Oct. 2, 2019 -- More than a month after the first vaping-related death, the CDC has beefed up its recommendation to avoid e-cigarette or vaping products, and it warned users to avoid products that contain THC in particular. This came after reports that most people affected with the vaping-related lung illness had vaped THC, often bought on the black market.

Even so, the CDC emphasizes it has still not zeroed in on a single cause, although chemical exposure is suspected.

With cases now surpassing 800, and at least 17 deaths, what's taking so long to figure this out?

Tracing the cause of any outbreak is complicated, says Laura Crotty Alexander, MD, an associate professor of medicine at the University of California San Diego, who has studied vaping for several years. She and other experts interviewed say this outbreak has many complications, including:

  • The sheer number of ingredients and additives vaped
  • The variety of devices
  • The growth of vaping
  • The wide segment of the population that vapes
  • The poor or reluctant recall of patients to report what they vaped
  • The role of black market vaping cartridges

Alexander also brings up another possibility: ""These cases may not all be the same thing." She belongs to a group of vaping researchers who meet online often to discuss the latest findings on the health effects of vaping. Different chemicals involved in the outbreak may lead to different symptoms in patients, creating subsets of patients rather than a single cause leading to a single condition, she says. At this point, that's just a theory, she emphasizes.

Patients report a history of vaping before getting a cough, shortness of breath, chest pain, nausea, vomiting, diarrhea, fever, and belly pain. Some have needed to be put on ventilators.

The idea of a combination of factors makes sense, says Kyle Boyar, a cannabis scientist and vice chair of the American Chemical Society Cannabis Chemistry Subdivision. Labs are testing more substances as the investigation unfolds, he says. But "we have so many different vape mixtures that are out there. There are trends, especially in the black market. [They will say] 'I heard this guy is using this, it works really well.' '' So the ingredients change.

As the substances change, testing labs struggle to keep up. "Until you know that something is a risk, it's impossible to test for everything," Boyar says.

Emerging Clues

Despite the unknowns, more clues about the cause or causes are emerging as federal, state, and independent experts gather information. The FDA is analyzing samples submitted by states for a broad range of chemicals, including nicotine, THC and other cannabinoids, cutting agents, additives, pesticides, opioids, poisons, heavy metals, and toxins.

Among the results of investigations:   

THC's role: THC products appear to play a major role in the lung illness. The CDC analyzed information on 514 patients who self-reported their product use. Of these, 77% used products that contained THC, with or without nicotine. Nearly 20% of these patients used flavored e-liquids.

In another recent CDC report, researchers found a similar profile in Wisconsin and Illinois patients. Of 86 patients interviewed, 87% reported using e-cigarettes with THC during the 3-month period before getting sick.

More than half of the patients reported daily use of THC or nicotine-containing e-cigarettes.

The Black Market Factor: Most of the Illinois and Wisconsin patients said they used illicit products that contained THC sold as prefilled cartridges, the report found. They obtained them from ''informal sources."

No single brand or product was identified, but a high number -- about 58 -- reported using Dank Vapes. "Dank Vapes appears to be the most prominent in a class of largely counterfeit brands," the researchers write, "with common packaging that is easily available online that is used by distributors to market THC-containing cartridges with no obvious centralized production or distribution."

Numerous other brands of products that contain THC and nicotine were reported, including: 

  • TKO
  • Off White
  • Moon Rocks
  • Chronic Carts
  • Cookies
  • Smart Carts
  • Kingpen
  • Dabwoods
  • Rove
  • Mario Carts
  • California Confidential
  • Cereal Carts
  • Supreme G
  • Juul
  • Smok
  • Suorin Drop
  • Naked
  • Solace
  • Mr Salt-E
  • Salt Nic
  • Air Factory
  • Vuse Alto

Vitamin E: In early September, lab test results from the New York State Department of Health found high levels of vitamin E acetate in nearly all the cannabis-containing samples analyzed there. 

