurk in the ingredients added to the THC for the extractions. Several of the videos reviewed by BuzzFeed News recommend using propylene glycol as a cutting agent to make the oils smoother, for example. But if heated beyond 450 degrees, propylene glycol turns into formaldehyde. The cartridges — the overwhelming majority of which are cheaply sourced from China — might also contain heavy metals, like lead and cadmium, that can leach into people’s lungs once heated. The overarching challenge is that home cooks have almost no way of ensuring that what they’re using is safe and toxin-free, Ronay said. In contrast, legitimate suppliers in states where marijuana is legalized are required to test ingredients at every step of the way before a product is sold. “Even if these people can get clean flower, can get clean vape pens, how do they know all the individual components they’re sourcing with and making the THC liquid, how do they know all the components are good and clean?” Ronay said. “They have no idea. They’re just making assumptions.” But Ronay argued that the videos shouldn’t necessarily be taken down, either, since cannabis is legal in some places.

Tap to play or pause GIF Tap to play or pause GIF Peter Aldhous / BuzzFeed News / Via cdc.gov Vaping-related injuries have now been confirmed in every state but Alaska.