The vitamin is not considered harmful when it’s used as a nutritional supplement or put on the skin. But when inhaled, the oil-like properties could be linked with the symptoms associated with the vaping illness, experts say. 

Cyanide: In a recent report, NBC News said that 10 black market THC cartridges tested for pesticides were all positive and contained myclobutanil, a fungicide that can turn into hydrogen cyanide when burned. 

NBC commissioned CannaSafe, a leading testing facility, to test 18 THC cartridges in all. Three were bought from legal dispensaries in California and were found free of heavy metals, pesticides, and solvents such as vitamin E. Of the 15 samples bought from the black market, 13 also had vitamin E. 

Vaping Industry Response

In a statement, Tony Abboud, executive director of the Vapor Technology Association, said in part: "There is clear and compelling evidence that demonstrates that the illnesses are caused by unregulated, black market THC and CBD products -- not regulated nicotine vapor products."

He said that generalizing the cause of the outbreak to all vapor products is a problem and misleading. It  does not give people enough information to protect themselves, and it may lead adults to start smoking regular cigarettes again.

Observations From the Trenches

Milton Teske, MD, a public health officer for Kings County, CA, said all his patients bought their THC off the street. He suggested a link early on between illicit cartridges and the vaping illness.

The idea that this may not be a single disease also makes sense, Teske says. His cases had mostly similar symptoms, and he suspects his patients bought black market cartridges with a high amount of vitamin E acetate added. The additive makes the product appear to be better but ultimately clogs their lungs.

He says the cyanide finding in the recent NBC testing may help explain why some of his patients reported overwhelming weakness. "A lot of patients were saying, 'I felt so weak.' "

A combination of factors and substances may lead up to the lung damage, Alexander says. She points out the sheer number of chemicals involved, especially ''when you look at all the flavors."

"I still think it has to be the THC and at least one other chemical," she says. "What the lungs are 'seeing' is more than what is in the e-liquid." For instance, it might be the metal in the coils interacting that is actually the toxin, she says, stressing she is only speculating. 

In a study published last year, researchers sampled 56 e-cigarette devices to see if metals in the coil of the device are transferred to the aerosol. E-cigarettes generate an aerosol by heating the solution, or e-liquid, with a metallic coil. The researchers found that e-cigarettes can be a source of exposure to toxic metals and to metals that can be toxic if inhaled, concluding that contact with the coil could cause  e-liquid contamination. 

While some of the reported deaths have happened in people with other lung issues, in general, the condition ''doesn't come across as a disease that has been building up for years," Alexander says. 

On average, she says, patients are feeling sick about 6 days before they seek medical attention. "It comes across as an acute chemical pneumonitis [inflammation], with the lungs damaged in a short period of time."

In addition to finding out what is causing the lung injuries, experts have another challenge: figuring out the best treatment and monitoring plan for patients to restore as much of their lung function as possible.

Steroids are the recommended course of treatment, based on case reports from doctors treating some of the early cases. But like so much about this illness, even that is not definite, Alexander says. It's believed steroids work by tamping down the inflammation or injury in the lung with the illness. The reality? "We don't know if they help or not."


Show Sources

Kyle Boyar, vice chair, Cannabis Chemistry Subdivision, American Chemical Society.

Laura Crotty Alexander, MD, associate professor of medicine, University of California San Diego.

Milton Teske, MD, public health officer, King County, CA.; emergency room doctor, Adventist Health, Hanford.

Statement, Vapor Technology Association, Sept. 30, 2019.

Morbidity & Mortality Weekly Report,Sept. 27, 2019.

News release, CDC, Sept. 27, 2019.

CDC: “Outbreak of Lung Injury Associated with E-Cigarette Use, or Vaping,” Sept. 27, 2019.

NBC: “Tests show bootleg marijuana vapes tainted with hydrogen cyanide.”

FDA: “Lung Illnesses Associated with Use of Vaping Products,” Sept. 26, 2019.

News release, New York State Department of Health, Sept. 5, 2019.

Environmental Health Perspectives, Feb. 21, 2018.


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